The Correlation between Play Behavior, Serum Cortisol and Neutrophil-to-Lymphocyte Ratio in Welfare Assessment of Dairy Calves within the First Month of Life

Welfare assessment of dairy calves is commonly conducted through the observation of their behavior and the analysis of physiological parameters. Despite the large number of studies on this topic, there is a lack of research on the possible correlation between the physiological parameters and behavior at basal level in dairy calves. For this reason, the present study aimed to investigate the possible correlations between serum cortisol, neutrophil-to-lymphocyte ratio (N/L) and locomotor play behavior in 21 Friesian dairy calves within their first month of life. Every week, an arena test after blood collection was performed. A significant positive correlation between serum cortisol levels and N/L (rrm = 0.381; 95% CI = 0.083, 0.617; p = 0.012) and a negative correlation between time spent running and N/L (rrm = −0.351; 95% CI = −0.575, −0.077; p = 0.012) were found. On the contrary, no significant correlation between time spent running and cortisol levels was detected. Cortisol levels and N/L were higher in the newborn and had a constant decrease until reaching a stable value after the 24th day of life. These findings suggest a better predictivity of N/L, compared to serum cortisol, on locomotor play behavior.

The Effect of Mother Goat Presence during Rearing on Kids’ Response to Isolation and to an Arena Test

The aim of the study was to examine how early permanent separation, separation during the day only, or full-time access to the mother goat affected goat kids during social isolation with a sudden sound of a dog bark at two weeks and two months, and a novel arena test with a novel object at two months. Kids permanently separated reduced their vocalization earlier and had a higher heart rate before and after dog bark during isolation at two weeks, no effect was found on the daytime separated kids. Daytime separated kids bleated more at two weeks and decreased heart rate after dog barking at two months. Daytime separated kids showed the strongest fear reaction in the arena test, no effect was found on the permanently separated kids. Kids separated early vocalized more before novel object and showed more explorative behavior afterwards. Our study shows different responses in goat kids separated early permanent, daytime separated, or kept full-time with mother, which demonstrates the importance of if and how the mother is present, and the impact of using a wide variety of physiological and behavioral measures when evaluating stress in animal welfare research.

Maternal reactivity of ewes at lambing is genetically linked to their behavioral reactivity in an arena test

In sheep, the bond between the dam and her lambs is established during the first hours of a lamb s life. Genetic variability for behavioral reactivity of ewes assessed in an arena test performed 24 h after lambing has already been reported. However, there is no evidence that this reactivity represents the ewe s maternal reactivity at lambing in outdoor conditions. The objective of this study was to investigate whether or not the behavioral reactivity of ewes in the arena test is genetically related to their maternal reactivity measured at lambing. A total of 935 Romane ewes were studied. The maternal reactivity of ewes at the outdoor lambing site was recorded in response to a human approach and to the handling of the lambs. Their behavioral reactivity was also recorded 24 h post-lambing in the arena test that involved a separation from the litter and a human presence. Flight distance, aggressive reaction, time to restore contact with the litter at the lambing site and maternal behavior scores were moderately heritable (0.18 to 0.34), and vocalizations were slightly heritable (0.16). All of these behaviors were genetically correlated with the behavioral reactivity in the arena test. The highest genetic correlations (from 0.60 to 0.90) were found for maternal behavioral scores, flight distance and high-pitched bleats. In conclusion, behavioral reactivity in the arena test can be used to assess early maternal reactivity in standardized conditions. Such phenotyping could be used for genetic improvement of maternal behavior in sheep.

