Marie J. Haskell

Identification of Quantitative Trait Loci Affecting Cattle Temperament

In addition to its potential contribution to improving animal welfare, the study of the genetics of cattle behavior may provide more general insights into the genetic control of such complex traits. We carried out a genome scan in a Holstein x Charolais cross cattle population to identify quantitative trait loci (QTL) influencing temperament-related traits. Individuals belonging to the second-generation of this population (F(2) and backcross individuals) were subjected to 2 behavioral tests. The flight from feeder (FF) test measured the distance at which the animal moved away from an approaching human observer, whereas the social separation (SS) test categorized different activities which the animal engaged in when removed from its penmates. The entire population was genotyped with 165 microsatellite markers. A regression interval mapping analysis identified 29 regions exceeding the 5% chromosome-wide significance level, which individually explained a relatively small fraction of the phenotypic variance of the traits (from 3.8% to 8.4%). One of the significant associations influencing an FF test trait on chromosome 29 reached the 5% genome-wide significance level. Eight other QTL, all associated with an SS test trait, reached the 1% chromosome-wide significance level. The location of some QTL coincided with other previously reported temperament QTL in cattle, whereas those that are reported for the first time here may represent general loci controlling temperament differences between cattle breeds. No overlapping QTL were identified for the traits measured by the 2 different tests, supporting the hypothesis that different genetic factors influence behavioral responses to different situations.

Genetic selection for temperament traits in dairy and beef cattle

Animal temperament can be defined as a response to environmental or social stimuli. There are a number of temperament traits in cattle that contribute to their welfare, including their response to handling or milking, response to challenge such as human approach or intervention at calving, and response to conspecifics. In a number of these areas, the genetic basis of the trait has been studied. Heritabilities have been estimated and in some cases quantitative trait loci (QTL) have been identified. The variation is sometimes considerable and moderate heritabilities have been found for the major handling temperament traits, making them amenable to selection. Studies have also investigated the correlations between temperament and other traits, such as productivity and meat quality. Despite this, there are relatively few examples of temperament traits being used in selection programmes. Most often, animals are screened for aggression or excessive fear during handling or milking, with extreme animals being culled, or EBVs for temperament are estimated, but these traits are not commonly included routinely in selection indices, despite there being economic, welfare and human safety drivers for their. There may be a number of constraints and barriers. For some traits and breeds, there may be difficulties in collecting behavioral data on sufficiently large populations of animals to estimate genetic parameters. Most selection indices require estimates of economic values, and it is often difficult to assign an economic value to a temperament trait. The effects of selection primarily for productivity traits on temperament and welfare are discussed. Future opportunities include automated data collection methods and the wider use of genomic information in selection.

Short-term temperament tests in beef cattle relate to long-term measures of behavior recorded in the home pen

Handling temperament tests for beef cattle have been related to production traits, with calmer temperaments having greater growth rates. In most tests of temperament or personality, observation of the animal takes place over a short period of time, sometimes completed in a matter of minutes. This study investigated whether behavior observed in a temperament test was reflective of the steers behavior in the home pen. Indoor-housed, crossbred, Bos taurus beef steers (n = 67) were fitted with triaxial activity monitors (IceTags; IceRobotics Ltd., South Queensferry, Edinburgh, Scotland) and activity was recorded for 2 periods of 14 d each. Also, each steer was scored on 4 measures of temperament: 2 handling tests (flight speed and chute score) and 2 feeding behavior scores (aggression at feeders and ability to displace at feeders). Each temperament observation was repeated 4 times, with repeatability of the traits ranging from 0.23 (aggression) to 0.48 (flight speed). Activity measures derived from the accelerometer data, such as bout lengths, were found to be highly repeatable between the 2 periods of activity monitoring (repeatabilities of 0.67 and 0.70 for average lying bout duration and average standing bout duration, respectively). Steers with high flight speeds were also more active in the home pen (MotionIndex: rs = 0.35, P = 0.004; average step count: rs = 0.34, P = 0.005) than steers with low flight speeds. Steers that were more capable of displacing other steers at feeders had longer average standing bout durations (rs = 0.26, P = 0.036), which were more variable (standing time SD: rs = 0.27, P = 0.030), and lay down for less time (rs = -0.35, P = 0.004). No correlations were found between aggression at feeders or chute score and home pen behavior. Results of this study are the first to demonstrate that short-term temperament tests are related to longer-term behavior data in beef steers and these results should be taken into consideration for future research.

