Weigh In On This

It is a fact that many pet dogs (more than 50 percent by several accounts) are overweight. I reviewed the current statistics regarding canine waistlines in an earlier blog, “Do you think I look fat in this collar“. In that essay, we learned that owners of overweight dogs have a tendency to incorrectly assess their dog’s body condition, almost always underestimating weight and seeing a dog who is overweight as being ideal.  Kinda like the portly fellow and his mirror below.

Fat Man

LOOKIN’ GOOD DUDE, LOOKIN’ GOOD

One suggestion to reduce this epidemic of perceptual disconnect is to post canine body condition score (BCS) charts in veterinary clinics. The reasoning is that veterinarians will use these charts to educate their clients and help owners to get a better handle on Rover’s weight problems. Of course, such charts are only helpful if the veterinarian chooses to use them and then actually discusses Rover’s weight with the client.  Therefore, as a follow-up question to this research, one might ask, “Do veterinarians regularly access the body condition of dogs during routine visits?” Lucky for us, a group of researchers recently asked exactly that question.

The Study: Private veterinary practices in England, Wales, Scotland and Northern Ireland were recruited to participate.  Data from over 49,000 patient visit records were collected and were examined for the inclusion of a weight diagnosis (overweight or obese). When a diagnosis was found in the record, the dog was matched with a control dog using the criteria of age, sex, neuter status, breed and of course, weight. However, the control dog did not have a recorded diagnosis of being overweight. This research design is called a “case controlled study” and it allowed the researchers to examine various factors that influence whether or not a veterinarian will focus on a dog’s weight status during a routine veterinary visit.

Results: Of the 49,488 dogs whose records were examined, a notation for being overweight was found in only 671 cases (1.4 % of the dogs). Body condition score was recorded in less than 25 percent of patients. When comparisons were made between the dogs whose record showed a diagnosis of being overweight with their matched controls for which no diagnosis was made, only one health-related factor was found to influence whether or not a veterinarian discussed (and recorded) a dog’s overweight status. This was the diagnosis of osteoarthritis or lameness as a presenting problem. The researchers speculated that veterinarians would naturally include a thorough weight assessment in dogs with signs of arthritis, given the well documented association between overweight conditions and mobility problems in dogs. No other individual health problem or lifestyle factor was associated with a discussion of weight status during veterinary consultations.

Dr Says I am Fat

OR NOT

Take Away for Dog Folks

Since data from multiple sources tell us that upwards of 50 percent of pet dogs are overweight or obese, it appears that, much like dog owners, veterinarians are markedly under-diagnosing obesity in their canine patients. It also appears that including BCS charts in examining rooms is not the answer, since veterinarians recorded a body condition score for less than 25 % of their patients. It is important to note that an important limitation of this study was that it was able to examine only written patient records and had no way to review the actual conversations that had occurred between veterinarians and their clients. It is certainly possible that in at least some cases, Fluffy’s weight problem was discussed during the visit, but not recorded in her file. However, even if the methodology missed a lot of diagnoses,  1.4 % is still a heck of a long way from 50 %. It is reasonable to assume that a substantial number of the 49,000 dogs in this sample group were overweight but had not been diagnosed as such during their routine veterinary visits.

If veterinarians are not stepping up (as much as they should) and calling Rover rotund, who can? Well the good news is that in this day and age there are many other pet professionals who work with dogs on a daily basis, interact regularly and positively with a multitude of dog owners, and who are completely capable of assessing body condition and weight status in dogs. So, trainers, doggy day care owners, independent pet supply store owners, shelter/rescue professionals, dog walkers, and pet sitters – consider this your call to arms! Help out your clients by educating them regarding good feeding and exercise habits for their dogs, carry a BCS chart with you or post one in your business (better yet, have a scale handy), and gently but firmly encourage your owners to prevent overweight conditions in their dogs to keep them healthy and happy throughout life.

Mocking Corgi

NO MOCKING ALLOWED

Cited Study: Rolph NC, Noble PJM, German AJ. How often do primary care veterinarians record the overweight status of dogs? Journal of Nutritional Science, 2014; 3:e58;1-5.

Fear Itself

Last year, on the drive home from our annual vacation in Bar Harbor, Maine, our 11-year-old Brittany, Vinny suddenly and inexplicable awoke from a sound sleep and began to tremble, pant, pace, and obsessively lick at the sides of his travel crate. When I crawled back over the seat to find out what was wrong, Vinny’s eyes were “squinty” and he avoided looking at me as he continued to lick and pant. Mike immediately pulled over to a rest area and we got Vinny out of the car. As soon as he was on the ground and moving about, Vinny relaxed, looked at us calmly, gave each of us a nice Brittany hug, and off we went for a little walk. Perplexed, we thought that maybe he had to eliminate (nope, no urgency there), was feeling carsick (no signs), or had a bad dream (who knows?). Within less than a minute, our boy was his typical happy self, showing no signs at all of distress. We loaded all of the dogs back into the car and Vinny continued the journey home with no further incident. We still are not sure what triggered this odd stress episode in our boy. He has had one (equally perplexing) recurrence since, continues to be healthy and happy, and we continue to monitor him carefully both at home and when he is traveling with us.

Vinny Loves Bar Harbor

HAPPY VINNY IN BAR HARBOR, MAINE

Recognizing Stress and Fear

It is important for dog owners to recognize and respond to signs of stress and fear in our dogs. If we are sensitive to their emotional states and are accurate in our interpretations, we can respond appropriately to situations in which a dog is uncomfortable, stressed, or frightened. Because nonspecific signs of stress can be the first signs of illness or injury, attending to these promptly may help us to get our dogs the medical attention that they need before conditions worsen or escalate into an emergency. It is well-known that perceiving and understanding the emotions of others is a basic human social skill. We use these perceptions on a daily basis when we interact with other people – family members, friends, and even strangers. Interestingly, while most of us are capable on some level of reading the emotional states of other humans, studies have shown that these abilities vary tremendously among individuals. Similarly, because many share our lives with dogs, it follows that we use these same skills when interpreting the emotions of our canine friends.

fearfuldog15

CAN YOU RECOGNIZE FEAR IN DOGS?

Studying Perceptions

However, until recently, the accuracy of our perceptions of dogs’ emotional states had not been studied. Two research studies examined the cues that we use and our levels of accuracy when we perceive fear and stress in our canine companions.

