Gene expression patterns in four brain areas associate with quantitative measure of estrous behavior in dairy cows

<p>Abstract</p> <p>Background</p> <p>The decline noticed in several fertility traits of dairy cattle over the past few decades is of major concern. Understanding of the genomic factors underlying fertility, which could have potential applications to improve fertility, is very limited. Here, we aimed to identify and study those genes that associated with a key fertility trait namely estrous behavior, among genes expressed in four bovine brain areas (hippocampus, amygdala, dorsal hypothalamus and ventral hypothalamus), either at the start of estrous cycle, or at mid cycle, or regardless of the phase of cycle.</p> <p>Results</p> <p>An average heat score was calculated for each of 28 primiparous cows in which estrous behavior was recorded for at least two consecutive estrous cycles starting from 30 days post-partum. Gene expression was then measured in brain tissue samples collected from these cows, 14 of which were sacrificed at the start of estrus and 14 around mid cycle. For each brain area, gene expression was modeled as a function of the orthogonally transformed average heat score values using a Bayesian hierarchical mixed model. Genes whose expression patterns showed significant linear or quadratic relationships with heat scores were identified. These included genes expected to be related to estrous behavior as they influence states like socio-sexual behavior, anxiety, stress and feeding motivation (<it>OXT, AVP, POMC, MCHR1</it>), but also genes whose association with estrous behavior is novel and warrants further investigation.</p> <p>Conclusions</p> <p>Several genes were identified whose expression levels in the bovine brain associated with the level of expression of estrous behavior. The genes <it>OXT </it>and <it>AVP </it>play major roles in regulating estrous behavior in dairy cows. Genes related to neurotransmission and neuronal plasticity are also involved in estrous regulation, with several genes and processes expressed in mid-cycle probably contributing to proper expression of estrous behavior in the next estrus. Studying these genes and the processes they control improves our understanding of the genomic regulation of estrous behavior expression.</p

Northern fowl mite infestation affects the nocturnal behavior of laying hens

The northern fowl mite (Ornithonyssus sylviarum) is a key pest for caged laying hens. High infestation levels can lead to anemia, reduced production, and mortality. Although the mites cause skin irritation and thus likely affect resting behavior, the nocturnal behavior of infested chickens has not yet been studied. We investigated the impact of mite infestation on nighttime behavior of 16 beak-trimmed White Leghorn hens. The hens were housed individually in wire cages. They were experimentally inoculated with approximately 35 mites at 25 weeks of age and observed for the behaviors dozing, sleeping, preening and being active. Continuous observations were made from video recordings taken from 22:00 h until 06:00 h for two consecutive nights at pre-infestation week 0 and post-infestation weeks 3, 5 and 7. Mite infestation levels were measured weekly on an 8-point scale (0 (no mites) to 7 (≥10,000 mites per hen)). For statistical analyses with linear mixed models, mite infestation levels were categorized as score 0 (no mites), 3–4 (51–500), 5 (501–1000) and 6–7 (>1000). Higher levels of mite infestation were associated with hens spending less time dozing (P < 0.001) and more time preening (P < 0.001) and being active (P = 0.012). Dozing decreased from 90% of the observed time for mite score 0 to 76% for score 6–7. Preening increased from 2% (score 0) to 9% (6–7) and time spent being active increased from 1% (0) to 7% (6–7). Mite infestation increased the number of uninterrupted bouts of all behaviors (P ≤ 0.020), especially dozing and preening (P < 0.001), suggesting restlessness in the mite-infested hens due to irritation and itching. The mite-infested hens’ increased nocturnal activity, including preening, as well as the fragmentation of behavioral activities together with decreased dozing, indicate disturbed resting behavior and suggest a reduction in the welfare of mite-infested hens.</p

Behavioural testing based breeding policy reduces the prevalence of fear and aggression related behaviour in Rottweilers

