Does the avoidance distance test at the feed barrier have scientific validity for evaluating reactivity to humans in Limousin breeding bulls?

Management of dairy heifers: Can operant conditioning be an effective and feasible tool to decrease stress and ease animals' close contact and handling?

Besides health monitoring, a regular check of dairy heifers' growth rate is desirable, but it is rarely done because procedures that require restraint and handling can be associated with substantial stress for both animals and farmers. Inexperienced heifers, especially if they are highly responsive to humans, may find restraint and handling potentially aversive. This study investigated whether training heifers of different age and responsiveness toward humans (RTH), through operant conditioning, could reduce stress in animals, ease close contact and handling, and be feasible in terms of farmers' effort. We assessed 60 Holstein heifers of 2 age classes (young, n = 29, 291 ± 39 d; old, n = 31, 346 ± 62 d) according to the avoidance distance test and classified them as confident (n = 20), neutral (n = 21), or nonconfident (n = 19). Half of the heifers of each age and RTH class were trained (n = 29), whereas the other half was not (n = 31). The trained heifers were subjected to target training for 8 sessions and positively reinforced with feed to allow being touched on the muzzle, rump, and perineum. If a heifer refused positive reinforcement, the trainer stepped back as negative reinforcement. In the last week of the experiment, the effect of training on the reaction to handling was assessed in all heifers. We measured heart rate, root mean square of successive interbeat interval differences (RMSSD), and fecal cortisol metabolites (FCMet). The presence of behavioral distress signs was recorded as well. The avoidance distance test was performed a second time 24 h after the measuring session. All of the trained heifers, regardless of RTH class, successfully accomplished the target training task in 6 sessions, each spending on average 25.3 s per session. All of the trained heifers allowed touches on the rump and perineum at the end of the fourth session. Training nonconfident heifers required more time compared with the others. Trained heifers showed higher RMSSD than nontrained heifers (14.2 vs. 16.9 ms, respectively), indicating a lower vagal tone, and thus, a slightly lower stress level than nontrained heifers. Training did not lead to differences in HR, FCMet, or presence of stress behavioral signs. Nonconfident heifers had the highest mean baseline FCMet values compared with neutral and confident heifers (38.4 vs. 30.3 vs. 29.1 ng/g, respectively). Nonconfident heifers also showed the lowest value of FCMet 12 h after the measuring session (36.7 vs. 44.6 vs. 49.7 ng/g), likely due to a decreased responsiveness of the adrenal gland to a stressor. The average avoidance distance decreased between the beginning and the end of the experiment, especially for neutral and nonconfident heifers, regardless of whether they were trained or not. These results show how using operant conditioning on some heifers not only decreased their vagal tone, but also reduced the responsiveness to humans of all the animals, trained and not trained; in the latter case, this reduction was through nonassociative learning, such as habituation.

Avoidance-related behavioral and blood-based physiological responses of Nguni and Boran cattle subjected to routine handling activities post relocation

Introduction

This study aimed to investigate the avoidance-related behavioral and blood-based physiological responses of Nguni and Boran cattle during routine handling activities post-relocation, with a particular focus on the effect of breed, week, and waiting time.

Methods

A total of 20 animals, 10 from each breed, were subjected to handling activities at fortnight intervals post-relocation. The animals were observed for entry time (ES), chute score (CS), kicking score (KS), blood sampling time, cortisol, and glucose concentrations. The data were analyzed using ANOVA and regression analysis.

Results and Discussion

Results showed that breed had a significant effect on avoidance-related behavioral responses (ES: p = 0.0032; CS: p = 0.0071; and EX: p = 0.0320), with Nguni cattle displaying more active avoidance behaviors compared to Boran cattle. Additionally, breed differences were observed in physiological responses, with Nguni cattle exhibiting higher cortisol and glucose levels compared to Boran cattle. Waiting time in the race had a greater impact on chute score (CS: p = 0.0037) and cortisol release (p = 0.0375) in the two breeds. Regression analysis revealed that the amount of time spent in the handling facility prior to sampling and the duration of blood collection significantly increased from week 3 to 15. Steers that waited in the race for more than 10 min had higher cortisol levels (p = 0.0031). These findings suggest that breed-specific management practices may be necessary to reduce stress-related responses and improve animal welfare during routine handling activities post-relocation. Overall, this study highlights the importance of considering the effects of breed, week, and waiting time when evaluating the avoidance-related behavioral and blood-based physiological responses of cattle during routine handling activities. These factors play a significant role in understanding and addressing the stress and welfare concerns associated with handling procedures, particularly after relocation.

Evaluation of Chute Exit, Novelty and Human Approach Tests in Mertolenga Beef Cattle

Livestock behavior and welfare are increasingly recognized to be related, not only to the animals' handling, but also with productivity. The present work was carried out at the Mertolenga Breed Testing Center and its objective was to evaluate the behavior of Mertolenga breed young bulls when exiting the chute, the reaction to novelty and human approach tests, as well as to understand if the responses between these tests are related. Twenty-nine Mertolenga-bred young bulls from 16 different farms, aged between 8 and 13 months, entered the study farm from the end of May to the beginning of June 2021. Data was collected on six different days and analyzed with the SAS^® 9.4 software. Older animals showed a tendency to leave the chute more calmly, take longer to touch the novelty ball and to touch the ball less often, with a consequent reduction in the likelihood of playing with it. In the human approach test, animals that came out of the chute more calmly allowed the human to come closer. These behavior tests should be further studied on potential sires, so as to increase docility and manageability of autochthonous beef breeds.