Study 1: The first was conducted by researchers in the Department of Psychology at Columbia University in New York (1). The study team produced a series of video clips of dogs and embedded them in an on-line survey. Participants viewed the videos and then were asked to classify each dog’s emotional state using one of five possible descriptors (angry, fearful, happy, sad, or neutral). The first four of these are called “primary emotions” and were selected because research has supported the existence of these emotions in dogs and other animals. Although the study participants had 5 choices, the videos in the study only showed dogs demonstrating two possible emotions, either happiness or fear. All of the videos had been pre-categorized into the two emotion categories by a panel of dog behavior experts prior to the start of the study. After identifying each dog’s emotion, participants were asked to describe the specific features of the dog that they felt led them to their conclusion. For example, if a person classified a dog as showing happiness, she might say that the dog’s facial expression, ear set, and wagging tail were important features that conveyed this state to her. Last, the participants were asked to rate the level of difficulty that they experienced while attempting to interpret the emotions of each dog and to provide an estimate of overall confidence in their accuracy.

Results: Over 2000 people completed the survey and were divided into four dog experience categories based upon their dog ownership and professional histories. These were non-owners, owners, dog professionals with less than 10 years of experience, and professionals with more than 10 years of experience. It was somewhat surprising to find that the vast majority of people who completed the survey, more than 90 percent, correctly identified happy dogs in the video clips, regardless of the person’s level of dog experience. This means that most people, even those who have never owned a dog, could look at a happy dog and see…..a happy dog! This is good news.

Happy Face 3

PEOPLE KNOW A HAPPY DOG WHEN THEY SEE ONE!

However, when it came to recognizing fear in dogs, the news was not quite so positive. While more than 70 percent of dog professionals correctly identified the fearful dogs, this proportion dropped to 60 percent of dog owners, and to only 35 percent of non-owners. Put another way, this means that 40 percent of dog owners and 65 percent of non-owners were unable to correctly identify signs of fear and stress in an unfamiliar dog. Moreover, a substantial number of the non-owners (17 percent, or about one in six people) misclassified a fearful dog as a happy dog. This statistic is especially troubling, given the potential dangerous outcome of such mistakes. A person who approaches a dog who they believe to be friendly but who in effect is fearful, will at the very least increase the dog’s fear and distress and could potentially cause a defensive response in the dog, leading to a snap or bite. The features of the dogs that participants used to make their decisions also varied with experience level. A person’s tendency to focus on a dog’s facial features (eyes, mouth, ears) increased significantly along with experience. Inexperienced participants used primarily the dog’s tail and body posture to inform them about the dog’s emotional state. Conversely, more experienced people identified both facial expressions and body postures as important features when assessing a dog.

Interestingly, but perhaps not surprisingly, the results of this study are consistent with studies of human abilities to perceive and interpret the expression of emotions in other people. We are generally more sensitive to and more accurate at interpreting happy facial expressions in other people than we are when responding to fearful expressions. Moreover, while social experience seems to have little effect upon our responses to happy faces (we show a proficiency to do this at a very young age), having varied and extensive social experience is an important factor in determining our success at perceiving fear and stress in other people. In dogs, this study tells us that dog-related training and experience enhance our tendency to pay attention to dogs’ facial expressions along with their body postures and enhances our ability to correctly perceive fear.

Study 2: While the first study provided a general test of how people perceive fear in unfamiliar dogs, the second examined the ability of dog owners to recognize signs of stress in their own dogs (2). This study was conducted by researchers at the University of Pisa in Italy with a group of almost 1200 dog owners recruited through veterinary clinics. Participants first completed a questionnaire in which they were asked about stress in dogs and its potential health and behavioral consequences. They then identified what they believed to be signs of stress in dogs and estimated the level of stress in their own dog.

Results: More than half of the owners (60 %) were found to have a clear understanding of what stress is and how it can affect a dog’s emotional state and health. However, about 20 percent of owners (one in five) believed that experiencing stress had no negative physical or emotional consequences on dogs. (In other words, while they agreed that it occurred, they thought it was no big deal). The behaviors that owners most frequently identified as reflecting stress in their dog included trembling, whining/crying, excessive barking, and panting. In contrast, very few owners identified more subtle behaviors such as avoiding eye contact, turning away, yawning, nose licking, or yawning as signs of stress in dogs. Those owners who self-reported as being highly concerned with their dog’s stress level were more likely to identify these less obvious signs as important. Overall though, owners tended to miss many of the facial expressions (squinty eyes, avoiding eye contact, changes to ear set, retracted commissures) that most trainers immediately look for when they are assessing a dog’s stress level. Like the first study, this suggests that it is these more subtle facial cues of stress and fear that may be missed if a person is only paying attention to the more obvious body posture signs.

Take Away for Dog Folks

These two studies provide complementary information about the behavior cues that people pay attention to when attempting to decipher a dog’s emotional state. The first showed that even inexperienced people were able to correctly identify a dog who is happy and relaxed. However, perceptions of fear were strongly correlated to how much prior experience a person has had with dogs. As experience level increased, not only were people more likely to be correct, but they also were more likely to pay attention to a dog’s facial expressions than were people who did not spend much time with dogs. We also learned that dog owners are more likely to focus attention on their dog’s body posture, vocalizations and movements than on the more subtle signs of stress that involve a dog’s facial expressions and eyes.

Why it matters: Accurately recognizing fear and stress in dogs is an important skill set to have. Understanding our own dog’s emotional state allows us to respond by helping him out of situations that cause fear and reducing or eliminating triggers of stress when they are under our control. For trainers and behaviorists, working with owners who are sensitive to their dog’s stress response promotes the development of a more effective training and management plan. On a societal level we all benefit from a universal understanding of the behaviors, body postures and facial expressions that convey happiness versus fear or stress in dogs. Correctly interpreting a dog’s behavior is always enhanced by attending to both body posture and facial expressions. However, interpretation of dogs’ facial expressions may not come naturally to many people. This knowledge emphasizes the importance of teaching the subtleties of canine facial expressions in training classes, behavior education courses, and bite prevention programs. Moreover, the statistic suggesting that one in five owners do not consider the effects of stress in their dogs to be of negative consequence tells us that education is also needed regarding the health and welfare impacts of stress and fear on our dogs’ well-being and quality of life.

Here at home, Mike and I are still uncertain about what caused Vinny’s acute stress response during our vacation trip. As Vinny has aged he has become somewhat more sound sensitive, which is not unusual in senior dogs. However, even though we responded quickly at the time and he apparently recovered, we did not learn enough from the episode to determine a possible underlying cause. Perhaps we will never know. Regardless, I do know that paying attention to all of Vinny’s signs – body language, facial expressions, and eyes, will help me to understand him, care for him, and love him as best we can.