Behavioural testing allows to exclude dogs that are fearful and aggressive from the breeding population, but relatively little is known about the effectiveness of such strategies in practice. From 2001 till 2009 parent purebred Dutch Rottweilers had to pass the Socially Acceptable Behaviour (SAB)-test for their offspring to obtain a pedigree certificate. We evaluated if this breeding policy of excluding fearful and aggressive Rottweilers, as diagnosed by the SAB-test, indeed reduced the prevalence of fear and aggression in the Dutch Rottweiler population. Owner-reported assessments of their dogs' behaviour were compared between groups of Rottweilers with or without pedigree certificates, assuming the Rottweiler look-a-likes to represent the control condition of no breeding policy regarding fear and aggression. A total of 822 Rottweiler owners filled out the Canine Behavioural Assessment and Research Questionnaire (C-BARQ) on problem behaviour, including 7 behavioural categories related to fear and aggression. Problem behaviour prevalence and explanatory factors were investigated by multivariable logistic regression.The prevalence of Stranger-directed fear (P. <. 0.05) and Non-social fear (P. <. 0.01) was lower in the group of pedigrees than in the group of look-a-likes, with a same tendency for Stranger-directed aggression (P = 0.056). Analysing the combined C-BARQ scores for the behaviour categories that are assessed with the SAB-test, namely Stranger-directed aggression, Dog-directed fear/aggression, Stranger-directed fear and Non-social fear, revealed that one sixth of the pedigree Rottweilers showed these behaviours compared to one third of the look-a-likes (P. <. 0.0001). Strong associations were found between Stranger-directed aggression and Dog-directed fear/aggression (P. <. 0.001) or Social Fear (P. <. 0.001), indicating the role of fear in aggression towards unfamiliars. The association between Stranger-directed aggression and chase proneness (P. <. 0.01) seems to illustrate how different motivations may underlie a same manifestation of aggression. Familiar dog aggression associated with Owner-directed aggression (P. <. 0.001), implicating that such aggressions may have do with conflicts over status. Found associations between types of fear/aggression will have in part reflected shared underlying causes, and reflect the known comorbidity of problem behaviours. Their associations with dog and/or owner characteristics indicated several possible risk factors for fear/aggression. However, associations with common risk factors like sex and reproductive status were not found.Taking into account behaviour test outcomes in Rottweiler pedigree certification was associated with a reduced prevalence of fear and aggression. The exclusion of fear/aggressive individuals from the breeding population on the basis of SAB-test outcomes may have had favourable effects on population genetics or incited preventive actions by breeders like not putting a dog forward for pedigree certification. In our view, validated behaviour tests like the SAB-test can help to reduce unwanted behaviours in dog populations by breeding policies.</p

Desexing dogs as a means of decreasing the generally regarded sexually dimorphic behaviors of urine marking, mounting, and roaming

Desexing (castrating, ovariectomizing/neutering) and a dog's sex are topics of relevance to many dog owners. We studied the relationship between desexing and three behaviors that are presumed sexually dimorphic, that is, differ in occurrence between the sexes. Urine marking, mounting, and roaming were used as models for studying the effects of desexing on (unwanted) behavior in dogs. We assessed the relationships between the occurrences of the three behaviors and the four factors of the dogs’ sex, sexual status, desexing age, and age in general. A convenience sample of dog owner reports was collected with an online survey and 982 records were analyzed with Chi-square tests. Counts were expressed in cross- tables of the behavior being present or absent and one of the aforementioned four factors. Urine marking occurred most frequently in intact male dogs (78%, N = 188), with significant differences compared with intact females (41%, N = 48; P 8 years) and roaming (46%, N = 34 of the dogs8 years). Such differences were not found for females or for urine marking in males. Mounting and roaming occurring less often in older male dogs suggest that these behaviors may decrease with age, naturally or through other factors. Our cross-sectional study shares with many earlier studies that its setup does not establish causal effects of desexing and we recommend large-scale prospective studies as a next step in providing scientific evidence for how behavior is affected by desexing. More knowledge of the influence of sex hormones on behavior in dogs is needed to support decisions on desexing individual dogs for reasons of unwanted behavior, which will benefit both the dogs and their owners

