“Methods used by Canadian dairy farmers for on-farm euthanasia and the emotions associated with the decision and the practice of euthanasia.” Journal of Dairy Science Vol. 106, No. 2, 2023. The objectives of this study were to describe current practices related to on-farm euthanasia performed by Canadian dairy farmers and to assess the emotions and complex feelings surrounding the act. For this purpose, a cross-sectional study design (a study in which data is collected from many different individuals at a single point in time) was used to gather this information through an online questionnaire completed exclusively by Canadian dairy farmers. A total of 479 dairy farmers from five provinces answered the survey.
The authors explain that euthanasia is the act of ending the life of an animal to relieve its pain and suffering, and that timely culling decisions are of the utmost importance. They indicate a study of culled cows arriving at slaughterhouses in Alberta, where almost 50% were considered unfit for transport upon arrival. This emphasizes the need for better end-of-life decisions for culled dairy cows. The authors explain that guidelines for the care of farm animals, including the use of acceptable euthanasia methods, are included in the Canadian Code of Practice for the Care and Handling of Dairy Cattle and the Dairy Farmers of Canada’s dairy quality assurance program, the proAction Initiative. These recommended practices outline that the chosen euthanasia method should cause the animal the least possible pain and stress, and that death must be confirmed. According to these documents, the acceptable methods for on-farm euthanasia of cattle are gunshot (free bullet); a penetrating captive bolt (PCB) followed by pithing, exsanguination or cardiac puncture; or fatal injection with barbiturates, which must be performed by a licensed veterinarian. A nonpenetrating captive bolt (NPCB) followed by exsanguination was also considered an acceptable method but only for bovines under 181 kilograms.
The authors provide some context for another aspect of this study indicating that the stress related to animal caretakers’ work, coupled with the lack of control over several elements of their daily lives, has been shown to lead to psychological distress, and that the impact of euthanasia on animal caretakers has also been observed for multiple animal species and in multiple professions. They say limited information exists on how performing on-farm euthanasia or making the decision to end the life of one of their animals affects farmers and cite a recent study where euthanasia of dairy cattle cared for by dairy workers in the U.S. has emerged as one of the factors responsible for the deterioration of the workers’ mental health.
The article concluded that the most used primary method of on-farm euthanasia was a firearm (more than 70%). Unacceptable euthanasia methods, such as standard 0.22-caliber long rifle for adult cows or no adjunct method following the use of captive bolt, were used by 25%, 18% and 58% of the participants for calves, replacement animals and dairy cows, respectively. Ninety-four percent of the participants reported the farmowner was the person who always or often made the euthanasia decisions. In addition, 32% of the participants reported the veterinarian always examined the animal before performing euthanasia, 51% reported at least one person received training to perform euthanasia, and 16% reported having a decision tree for euthanasia. It also concluded that 17% of the participants were troubled with the responsibility for ending the life of their animals, and 19% perceived other people on the farm to be uncomfortable with performing euthanasia. Half of the participants reported that people performing euthanasia on the farm felt at least one related painful emotion or complex feeling, and half reported they had at least one reason to feel anxiety or unease concerning euthanasia. The authors say they found there is a gap in training for farmers performing on-farm euthanasia and that the use of a decision tree to guide euthanasia decisions and the involvement of a veterinarian before performing euthanasia were limited.
“Invited review: Effect of subacute ruminal acidosis on gut health of dairy cows.” Journal of Dairy Science Vol. 105, No. 9, 2022. This article is a review about the effects of subacute ruminal acidosis (SARA) on the gut health of dairy cows. The authors say that SARA is assumed to be a common disease in high-yielding dairy cows that affects production, health and welfare and, although this disease has been studied and reviewed extensively, there is no full agreement on the etiology and symptoms of SARA. The term itself suggests that the disorder involves a depression of ruminal pH, but the authors say it has become evident that the symptoms of SARA are not solely caused by depressed ruminal pH.
The authors explain that studies on the prevalence of SARA on commercial dairy farms are limited and have mainly been conducted using rumenocentesis (rumenocentesis is the collection of rumen fluid by percutaneous needle aspiration, under local anaesthetic) approximately five to eight hours after feeding and using a ruminal pH threshold of 5.5. A comparison of these studies shows that they all included a limited number of cows and dairy farms, and that the diagnosis of SARA was solely based on ruminal pH collected on a single day. Also, the threshold pH of 5.5 was decided based on distinguishing groups of cows receiving either a low- or a high-forage diet, and not on differences in pH-related and non-pH-related symptoms between these groups. This may explain why studies on the prevalence of SARA reported that cows diagnosed with SARA did not have a lower frequency of ruminal contractions, fecal consistency and milkfat content compared with nonaffected cows. According to the authors, this suggests that either the threshold pH of 5.5 for the diagnosis of SARA by rumenocentesis is inaccurate, or that the models used for the experimental induction of SARA are not fully representative of “naturally occurring SARA.” They suggest that diagnosis of SARA on dairy farms should not be done based on the pH of ruminal fluid obtained by rumenocentesis alone. A combination of tests, including ruminal motility, markers of inflammation, fecal consistency and milkfat concentration, are probably more accurate and practical. High-yielding dairy cows commonly experience SARA and, as a result, poor gut health. The etiology of “poor gut health” is complex and multifactorial, and factors other than SARA also affect gut health. There is currently no well-defined term or accurate diagnostic tool for this “complex.” Gut health encompasses conditions and health of digesta, microbiota and mucosa throughout the gastrointestinal tract (GIT), not just in the reticulo-rumen.
The authors say the studies done around SARA have shown that the symptoms of SARA induced by excessive grain or starch feeding are considerably more severe than those of SARA resulting from diets containing insufficient coarse and physically effective fibre, possibly due to the lower starch content of digesta in the forestomachs and the large intestine in the latter challenges. Hence, the cause of ruminal pH depression during SARA may affect the symptoms of ruminal pH depression itself. On dairy farms, this ruminal pH depression can have many causes, which impedes conducting SARA challenges that are representative of on-farm conditions. The symptoms of excessive grain or starch feeding and grain-based SARA challenges are likely not caused solely by the resulting reduction in ruminal pH. In addition to reducing ruminal pH, these challenges affect the concentrations of many compounds in ruminal digesta. Several of the compounds identified are potentially toxic to the cow and can, therefore, cause health problems, especially when the barrier function of the GIT is compromised. The authors say future research is needed to understand which microbial metabolites challenge the maintenance of gut health in dairy cattle, as well as to determine their effective doses. SARA can be expected to affect the ruminal microbiota and cause ruminal dysbiosis (mainly by reducing the diversity and richness of the microbial population), which may lead to the establishment of opportunistic and pathogenic microorganisms in the GIT. An inflammatory response may also occur, but the authors say the full effect of the inflammatory response to SARA challenge in the production and health of cows is not yet clear.