Vinny and Cooper Aunt Betty Pond Run

SENIOR BOY VINNY HIKING WITH HIS PAL COOPER IN BAR HARBOR

Cited References

  1. Wan M, Bolger N, Champagne FA. (2012) Human perception of fear in dogs varies according to experience with dogs. PLoS ONE 7(12): e51775. doi: 10.1371/journal.pone.0051775
  2. Mariti C, Gazzano A, Moore JL, Baragli P, Chelli L, Sighieri C. (2012) Perception of dogs’ stress by their owners. Journal of Veterinary Behavior 7:213-219.

NOTE: A version of this article was published in the December 2014 issue of Whole Dog Journal and is also included in my newest book, Beware the Straw Man: The Science Dog Explores Dog Training Fact & Fiction“.

 

What’s the Deal with Meals?

 

 

nestle-purina logo            Versus 2              Blue Buffalo Logo

The Pet Food Wars: In May 2014, Nestlé-Purina, the largest producer of pet foods sold in the U.S., filed a lawsuit against Blue Buffalo, a competitor. Among other things, the lawsuit alleged that Blue Buffalo’s marketing claims—that their foods contained no by-product meals—were false and disparaging to other companies’ products. According to the report of a testing laboratory hired by Nestlé-Purina, at least a few varieties of Blue Buffalo dry extruded foods (kibble) did indeed contain poultry by-product meal, comprising as much as 25 percent of the meal in some of its products. As is the way of the modern pet food industry, within days, Blue Buffalo responded with a countersuit of its own, accusing Nestlé-Purina of defamation, unfair competition and false advertising.

Central to this public (dog) food fight was the belief, strongly promoted by Blue Buffalo, that chicken or poultry meals are of superior nutritional value to by-product meals, and that high-quality dog foods contain the former and reject the latter. (It is of interest to note that Nestlé-Purina sidestepped the nutrient quality issue altogether in their lawsuit. Rather, they contended that Blue Buffalo had falsely promoted itself as being completely transparent to its customers.)

keep-calm-and-deny-deny-deny-4

Deny, Deny, Deny: Initially, Blue Buffalo responded to the allegations with denial. Both companies launched public-relations campaigns that included strongly worded letters to consumers. However, in October, Blue Buffalo had to eat crow (meal?) when they announced that one of their suppliers, Texas-based Wilbur-Ellis, had mislabeled an ingredient, which resulted in the presence of poultry by-product meal in some of their foods. In the words of Blue Buffalo’s founder, Bill Bishop: “So, while their customers were ordering and paying for 100 percent chicken meal, at times they were receiving shipments that contained poultry by-product meal. As a result, we have stopped doing business with this plant.

What is the truth? Are by-product meals lower in quality when compared with meals? Should discerning dog owners avoid chicken or poultry by-product meal and choose only foods that contain chicken or poultry meal? And is this a reliable way to distinguish between high-quality dog foods and foods of lesser quality?

Perhaps the best place to start is with an understanding of what a “meal” actually s.

Meals – The Protein Ingredient: Every ingredient that goes into a dog food contains a unique set of essential nutrients that it contributes to the finished food. In commercially prepared dry (extruded) dog foods, various types of meals are used to provide protein. These are classified in several ways.

  1. Plant vs. Animal Source: Examples of commonly used plant-based protein meals are corn gluten meal, soybean meal and pea protein (or meal). In general, plant-based protein sources are an inexpensive source of protein and are found in foods marketed to pet owners interested in economy. The quality of these meals is moderate to low in terms of amino acid balance and digestibility, although several protein sources are used to ensure that all essential amino acid needs are met. Animal-source protein meals, on the other hand, vary tremendously in both source—animal species—and in quality measures such as digestibility, amino acid content and amino acid availability.
  2. Species vs Generic Group: Animal source protein meals may be provided as species-specific meals or as generic animal groups. Examples of species-specific meals are chicken, bison, beef, salmon, venison, turkey and lamb meals. Alternatively, these meals may be classified more largely as poultry (contains varying amounts of chicken, turkey or duck), fish (contains multiple fish species), or meat (contains varying amounts of pork, beef or sheep). When you see a named species as the major protein meal ingredient, it generally indicates that the food is of higher quality (or at least a better-regulated product). Ingredient supply companies are required to keep these ingredient streams separate and designated, which means that sources are not mixed and translates to a more uniform product and greater regulatory oversight. Conversely, the generic term used to describe a group of food animals means that the meal may contain a mixture of species with no guarantee of any particular animal species or proportions in a given product. At the production level, this also means that several ingredient streams are combined, with varying sources of origin, regulatory oversight and quality attributes.
  3. Meals vs. By-Product Meals: The term “by-product” is the designator receiving the most attention. It is important to know that on pet food labels, this term is only applied to chicken and poultry meal. And, the distinction is largely bureaucratic; the Association of American Feed Control Officials (AAFCO) sets the definitions for ingredient terms and they have not designated a by-product meal term for any other animal protein meal. The closest they’ve come is “meat” meals versus “meat and bone” meals; the latter contains bone, which can reduce its quality as a protein source. (More about the purported differences between chicken/poultry meal and by-product meal later).

Meals are Produced via Rendering: Rendering is a cooking process that converts slaughterhouse products that have been deemed unfit for human consumption into a form that is regulated as acceptable for use in pet foods. Generally, animal parts used for rendering are those not typically consumed in our Western diet: organ meats such as spleen, kidneys, liver; stomach and intestines; varying amounts of bone; and, in the case of poultry, necks, feet and heads. In addition to slaughterhouse waste, “spent” layer hens from the egg industry and food animals found to be too diseased or injured to pass inspection for use as human foods may also end up at the rendering plant. Classified during the slaughter process as “inedible,” these parts are redirected into an alternate supply stream and are handled, transported and processed differently than those intended for human consumption.

The Process: During the rendering process, the combined components are ground, mixed and heated to a high temperature (220° to 270° F), which cooks and sterilizes the mixture, effectively killing the microbes that are present. Sterilization is absolutely necessary because refrigeration is not required for the handling or transport of inedible foods. The resulting slurry is centrifuged at high-speed to remove lipids (fat). The removed fat is further processed and eventually is sold separately as chicken, poultry, or animal fat. The mixture that remains is dried and ground to a uniform particle size that ultimately has the appearance and texture of dry corn meal. Animal protein meals are very low in moisture and contain between 55 and 65 percent protein, making them a rich source of protein when included in a pet food.