Self-reports of Dutch dog owners on received professional advice, their opinions on castration and behavioural reasons for castrating male dogs

Male dogs are often castrated based on the thought that it facilitates well-behavedness. However, the causal evidence for this from prospective studies lacks and the existing associative studies present mixed results depending on the studied behaviours. We aimed to gain insight into possible factors driving an owner's decision to castrate their male dog, through a quantitative survey based on a convenience sample. We determined the advice owners received from three types of dog professionals (veterinarian practitioners, behavioural trainers, behavioural therapists) and the owners' assessments of castration's behavioural effects. Data on 491 Dutch owners of castrated and intact male dogs were analysed with Chi-square tests. Results indicate that owners of both castrated and intact dogs received castration advice most often from veterinarian practitioners, with pro-castration at higher frequencies for owners of castrated dogs (Chi-square, P<0.001). Overall, most owners disagreed with or were neutral about statements on castration positively affecting male dog behaviour at a population level. Nevertheless, 58% (N = 145) of the owners of castrated dogs (N = 249) reported that correcting unwanted behaviour was a reason to castrate their own male dog. Unwanted behaviour involved aggression in 50% (N = 70) of the owner-dog dyads. Castrated dog's aggression changes were reported on most as 'no change'. The second most common answer indicated an aggression decrease in dogs castrated to correct unwanted behaviour and an increase in dogs castrated for other reasons (Chi-square, P<0.001). The increase in aggression in a subset of castrated dogs is concerning, as aggression can pose risks to the dog's welfare. We acknowledge the limitations of our study which identifies associations rather than provides causal evidence. Still, we recommend professionals' awareness of possible negative behavioural changes following castration, like increased aggression. Future research on behavioural consequences of castrating dogs needs to build a more solid knowledge base for balanced advice regarding castration.</p

The Use of Saliva Cortisol, Urinary Cortisol, and Catecholamine Measurements for a Noninvasive Assessment of Stress Responses in Dogs

A problem in assessing animal welfare is that collecting data in itself may be stressful to the animals. Therefore, noninvasive methods for collecting data have to be devised and tested. A first step in investigating saliva cortisol, urinary cortisol, and urinary catecholamine as noninvasive indicators of canine well-being is the validation of these hormonal measures as alternatives for those in plasma. Using a model of insulin (0.2 U/kg)-induced hypoglycemia, we report on stress-induced responses in saliva cortisol, urinary cortisol, and urinary catacholamines relative to cortisol and catecholamine responses in plasma. Hypoglycemia in six dogs induced significant (P\u3c 0.05) increases in plasma cortisol and adrenaline but not noradrenaline. Saliva cortisol responses expressed as net area under the response curve correlated significantly with plasma cortisol responses (r\u3e 0.92). Saliva cortisol levels measured 7 to 12% of plasma cortisol concentrations. Cortisol/creatinine ratios in urine were significantly higher when voided after insulin administeration, compared to when voided after saline treatment. Insulin-induced increments in cortisol/creatinine ratios were nonsignificant when urine samples were assayed after dichloromethane extraction. Although urinary adrenaline/creatinine (A/C) ratios were significantly correlated with maximum plasma adrenaline values after insulin administration, A/C ratios did not differ significantly between insulin and saline treatment. The present experiment provides strong support for using saliva sampling and urine collection as noninvasive methods to establish stress-induced cortisol responses. For measuring acute plasma adrenaline responses, measuring A/C ratios may not be a valid alternative

The Use of Saliva Cortisol, Urinary Cortisol, and Catecholamine Measurements for a Noninvasive Assessment of Stress Responses in Dogs