Behavioural Traits in Bos taurus Cattle, Their Heritability, Potential Genetic Markers, and Associations with Production Traits

Simple Summary

Cattle have the potential to seriously injure humans and cause damage to property. The risk of cattle reacting in a dangerous manner can be reduced through genetic selection for cattle which have a better temperament. A literature search was undertaken which returned papers which met the criteria of “Bovine”, “Genetics” and “Behaviour” or terms therein. Behavioural traits were grouped and their heritability, genomic associations and correlations with production traits examined. It was found that heritability estimates were more accurate in studies with large populations (n > 1000). Gene associations with behavioural traits were found on all chromosomes except for chromosome 13, with associated SNPs reported on all chromosomes except 5, 13, 17, 18 and 23. Generally, it was found that correlations between behaviour and production traits were low or negligible, suggesting that genetic improvement can be undertaken without negatively affecting production. There was variation between the results of the studies examined, and this underlines that any genetic study is population specific. Thus, to assess the heritability, genetic associations with production and genomic areas of interest for behavioural traits, a large-scale study of the population of interest would be required.

Abstract

People who work with cattle are at severe risk of serious injury due to the size and strength of the cattle. This risk can be minimised by breeding less dangerous cattle, which have a more favourable reaction to humans. This study provides a systematic review of literature pertaining to cattle genetics relating to behaviour. The review protocol was developed using the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) framework, with Population, Exposure and Outcome components identified as Bovine, Genetics and Behaviour respectively. Forty-nine studies were identified in the sifting and assigned non-exclusively to groups of heritability (22), genomic associations (13) and production traits related to behaviour (24). Behavioural traits were clustered into the following groups: “temperament, disposition and/ or docility”, “aggression”, “chute score”, “flight speed”, “milking temperament”, “non-restrained methods” and “restrained methods”. Fourteen papers reported high accuracy (Standard Error ≤ 0.05) estimates of heritability, the majority (n = 12) of these studies measured over 1000 animals. The heritability estimates were found to vary between studies. Gene associations with behavioural traits were found on all chromosomes except for chromosome 13, with associated SNPs reported on all chromosomes except 5, 13, 17, 18 and 23. Generally, it was found that correlations between behaviour and production traits were low or negligible. These studies suggest that additive improvement of behavioural traits in cattle is possible and would not negatively impact performance. However, the variation between studies demonstrates that the genetic relationships are population specific. Thus, to assess the heritability, genetic associations with production and genomic areas of interest for behavioural traits, a large-scale study of the population of interest would be required.

Association between breeding bulls' reactivity to humans or handling and their daily behaviour and growth

In beef cattle, reactivity to humans or handling by humans is considered a safety issue for farmers and to impact on productivity. Several testing procedures, associated with potential risks for both humans and animals, have been developed, involving simple human approach, free animals individually handled, or restraint in handling facilities. We investigated how such tests may be related to each other and which dimensions they reveal. Of particular interest is the tolerance towards human approach or handling involving human or chute restraint, and whether they could be linked to the daily activity of animals and their growth, potentially enabling this activity to be used as a proxy for evaluating this reactivity to humans and handing. We observed 498 Limousin breeding bulls, of up to 14 months of age, at a bull testing station during standardised behavioural tests involving humans and handling: human approach at the feed barrier or out of the home pen during individual morphological evaluation, docility test where the experimenter attempts to maintain the bull in the corner of a test pen, and during restraint in a chute for weighing. Routinely collected on farm at approximately 8 months of age, bulls' reaction scores to human approach were also available. The animals wore MEDRIA collars with 3D-accelerometers that continually monitored their daily activities (ingestion, rumination, rest, etc.). Three 2-week periods spanning 4 months were analysed. We conducted a varimax-rotated principal component analysis (PCA) on behavioural tests: the first component (23.63% of the variability) summarised scores during restraint in the chute, and the second component (19.36% of the variability) summarised avoidance distance score at the feed barrier, score during morphological evaluation, and docility score. The daily activity of the bulls was consistent across the three 2-week periods that were analysed and was not related to the PCA dimensions (P > 0.1). Animals that could be approached at a closer distance reached a heavier weight at the age of 400 days (P < 0.001). In conclusion, within the limits of the test used, breeding bulls' reactivity to humans or handling comprised at least two dimensions: reactivity to human approach and reactivity to restraint (in the chute); which cannot be predicted from the animal's daily activity. A bull's acceptance of being approached by humans was positively related to its growth.

Quality of Death in Fighting Bulls during Bullfights: Neurobiology and Physiological Responses

During bullfights, bulls undergo physiometabolic responses such as glycolysis, anaerobic reactions, cellular oedema, splenic contraction, and hypovolemic shock. The objective of this review article is to present the current knowledge on the factors that cause stress in fighting bulls during bullfights, including their dying process, by discussing the neurobiology and their physiological responses. The literature shows that biochemical imbalances occur during bullfights, including hypercalcaemia, hypermagnesaemia, hyperphosphataemia, hyperlactataemia, and hyperglycaemia, associated with increased endogenous cortisol and catecholamine levels. Creatine kinase, citrate synthase, and lactate dehydrogenase levels also increase, coupled with decreases in pH, blood bicarbonate levels, excess base, partial oxygen pressure, and oxygen saturation. The intense exercise also causes a marked decrease of glycogen in type I and II muscle fibres that can produce myoglobinuria and muscular necrosis. Other observations suggest the presence of osteochondrosis. The existing information allows us to conclude that during bullfights, bulls face energy and metabolic demands due to the high intensity and duration of the exercise performed, together with muscular injuries, physiological changes, and high enzyme concentrations. In addition, the final stage of the bullfight causes a slow dying process for an animal that is sentient and conscious of its surroundings.