Chicken Meal

THE END RESULT – CHICKEN MEAL

Why use Protein Meals? From a commercial perspective, meals are well suited for use in dry foods because they can be stored and transported easily, and have the low moisture content necessary for extrusion processing. By comparison, high-moisture protein ingredients, such as “fresh” chicken (or other meat), contribute only small amounts of protein by weight to the end product because the water is cooked off during the extrusion process. These ingredients may be listed first on a food’s ingredient list simply because they contain more than 65 percent water, and ingredients must be listed in predominance by weight at the time of processing. In reality, it is the dried meals, usually found within the first three to five ingredients on the list, that provide the bulk of dietary protein in dry dog foods.

It Aint’ your Grandma’s Roast Chicken: According to AAFCO, the term “meal” refers to the “dry, rendered product from a combination of clean flesh and skin with or without accompanying bone, derived from the parts of whole carcasses of [chicken/poultry], exclusive of feathers, heads, feet and entrails.” (1)  Although this definition seems to suggest that meals are produced from the same parts of the chicken that make it to the supermarket for human consumption, this is simply not true. As mentioned previously, animal protein meals are produced from slaughterhouse waste and other food animals that are deemed “not for human consumption” (i.e., inedible).

In the case of chicken, these waste products are predominantly “chicken frames,” the remainder of the chicken’s body after the parts destined for human consumption have been removed. More than 70 percent of a broiler chicken ends up in the supermarket, leaving about 30 percent in the frame, which is made up of a bit of muscle meat plus a lot of connective tissue and bone.

Chicken Frames

CHICKEN FRAMES

None of the animal protein meals that are used in the production of dry dog foods are produced from edible (human grade) meats. This is because rendering plants are in the business of taking inedible animal parts and converting them into a form that can be fed to non-human animals. Chicken meal comes from chicken frames that are designated as not for human consumption, not from supermarket chicken.

        Chicken Meal          Unequal Sign       Fresh Chicken             

The Deal (with By-Product Meal): By-product meals are composed of exactly the same chicken components found in meals, but by-product meals may also contain varying quantities of heads, feet and viscera (guts). Therefore, the difference between a chicken (or poultry) meal and its respective by-product meal is the inclusion of heads and necks, feet, and guts (viscera) in the latter and the exclusion of those body parts from the former. On the face of it, this appears to be an obvious quality distinction. After all, any product that has heads, feet and guts in it not only sounds yucky, but certainly must also be of poor quality, right?

Well … it depends.

Given this definition, the general (and understandable) perception is that meals will be of higher quality than by-product meals. This is clearly the conclusion that Blue Buffalo and other pet food companies that make “No By-Products!” claims on their labels are banking on. However, consistent and substantial quality differences between the two ingredient types are not reported. The fact is that the inclusion of additional body parts (heads, feet and guts) in by-product meals can reduce, maintain or improve the quality of a meal (2).

Beaks, Feets and Guts, Oh My! These three additional parts, although certainly not very appetizing to most people, have varying nutritional value as food ingredients. First, the protein quality of viscera (internal organs and intestinal contents) is similar to that of chicken flesh components included in very high-quality chicken meals (and to what humans consume in a chicken dinner). In other words, including organ meats and intestinal contents in a by-product meal does not negatively affect the meal’s protein quality and may even improve it in a poor or average quality meal. Second, the inclusion of chicken heads in the mix results in a slight reduction in nutritional quality. This is because chicken brains are highly digestible while chicken skulls, being comprised of bone, are less so. So it appears to be a zero sum game when it comes to the added chicken heads. Last – chicken feet. As a food ingredient that is intended to provide dietary protein, feet are simply bad and have measured quality values similar to feeding connective tissue or bone residue.

Feet Less than symbol Heads  Less than symbol Chicken Guts

       FEET (BAD)                                        HEADS (LESS BAD)                           GUTS (BETTER)

Collectively speaking, including additional body parts in a by-product meal may affect the resultant product’s protein quality either positively or negatively when compared with its corresponding meal. The influence depends largely upon the actual proportion of the three different body parts that are included in the end product: if there are lots of guts, quality improves. Heads: could go either way. Feet: bad news.

And, by the way, specifics on the type and quantity of these additions is information that consumers are never privy to.

So, Why All the Hype? Studies of the digestibility and protein quality of meals and by-product meals have found that as a group, meals are slightly more digestible and contain slightly more available essential amino acids than their associated by-product meals (3,4). However, there is also a lot of overlap between the two ingredient groups, meaning that a given meal may be better, equal to or even lower in quality than a given by-product meal.

Overall, the differences that have been found are neither dramatic nor worthy of the hysteria that seems to accompany the word “by-product” among dog owners and some pet food companies. Therefore, the marketing hyperbole and excessive “patting oneself on the back” by companies that include meals but not by-product meals should be viewed by all dog owners with a hefty dose of skepticism. True, there is some difference, but probably not enough of a quality difference to warrant the inflammatory language and excessive claims that are being made by companies jumping on the by-product-free bandwagon.

soapbox

Draggin’ Out the Ol’ Box Again: I would suggest that this exaggeration of difference has occurred (and been actively promoted) because there are so few available ways for dog owners to accurately assess the quality of ingredients, especially protein ingredients, in commercial pet foods. As a result, this single AAFCO-defined difference (meals vs. by-product meals) has caught on like a house on fire, with marketing campaigns flinging additional gasoline to fuel the flames and causing this distinction-without-a-difference to garner more importance than it comes even close to warranting.

It is an unfortunate paradox that one of the most important nutrients for dogs (protein) is supplied by a type of ingredient (protein meals) that consumers have almost no way of evaluating. This is especially concerning given that animal-source meals can vary tremendously in the components that make them up and ultimately in their quality (i.e. in nutrient content and digestibility). The three designators discussed previously —plant- vs. animal-source, species vs. generic and meal vs. by-product meal — are the only protein-ingredient quality designators available to consumers. This might not be an issue if they were in truth the most important quality differences among animal protein meals. However, they are not. Animal protein meals differ in ways that are invisible to consumers and can significantly influence the quality of the foods in which they are used:

  • Bone and connective tissue: Animal-source protein meals contain varying amounts of bone and connective tissues (this pertains to both meals and by-product meals), which affects the product’s protein quality and mineral balance. Bone matrix and connective tissues contain the protein collagen, which is poorly digested and utilized when included as a dietary protein source, and bone contributes excess amounts of calcium and several other minerals. Meals that are high in collagen and minerals from bone and connective tissues are of lower quality than those that contain a larger proportion of muscle meat.
  • Transport and contamination: Because inedible food products are not refrigerated or subject to the same handling regulations as foods destined for human consumption, both the handling and transportation of raw materials can affect the quality of the end product. If rendering is conducted at the slaughterhouse of origin, the meal is usually produced within a day or two following slaughter. However, when raw materials are transported to a rendering plant in another location, the time spent during transport under unrefrigerated conditions can lead to increased microbial contamination and oxidative damage.
  • Processing: Differences among rendering plants also exist and are important for the end product. High temperatures or excessively long cooking can damage a meal’s protein, making certain essential amino acids less digestible and available.
  • Supplier integrity: Finally, as seen with the Blue Buffalo case, pet food companies are at least somewhat dependent upon the integrity and honesty of their ingredient suppliers. A division within the animal feed industry designates some meals as pet-food grade and others as feed grade, with the former containing a lower percentage of ash (minerals) (5). In addition, some pet food companies select only meals that meet a particular standard, while others impose additional refining methods on their protein meals to increase digestibility and improve protein quality.
  • Tests that we do not hear about: Various analytical tests are used to measure a meal’s digestibility and amino acid availability, and many pet food companies also routinely measure the digestibility of their foods using feeding trials. However, this information is not easily available to consumers, and pet food companies are under no obligation to accept or reject meals of different quality levels or to share such information with consumers.

To date, there is no way for pet owners to differentiate among dry (extruded) dog foods that use high-quality animal protein meals and those that use poor-quality meals, other than the cost of the food and the three designators discussed previously. You can contact the company and specifically ask for information about the food’s protein digestibility and quality, of course. However, you may be disappointed. While researching my book Dog Food Logic, I contacted the manufacturers of more than 30 different pet-food brands and requested protein and diet digestibility information for each of the products. I received no reply at all from the majority of companies and useful information for just two of the brands.

 Are There Any Other Options? In today’s innovative market place, there are indeed a few. Two other animal-source protein ingredients (in addition to fresh meats prepared at home) are those that are either freeze-dried or dehydrated. Freeze-dried ingredients are typically used in raw food diets, but can also be cooked prior to packaging. Dehydration usually uses heat treatment to kill microbial growth and so moderately cooks the meat. These sources are likely to be of higher quality and digestibility because they have not undergone the high heat processing that meals are subjected to.

Dehydrated chicken                           Freeze dried chicken                 DEHYDRATED CHICKEN                                        FREEZE-DRIED CHICKEN 

If they are human-grade meats, all the better, as this means that the ingredients and the end-products were handled and produced using the same regulatory oversight as required with human foods. However, with a few exceptions, neither freeze-dried nor dehydrated meat sources are routinely used as the primary protein source in dry, extruded foods. Nor have I found a source of dried protein meals produced using human grade (i.e., edible) meat sources and human food processing methods. To do so (and to promote them as such) would add a dimension of choice and distinction regarding the quality of dry dog food that does not exist today. Dry extruded dog food continues to be the most popular type of dog food sold in the U.S., and I believe such products would be welcomed by owners willing to pay a bit more for a better regulated and higher quality food.

Take Away for Dog Folks: While rendered animal meals can be of high quality and can provide an excellent protein source in dry dog foods, if the animal-source meal has been poorly sourced, handled, processed, or regulated, its protein can be damaged, making it a poor source of essential amino acids for dogs and reducing the digestibility and quality of the entire diet. Unfortunately, there is no way for consumers to tell from a food’s label if the meal used is of high, moderate or low quality. Because meals make up the bulk of protein in dry dog foods, information about their quality, and by extension, how nourishing they are, is the most important consideration that we should be concerned with when we look at an ingredient list.

The problem is, despite what companies beating the “No By-Products” drum would like us to believe, we have no way of knowing which animal protein meals are better than others.

Cited References

  1.  Association of American Feed Control Officials. 2010. Official Feed Definitions; pp. 326–322.
  2. Aldrich, Daristotle. 1988. Petfood and the economic impact. Proceedings of the California Animal Nutrition Conference, Fresno, CA; pp. 1140–1148.
  3. Cramer, Greenwood, Moritz. 2007. Protein quality of various raw and rendered by-products commonly incorporated into companion animal diets. Journal of Animal Science 85:3285–3293.
  4. Locatelli, Howhler. 2003. Poultry byproduct meal: Consider protein quality and variability. Feed Management 54:6–10.
  5. Dozier, Dale, Dove. 2003. Nutrient composition of feed-grade and pet-food-grade poultry by-product meal. Journal of Applied Poultry Research 12:526–530.

*A version of this article was published in the Spring, 2015 issue of The Bark.

Death Throes of the Guilty Look

I just talked to a potential client who is interested in bringing his 7-month-old Golden Doodle to train with us at AutumnGold. His dog, Penny, has the usual young dog issues – jumping up, a bit of nipping during play, still the occasional slip in house training, etc. Penny also raids the kitchen garbage bin, removing and shredding food wrappers, napkins, and any other paper goodies that she can find. The owner tells me that he is particularly upset about this last behavior because he is certain that Penny “knows she has done wrong“. He knows this because…….wait for it…….”Penny always looks guilty when he confronts her after the dreaded act”.

If I had a nickel………

Like many trainers, I repeatedly and often futilely it seems, explain to owners that what they are more likely witnessing in these circumstances is their dog communicating signs of appeasement, submission, or even fear.

Guilty Look Fear Beagle               Guilt or Fear Shelter Dog               GUILTY LOOK?                                                            OR FEAR?

And, also like many other trainers, I often feel as though I am beating my head against the proverbial wall.

But wait! Once again, science comes to our rescue! And this time, it is a darned good rescue indeed.

science to the rescue

The guilty look is a difficult issue to study because it requires that researchers identify and test all of the potential triggers that may elicit it, as well as the influence the owner’s behavior and his or her perceptions of their dog may have. Tricky stuff, but lucky for us, several teams of researchers have tackled this in recent years, using a series of cleverly designed experiments.