A problem in assessing animal welfare is that collecting data in itself may be stressful to the animals. Therefore, noninvasive methods for collecting data have to be devised and tested. A first step in investigating saliva cortisol, urinary cortisol, and urinary catecholamine as noninvasive indicators of canine well-being is the validation of these hormonal measures as alternatives for those in plasma. Using a model of insulin (0.2 U/kg)-induced hypoglycemia, we report on stress-induced responses in saliva cortisol, urinary cortisol, and urinary catacholamines relative to cortisol and catecholamine responses in plasma. Hypoglycemia in six dogs induced significant (P\u3c 0.05) increases in plasma cortisol and adrenaline but not noradrenaline. Saliva cortisol responses expressed as net area under the response curve correlated significantly with plasma cortisol responses (r\u3e 0.92). Saliva cortisol levels measured 7 to 12% of plasma cortisol concentrations. Cortisol/creatinine ratios in urine were significantly higher when voided after insulin administeration, compared to when voided after saline treatment. Insulin-induced increments in cortisol/creatinine ratios were nonsignificant when urine samples were assayed after dichloromethane extraction. Although urinary adrenaline/creatinine (A/C) ratios were significantly correlated with maximum plasma adrenaline values after insulin administration, A/C ratios did not differ significantly between insulin and saline treatment. The present experiment provides strong support for using saliva sampling and urine collection as noninvasive methods to establish stress-induced cortisol responses. For measuring acute plasma adrenaline responses, measuring A/C ratios may not be a valid alternative

Rein sensor leash tension measurements in owner-dog dyads navigating a course with distractions

Consistent owner-dog interaction patterns such as dog-directed parenting styles could reflect in the leash tension applied when walking a dog. Rein sensors are commonly used to measure tension applied to a horse's bit and our research aim was to evaluate the performance of this methodology for measuring leash tension. We evaluated the consistency of leash tension measurements in owner-dog dyads walking a food-distraction course and a more complex zigzag object-distraction course to confirm our prediction that the more challenging course would trigger increased leash tension. Leash tension sample points were averaged per owner-dog dyad per course, and we used restricted maximum likelihood to analyze leash tensions for effects of course difficulty and dog body weight. In 24 participating owner-dog dyads, leash tension was an average (±standard deviation) 18.29 ± 14.03 newtons. Leash tensions were 1.6 times higher (P < 0.001) during the more challenging second course than during the easier first one and variation between owner-dog dyads was consistent across the two courses (rank correlation of 0.63, P = 0.001, N = 24). Our findings support the usefulness of rein sensors for measuring leash tension, with potential applications in studies on the owner-dog relationship such as how leash exerted levels of control relate to dog-directed parenting styles.</p

Dog ownership satisfaction determinants in the owner-dog relationship and the dog’s behaviour

Dog ownership satisfaction relates to the quality of life of both owner and dog, and when seriously compromised may even lead to dog abandonment. Knowledge on determinants of dog ownership satisfaction is limited, obstructing solutions for promoting satisfaction, and here we quantified causes making dog owners less than very satisfied with their dog. We focused on the owner perceived relationship with the dog, unwanted dog behaviour, and dog obedience class attendance. The study population included only few seriously dissatisfied dog owners, preventing discrimination of multiple levels below ‘very satisfied’. Consequently, existing relationships in the entire population may have been missed or underestimated and the findings apply specifically to dog owners that are relatively contented with dog ownership. Nine hundred seventy-seven Dutch dog owners completed an online questionnaire and we found the probability of being very satisfied to associate with all three subscales of the Monash Dog Owner Relationship Scale. Most strongly with perceived costs of ownership and less so with shared activities between owner and dog, and perceived emotional closeness to the dog. Aggression and/or disobedience related directly to high perceived ownership costs and to an increased probability of being less than very satisfied. Interaction effects indicated that dog disobedience was less influential on ownership satisfaction at high levels of aggression. Surprisingly, dog ownership satisfaction was unrelated to dog obedience class attendance, raising questions about the effectiveness of these classes in establishing satisfying dog-owner relationships. Training aids used during classes could play a role here, as choke chain use associated with high perceived costs and increased probabilities of being less then very satisfied with dog ownership. Ownership satisfaction in relatively contented dog owners, seems more influenced by unwanted dog behaviour and perceived costs of ownership, than by perceived emotional closeness to the dog, shared activities and dog obedience class attendance.</p