Association Between Temperament Related Traits and SNPs in the Serotonin and Oxytocin Systems in Merino Sheep

Background: Animal temperament is defined as the consistent behavioural and physiological differences that are seen between individuals in response to the same stressor. Neurotransmitter systems, like serotonin and oxytocin in the central nervous system, underlie the variation in temperament in humans. The variations like single nucleotide polymorphisms (SNPs) in the genes for tryptophan 5-hydroxylase (TPH2), the serotonin transporter (SLC6A4), the serotonin receptor (HTR2A), or the oxytocin receptor (OXTR) are associated with the behavior phenotypes in human. Thus, the objective of this study was to identify SNPs in TPH2, SLC6A4, HTR2A and OXTR and to test if those variations predict the temperament of Merino sheep. Results: Using ewes from the UWA temperament flock, that has been selected on emotional reactivity for more than 20 generations, eight SNPs (rs107856757, rs107856818, rs107856856 and rs107857156 in TPH2, rs20917091 in SLC6A4, rs17196799 and rs17193181 in HTR2A, and rs17664565 in OXTR) were found to be distributed differently between calm and nervous sheep. These eight SNPs were then genotyped in 260 sheep from a non-selected flock that has never been selected on emotion reactivity, followed by the estimation of the behavioural traits of those 260 sheep using an arena test and an isolation box test. We found that several SNPs in TPH2 (rs107856757, rs107856818, rs107856856 and rs107857156) were in strong linkage disequilibrium, and all were associated with behavioural phenotype in the non-selected sheep. Similarly, rs17196799 in HTR2A was also associated with the behavioural phenotype. Conclusions: We thus conclude that, rs107856856 and rs17196799 could be used as gene markers for the temperament of Merino sheep, with allele C of rs107856856 and allele A of rs17196799 being associated with calm temperament.

Plant Acceptance for Oviposition of Tetranychus urticae on Strawberry Leaves Is Influenced by Aromatic Plants in Laboratory and Greenhouse Intercropping Experiments

The objective was to evaluate aromatic plants’ effects on the acceptance, preference, egg load, and life span of females of the twospotted spider mite (TSSM) in laboratory experiments and TSSM population under aromatic plants’ intercropping in greenhouse experiments. The pseudofruits production was also evaluated. For the laboratory, basil’s, Chinese chives’, chives’, and garlic’s influence on TSSM were tested on strawberry leaves. Four laboratory experiments were conducted: (1) Multiple choice test; (2) T-shaped arena test; (3) host–plant acceptance on aromatic plant or strawberry leaves; and (4) performance of TSSMs on strawberry leaves under aromatic plant influence. For the greenhouse experiments, assessments of the TSSM populations were realized by observing TSSM with a 10× magnifying glass on strawberry leaves in a monocrop or intercropped with Chinese chives, chives, garlic, or onion. Pseudofruit production was evaluated. Our results show that strawberry leaves were strongly preferred by TSSM. The T-shaped arena test revealed that all aromatic plants repel the TSSM. The test with the performance of TSSM females revealed that aromatic plants affected the mite’s biological parameters. Chinese chives reduced the number of eggs laid per day by 33.22%, whereas garlic reduced the number by 17.30% and chives reduced it by 12.46%. The total number of eggs was reduced by 34.79% with Chinese chives and 25.65% with garlic. Greenhouse experiments showed that chives reduced TSSM populations on two cycles and Chinese chives and garlic reduced TSSM populations on the first cycle only. With our findings, we suggest that Chinese chives, chives, and garlic are the primary candidates for intercropping use against TSSM. Chinese chives and garlic reduced the total number of eggs, but only garlic reduced female mite longevity. However, none of the intercropping plants improved strawberry pseudofruit production.

The role of personality, cognition, and affective state in same-sex contests in the red junglefowl