Is it scolding owners?  The first study, published in 2009, was designed to determine if dogs who show the “guilty look” (hereafter, the GL) are demonstrating contrition because they misbehaved or rather are reacting to their owner’s cues, having learned from previous experience that certain owner behaviors signal anger and predict impending punishment (1).  The study used a 2×2 factorial design, in which dogs were manipulated to either obey or disobey their owner’s command to not eat a desirable treat and owners, who were not present at the time, were informed either correctly or incorrectly of their dog’s behavior. The box below illustrates the four possible scenario combinations:

2 x 2 Factorial

FOUR TREATMENT GROUPS IN STUDY 1

The Study: Fourteen dogs were enrolled and all of the testing took place in the owner’s home. All of the owners had previously used “scolding” to punish their dogs in the past and an additional one in five also admitted that they used physical reprimands such as forced downs, spanking, or grabbing their dog’s scruff. In addition, all of the dogs were pre-tested to ensure that they had been trained to respond reliably to a “leave it” command and would refrain from eating a treat on the owner’s instruction. During each test scenario, the owner placed a treat on the ground, commanded the dog to “leave it”, and then left the room. While the owner was out of the room, the experimenter picked up the treat and either (1) gave the treat to the dog or (2) removed the treat. Upon returning to the room the owner was informed (correctly or incorrectly) about their dog’s behavior while they were away. Each dog was tested in all four possible combinations. (For a detailed explanation of these procedures and controls, see the complete paper). Test sessions were videotaped and dogs’ responses were analyzed for the presence/absence of behaviors that are associated with the GL in each of the four situations.

The Results: Two important results came from this study:

  1. Scolding by the owner was highly likely to cause a dog to exhibit a GL, regardless of whether or not the dog had eaten the treat in the owner’s absence.
  2. Dogs were not more likely to show a GL after having disobeyed their owner than when they had obeyed. In other words, having disobeyed their owner’s command was not the primary factor that predicted whether or not a dog showed a GL.

First nail in the coffin – The owner’s behavior can trigger the GL.

What about Dogs Who “Tell” On Themselves? But wait, Joe next door (who happens to know a lot about dogs) says – “How do you explain my dog Muffin who greets me at the door, groveling and showing a GL, before I even know that she has done something wrong?”

Not to worry – The scientists got this one too.

Back off man Scientist

The Study: Experimenters set up a series of scenarios involving 64 dog/owner pairs (2). The testing took place individually in a neutral room with just the dog, the owner and the researcher present. After acclimatizing to the room and meeting the experimenter, the dog was commanded by the owners to “leave” a piece of hot dog that was left sitting on a table. The owner then left the room. In this experimental design, the experimenters did not manipulate the dog’s response. Instead, they simply recorded whether the dog took the treat or not. Before calling the owner back into the room, the treat (if not eaten) was removed. The owners then returned to the room but were not informed about what their dog did (or did not) do in their absence. The owner then was asked to determine, by their dog’s behavior whether or not the dog had obeyed their command. In this way, the experimenters ingeniously tested for the “dog telling on himself” possibility.

Results: Just as the first study found, a dog’s behavior in the owner’s absence was not correlated with showing a GL upon the owner’s return. (Corroborating evidence from independent studies is always a good thing). The researchers also found that when they controlled for expectations, owners were unable to accurately determine whether or not their dog had disobeyed while they were out of the room, based only upon the dog’s greeting behavior. In other words, the claim that dogs tell on themselves and therefore must have an understanding that they had misbehaved was not supported.

Second nail in the coffin – Dogs don’t really tell on themselves (it’s an owner’s myth)

The most recent study, published in 2015, parsed out a final two factors that could be involved in the infamous GL – the presence of evidence as a trigger and guilt itself.

Guilty Look Rover

Guilt itself: If indeed, as many owners insist, a dog’s demonstration of the GL is based upon the dog having an understanding of the “wrongness” of an earlier action, then this would mean that the trigger for the GL would have to be directly linked to the dog’s actual commitment of the wrongful act, correct? Likewise, if the dog herself did not commit a misdeed, then she should not be feeling guilty and so should not demonstrate a GL to the owner.  It is also possible that the mere presence of evidence from a misdeed (for example, a dumped over garbage tin) could become a learned cue that predicts eventual punishment to the dog. In this case, a dog would be expected to show a GL in the presence of the evidence, regardless of whether or not he or she was personally responsible for it. This last study tested both of these factors (3). Using a similar procedure to those previously described, the researchers created scenarios in which dogs either did or did not eat a forbidden treat in their owner’s absence. They then either kept the evidence present or removed it prior to the owner’s return to the room. Owners were instructed to greet their dog in a friendly manner and to determine whether or not their dog had misbehaved based only upon their dog’s behavior.

Results: Owners were unable to accurately determine whether or not their dog had misbehaved based upon their dog’s greeting behavior and the dog’s actions did not increase or decrease the inclination to greet the owner showing a GL.  A dog’s inclination to demonstrate a GL was also not influenced one way or the other by the presence of evidence. The second finding suggests that the presence of evidence is not an important (learned) trigger for the GL in dogs. Rather the strongest factor that influences whether or not a dog exhibits a GL upon greeting appears to be the owner’s behavior.

Third and final nail – Neither engaging in a misdeed nor seeing evidence of a misdeed accurately predict whether or not a dog will show a GL.

The witch is dead

DING DONG, THE GUILTY LOOK IS DEAD!

Take Away for Dog Folks:  This series of studies tells us that at least some dogs who show signs of appeasement, submission or fear (aka the GL) upon greeting their owners will do so regardless of whether or not they misbehaved in their owner’s absence. We also know that an owner’s behavior and use of scolding and reprimands are the most significant predictor of this type of greeting behavior in dogs. These results should really be the final death throes of belief in the GL. Good Riddance to it, I say.

Now, all that needs to be done is that trainers, behaviorists and dog professionals everywhere work  to educate and encourage all dog owners to PLEASE, PLEASE STOP DOING THIS:

Fear Guilty Look Husky             Fear not guilt

Cited Studies:

  1. Horowitz A. Disambiguating the “guilty look”: Salient prompts to a familiar dog behavior. Behavioural Processes 2009; 81:447-452.
  2. Hecht J, Miklosi A, Gacsi M. Behavioral assessment and owner perceptions of behaviors associated with guilty in dogs. Applied Animal Behavior Science 2012; 139:134-142.
  3. Ostojic L, Tkalcic M, Clayton N. ARe owners’ reports of their dogs’ “guilty look” influenced by the dogs’ action and evidence of the misdeed? Behavioural Processes 2015; 111:97-100.

Our Best Friends’ Friends

Our  Golden, Cooper has a friend named Pete. Cooper and Pete groom each other, take naps together on a favorite bed, and play their own special version of “wolf and caribou” around the dining room table. When Coop goes on walks, he likes to have Pete come along with us.

And oh yeah, Pete is our cat.

Pete and Cooper

Many folks who live with dogs and cats are not surprised by this friendship and have great stories of their own to tell about a special bond between a dog and cat. However, the myth that dogs do not particularly like cats certainly continues to persist.

funny-pics-dog-wants-the-cat-to-get-into-the-washer

Likewise, it is generally accepted that not all cats are pleased about having to share their home with a dog.

Cat Text about Dog

The underlying foundation for the assumption that dogs and cats cannot be friends is perhaps the fact that they are vastly dissimilar species, with different evolutionary histories, social behaviors and communication patterns. Apparently, their interest in play varies as well.

Funny-dog-and-cat-cartoon

Regardless, anecdotal evidence abounds about the ability of individuals from the two species to form close and enduring friendships. And, I found recently, there is even a bit of science to back up these stories.

The Study:  A group of investigators from Tel Aviv University in Israel interviewed 170 pet owners who lived with both a dog and a cat (1). The study also included direct observations of the pets in 45 of the homes.

Results: Not only do dogs and cats get along well, they also appear to be able to learn quite a bit about communicating with each other:

  • The majority of the owners (> 60 %) reported that their dog and cat were amicable and friendly toward each other and less than 1 in 10 owners reported aggressive behaviors.  (The remaining pets were largely indifferent to each other).
  • Mutual play made up a substantial proportion of the interactions between dogs and cats, as did staying in the same room or resting and sleeping  together. Interestingly, the cats in the study offered significantly more play soliciting behaviors to their dog friends than vice versa.
  • Perhaps not surprisingly, the two factors that were found to be important determinants for influencing the dog/cat relationship were the order of adoption (friendships were more likely when cats were adopted first) and age of adoption (friendships were more likely when both animals were adopted when they were young).

Take Away for Dog (and Cat) Folks: One of the most interesting results from this study had to do with the types of communication signals that were used by the dog and cat friends. More than 75 % of the greeting behaviors between these friends occurred in the form of a  “nose-touch”, which is considered to be a common feline-specific greeting pattern, rather than a canine-specific greeting signal.

Chapter 1 Figure 9     Chapter 1 Figure 10

The researchers also reported several communication signals that had an unrelated or opposite meaning to the other species, yet were still correctly interpreted by the receiving animal.  Examples of these included lying on the back (submission or play in dogs versus aggression or predation in cats) and stretching out the forefeet (play in dogs versus aggression in cats). This is pretty cool stuff as it suggests that dogs and cats who share a home and become friends not only enjoy hanging out, playing, and resting together, but also appear to learn each others body language, even when certain signals may mean something very different in their own species.

As for Pete and Cooper, they both say, “Yeah? No big surprise there!”Pete and Cooper Playing1

Cited Study: Feuersten N, Terkel J. Interrelationships of dogs (Canis familiaris) and cats (Felis catus) living under the same roof.  Applied Animal Behaviour Science 2008; 113:150-165.

What’s in YOUR Food? (Revisited)

In an earlier blog essay, “What’s in Your Food?” I reviewed the results of four published studies that compared the animal protein ingredients listed on various pet food labels with the actual ingredients found in the foods. Multiple instances of mislabeling occurred in which undeclared animal species were included as ingredients and/or protein ingredients declared on the label were completely absent.

canned dog food comic

This month, another study was published (1).  Although this work was conducted in the UK and examined canned pet foods only, it was unique in one important way. Unlike the four previous studies, this group of researchers revealed the brand names of every single product that they examined.

All I can say is; It’s about time.

The Study: According to the authors, the objective of their study was to “examine the correlation between the composition of different animal proteins and the animal species disclosed on pet food labels“. Now, a naïve person might assume that such a correlation would be, oh, in the vicinity of, say…..1.0. But, we now know that this is not only naïve, but an assumption that has already been shown to be patently false. The authors tested 17 different brands of canned (i.e. wet) dog or cat foods available for purchase at UK supermarkets for the presence of cow, chicken, pig and horse meat DNA.

Results: None of the foods contained horsemeat. However, there the good news ends. Of the 17 foods, animal species that were not listed on the food’s label were found in 14 (82 %) of the products. Several errors worth noting include:

  • Hill’s Prescription Diet R/D Feline Weight Loss listed chicken immediately after pork on its ingredient panel, yet contained no chicken (0 percent).
  • Seven products included the phrase “with beef” in their brand name or prominently displayed on the label. The protein in four of these foods came predominantly from pork and chicken (75 to 86 % of protein). These products included a Pedigree (Mars) brand, two Nestle’-Purina brands, and a UK private label brand.
  • A Mars brand (Chappie) that stated “14 % whitefish” on its ingredient panel actually contained no fish at all; 100 % of its protein came from chicken. An ALDI private label brand called “Salmon in Pate” listed fish first on its label, did not report chicken at all, and yet was 92 % chicken.
  • Of six pet foods that highlighted “chicken” on the label or in the brand name, two products, both private label brands, contained more pig or beef protein than chicken protein.

soapbox

Up on my Soapbox: The authors of this study note that technically most (not all) of these foods were still in compliance with EU pet food regulations. The finding of large proportions of chicken and pork in foods that reported no such species on their ingredient panels was technically correct provided the term “meat and animal derivatives” was found somewhere on the list. Unbeknownst to most consumers, this term includes “all products and derivatives of the processing……of warm-blooded land animals“.  That covers everything from chickens to well, pretty much anything that has blood and feet. The second issue is the ubiquitous word “with“. Similar to regulations in the United States, EU standards require that pet foods using this descriptor contain….wait for it…..a minimum of only 4 % of the designated ingredient. (In the US, the minimum is a whopping 3 %). And as these products demonstrate, 4 percent is about what you get.

As the authors of this study note, and I agree, there appears to be a serious mismatch between label standards in the pet food industry and what consumers are lead to believe about the foods that they purchase for their animal companions. Is it not reasonable for my friend Alice to expect that the  food she selects for her Yorkie called “Gourmet Terrine with Chicken and Game” actually contain more than 1 percent of its protein from chicken, not as is the reality, almost 90 percent of it coming from beef? And when my elderly neighbor Joe carefully selects food for his beloved cat Pumpkin, is it silly for him to expect that “Felix Complete with Beef” contains a substantial proportion of, say……beef?

Just as we need increased transparency from the pet food (and human food) industry regarding the source of ingredients, processing methods, measures of quality, and safety records, it appears that we also need regulations that prevent rather than support misleading label claims and brand names. Is it really too much to ask that a pet food actually contains what it claims to contain (and nothing else)?