Intra-species contests are common in the animal kingdom and can have fitness consequences. Most research on what predicts contest outcome focuses on morphology, although differences in personality and cognition may also be involved. Supporting this, more proactive individuals often have dominant status, although the causality of this relationship is rarely investigated. Contest initiators often win; thus, individuals that are more proactive in their personality (e.g., more aggressive, risk-taking) or cognition (e.g., more optimistic, impulsive) may initiate contests more often. To investigate this, we assayed the behavior and cognition of sexually mature male and female red junglefowl (Gallus gallus), a species in which both sexes contest over social status, before staging intra-sexual contests. We confirm that contest initiators were more likely to win. In males, individuals that behaved more boldly in a novel arena test were more likely to initiate and win contests. Female initiators tended to be less active in novel object test, more aggressive in a restrained opponent test, and respond less optimistically in a cognitive judgement bias test, whereas the main predictor of whether a female would win a contest was whether she initiated it. These results suggest that behaviors attributed to proactive and reactive personalities, and—at least for female red junglefowl—optimism, can affect contest initiation and outcome. Therefore, within species, and depending on sex, different aspects of behavior and cognition may independently affect contest initiation and outcome. The generality of these findings, and their fitness consequences, requires further investigation. Significance statement In red junglefowl, we explored how behavior previously shown to describe personality, cognition, and affective state affected initiation and outcome of intra-sexual contests, by staging contests between sexually mature individuals previously assayed in behavioral and cognitive tests. In both sexes, contest initiators usually won. Bolder males were more likely to initiate and win contests. Female contests initiators were less active, more aggressive, and less optimistic. Our results suggest that personality and cognition could affect the initiation and outcome of contests and that how this occurs may differ between sexes.

Prenatal heat stress effects on gestation and postnatal behavior in kid goats

Consequences of heat stress during pregnancy can affect the normal development of the offspring. In the present experiment, 30 Murciano-Granadina dairy goats (41.8 ± 5.7 kg) were exposed to 2 thermal environments varying in temperature-humidity index (THI) from 12 days before mating to 45 days of gestation. The environmental conditions were: gestation thermal-neutral (GTN; THI = 71 ± 3); and gestation heat stress (GHS; THI = 85 ± 3). At 27 ± 4 days old, GTN-born female kids (n = 16) and GHS-born ones (n = 10) were subjected to 2 tests: arena test (AT) and novel object test (NOT), the latter was repeated at 3 months of age. Additionally, 8 months after birth, a subset of growing goats (n = 8) coming from GTN and GHS (16.8 ± 3.4 kg BW) were exposed consecutively to 2 environmental conditions: a basal thermal-neutral period (THI = 72 ± 3) for 7 days, and a heat-stress period (THI = 87 ± 2) for 21 days. In both periods, feeding behavior, resting behavior, other active behaviors (exploring, grooming), thermally-associated behaviors and posture were recorded. The gestation length was shortened by 3 days in GHS goats. In the AT, GHS kids showed a lower number of sniffs (P < 0.01) compared to GTN. In the NOT, GHS kids also tended to show a lower number of sniffs (P = 0.09). During heat exposure, GTN and GHS growing goats spent more time resting as well as exhibited more heat-stress related behaviors such as panting and drinking (P < 0.001); however, no differences were observed between both groups. In conclusion, heat stress during the first third of pregnancy shortened gestation length and influenced the exploratory behavior of the kids in the early life without impact on the behavior during the adulthood when exposed to heat stress.

Effect of Morphine Administration on Social and Non-Social Play Behaviour in Calves

The objective of this study was to evaluate the effect of morphine on social and non‐socialplay behaviour in calves. Twelve calves experienced four treatments in a cross over 2 × 2 factorialdesign: Calves received an intravenous injection of morphine or saline 10 min prior to being testedindividually or in pairs in an arena for 20 min. Play behaviour was continuously recorded in thearena test. Lying times were recorded in the home pen. Cortisol concentrations were measuredbefore and after testing. In the arena test, calves given morphine tended to perform more social playevents than calves given saline, however, morphine administration had no effect on locomotor play.Calves given morphine spent less time lying than calves given saline during the first 4 h afterreturning to the home pen. Cortisol concentrations were suppressed in calves given morphine.Administration of morphine appeared to increase social play but had no effect on locomotor playin calves. This study highlights the importance of investigating different aspects of play behaviourin animals as some may be more indicative of a positive affective state than others. More studiesinvestigating the effects of morphine on play are needed to confirm the results found in this study.