Cited Study: Maine IR, Atterbury R, Chang KC. Investigation into the animal species contents of popular wet pet foods. Acta Veterinaria Scandinavica 2015; 57:7-11.

 

 

 

Keep those Doggies Rollin’……Rawhide, Rawhide!

I have always hoped that someday I would find a connection between the Blues Brothers and dog nutrition. That day has come.

Rawhide, Rawhide: A dog person cannot walk into a pet supply store (or their own grocery store, for that matter) without noticing the explosion in the number of dog chews, dental devices and edible bones that are available for sale today. Some of these are biscuit or extruded concoctions containing a mixture of ingredients, while others originate from cow skin (rawhide chews) or are the left-over body parts of a hapless food animal (pig/lamb ears, hooves, and bully sticks).

If you do not know what a bully stick is, ask your mother. Better yet, ask your father.

rawhide knots    Bully Sticks   Pig ears  Hooves

Even as the selection of these items has expanded, nutritional information about them is still glaringly absent. Since all of these products are intended to be chewed slowly so that pieces or the entire product will be gradually consumed by the dog, we should at least be informed as to whether these items are actually digested by dogs, should we not?

Are they digestible? Dry matter digestibility refers to the proportion of a food that a dog’s gastrointestinal tract is capable of breaking down (digesting) and absorbing into the body. When we talk about the digestibility of a dog food, we are primarily concerned with its nutrient value and ability to nourish the dog. However, when we are considering the digestibility of rawhide treats, chews and dental products, the concerns are different but equally important. Any portion of a chew that is broken off and swallowed will travel through the length of a dog’s gastrointestinal tract, just like any other food. And, if the dog is able to bite off large chunks or swallow an entire chew at once, that piece has the potential to cause digestive upset, impede normal gut motility, or in the worse case scenario, cause obstruction if it is not dissolved and digested as it moves along.

Recently, a team of researchers at the University of Illinois decided to examine exactly this question by comparing the digestibility of different types of dog chews.

The studies: Two studies were conducted, both using an in vitro (test tube) technique that has been validated as a measure of the digestive conditions that occur in a dog’s stomach (gastric digestion) and small intestine (intestinal digestion). The first study compared in vitro dry matter digestibilities of sample products from six broad categories of dog treats (1). All of the products that were tested were produced by Hartz Mountain Corporation and the study was funded by the company. The second study compared just two types of treats, pork skin versus beef rawhide chews (2). The researchers also measured digestibility of the pork skin chew using a feeding trial with dogs. (For an explanation of digestibility trials with dogs, see Scoopin’ for Science). The reason for not doing a feeding study with the beef rawhide chew was not explained in the paper.

Results: Together, the two studies reported several interesting differences between the digestibility of dog chews:

  1. Chews made from pig’s ears, which are composed primarily of cartilage and the protein collagen had very low gastric (stomach) digestibilities (14 %). Although these were almost completely digested in the intestinal environment (90 %), the lack of change in gastric acid means that a pig’s ear treat, if swallowed, would potentially leave the stomach intact and enter the small intestine will little change in size and consistency.
  2. Similarly, with the exception of one product, rawhide chews made from cow skin were very poorly digested in the stomach. Intestinal digestion was almost complete for one product, but others continued to have low digestibility, even in the intestinal environment. The researchers noted that feeding rawhide chews to a dog who tended to consume large pieces could increase a dog’s risk for intestinal blockage.
  3. When a pork skin chew was compared directly to a beef rawhide chew, the pork skin product’s digestibility was significantly greater than that of beef rawhide chew. After six hours, which is approximately the time it takes for a meal to begin to leave a dog’s stomach and enter the small intestine, the pork chew was more than 50 percent digested, while the rawhide was only 7.6 percent digested. This low rate of gastric break down continued even when tested up to 24 hours. After simulation of digestion in the small intestine (the major site of digestive processes in dogs), the pork skin rawhide was almost 100 % digested, while the beef rawhide reached only 50 to 70 % digestion under the same conditions. Rawhide was digested up to 85 % only when exposed to the intestinal conditions for 24 hours.
  4. When dogs were fed one pork skin chew per day along with their normal diet, the overall digestibility of the diet increased. This corroborates the in vitro results and supports the conclusion that the pork skin chews were highly digestible.

Take Away for Dog Folks:

One of the most interesting results of these studies was the finding of such a large difference between the digestibility of pork skin versus beef rawhide chews. Because some dogs consume these types of chews rapidly and swallow large chunks, the fact that pork chews but not beef rawhides are highly degraded in the stomach and are highly digestible overall, is of significance to dog owners. These data suggest that if an owner is going to feed some type of rawhide chew (and mind you, I am not advocating for feeding these types of treats), but if one was choosing and had a dog who might consume the treat rapidly, feeding a pork skin chew appears to be a safer bet than a beef rawhide chew.

Second, it is important to note that all types of rawhide-type chews are composed of collagen, a  structural protein that makes up most of the connective tissues in the body. This is true for ears, pig skin, rawhide, and yes, even bully sticks. As these data show, collagen can be highly digestible (or not). The difference most likely depends on the source of the product and the type of processing that is used, both of which vary a great deal among products.

Feeding  dog a chew that is composed of collagen, even when it is highly digestible collagen, does not a nutritious treat make. Although collagen is a very important and essential protein in the body, it is not a highly nutritious food protein because it is composed almost completely of non-essential amino acids and is deficient in four of the essential amino acids. What this means from a practical perspective is that even though certain types of rawhide chews are found to be highly digestible and safe (from a digestibility perspective), this does not mean that they are providing high quality nutrition to the dog. In fact, they do not. While this research is important for pushing the peanut forward regarding the safety of these products in terms of digestibility, effects on gut motility, and risk of blockage, we still need more information (and selection) of chews for dogs that are both digestible and nutritious.

Cited Studies:

  1. de Godoy MRC, Vermillion R, Bauer LL, Yamka R, Frantz N, Jia T, Fahey GC Jr, Swanson KS. In vitro disappearance characteristics of selected categories of commercially available dog treats. Journal of Nutritional Science 2014; 3:e47;1-4.
  2. Hooda S, Ferreira LG, Latour MA, Bauer LL, Gahey GC Jr, Swanson KS. In vitro digestibility of expanded pork skin and rawhide chews, and digestion and metabolic characteristics of expanded pork skin chews in healthy adult dogs. Journal of Animal Science 2012; 90:4355-4361.

(Note: These studies and this blog essay do not address the ongoing and well-publicized problems with chicken jerky treats and illness in dogs. That is a topic for another time, another post).