Current trends in British dairy management regimens

This paper presents a summary of results from a 2012 survey that investigated feeding and housing management regimens currently adopted by dairy farmers in Britain. Responses from 863 farms provide a snapshot of dairy industry structure and a description of the range of management systems currently in operation. Outcomes highlight a diversity of management practices, showing that 31% of farms maintained a traditional grazing system with no forage feeding indoors during the summer, whereas 38% of farmers indicated that all their milking cows received some feeding indoors during the summer. A system of housing dairy cows for 24 h/d while they are lactating was implemented by 8% of farms, whereas 1% of farms did not house their cows at any time of the year. Statistical analyses were carried out on 3 distinct groups identified from survey responses: (1) farmers who did not undertake any indoor feeding during the summer; (2) farmers who fed all their milking cows indoors during the summer; and (3) farmers who continuously housed their cows for 24h/d while lactating. Results showed a significant relationship between management type and herd size, and between management type and breed type; on average, herd sizes were larger within systems that feed indoors. No significant relationship was found between management type and farm location when classified by estimated grassland productivity. The results indicate that traditional all-summer grazing is no longer the predominant system adopted by dairy farmers and that other systems such as all-year-round indoor feeding and continuous housing are becoming more prevalent in Britain.

Current available strategies to mitigate greenhouse gas emissions in livestock systems: an animal welfare perspective.

Livestock production is a major contributor to greenhouse gas (GHG) emissions, so will play a significant role in the mitigation effort. Recent literature highlights different strategies to mitigate GHG emissions in the livestock sector. Animal welfare is a criterion of sustainability and any strategy designed to reduce the carbon footprint of livestock production should consider animal welfare amongst other sustainability metrics. We discuss and tabulate the likely relationships and trade-offs between the GHG mitigation potential of mitigation strategies and their welfare consequences, focusing on ruminant species and on cattle in particular. The major livestock GHG mitigation strategies were classified according to their mitigation approach as reducing total emissions (inhibiting methane production in the rumen), or reducing emissions intensity (Ei; reducing CH4 per output unit without directly targeting methanogenesis). Strategies classified as antimethanogenic included chemical inhibitors, electron acceptors (i.e. nitrates), ionophores (i.e. Monensin) and dietary lipids. Increasing diet digestibility, intensive housing, improving health and welfare, increasing reproductive efficiency and breeding for higher productivity were categorized as strategies that reduce Ei. Strategies that increase productivity are very promising ways to reduce the livestock carbon footprint, though in intensive systems this is likely to be achieved at the cost of welfare. Other strategies can effectively reduce GHG emissions whilst simultaneously improving animal welfare (e.g. feed supplementation or improving health). These win-win strategies should be strongly supported as they address both environmental and ethical sustainability. In order to identify the most cost-effective measures for improving environmental sustainability of livestock production, the consequences of current and future strategies for animal welfare must be scrutinized and contrasted against their effectiveness in mitigating climate change.

Genomic data illuminates demography, genetic structure and selection of a popular dog breed

BackgroundGenomic methods have proved to be important tools in the analysis of genetic diversity across the range of species and can be used to reveal processes underlying both short- and long-term evolutionary change. This study applied genomic methods to investigate population structure and inbreeding in a common UK dog breed, the Labrador Retriever.ResultsWe found substantial within-breed genetic differentiation, which was associated with the role of the dog (i.e. working, pet, show) and also with coat colour (i.e. black, yellow, brown). There was little evidence of geographical differentiation. Highly differentiated genomic regions contained genes and markers associated with skull shape, suggesting that at least some of the differentiation is related to human-imposed selection on this trait. We also found that the total length of homozygous segments (runs of homozygosity, ROHs) was highly correlated with inbreeding coefficient.ConclusionsThis study demonstrates that high-density genomic data can be used to quantify genetic diversity and to decipher demographic and selection processes. Analysis of genetically differentiated regions in the UK Labrador Retriever population suggests the possibility of human-imposed selection on craniofacial characteristics. The high correlation between estimates of inbreeding from genomic and pedigree data for this breed demonstrates that genomic approaches can be used to quantify inbreeding levels in dogs, which will be particularly useful where pedigree information is missing.

Changes in feed intake during isolation stress in respiration chambers may impact methane emissions assessment

Respiration chambers are considered the ‘gold standard’ technique for measuring in vivo methane (CH4) emissions in live animals. However, the imposed isolation required may alter feeding behaviour and intake, which ultimately impact CH4 emissions. The aim of this study was to assess the impact of isolation within respiration chambers on feed intake and CH4 emissions with two different diets and breeds of beef cattle. In addition, a routine stressor (transport) was used to examine the relationship between individual stress responsiveness and changes in feed intake during isolation. Eighty-four steers (castrated males) (569 ± 5.7 kg bodyweight, BW) were divided into two groups and each group fed with one of two basal diets consisting of (g/kg dry matter, DM) either 50u2009:u200950 (Mixed) or 8u2009:u200992 (Concentrate) forage to concentrate ratios. Within each basal diet there were three supplementation treatments: (1) control, (2) calcium nitrate, and (3) rapeseed cake. The stress biomarkers plasma cortisol, creatine kinase (CK), and free fatty acids (FFA) were determined before (0 h) and after (30 min, 3 h, 6 h and 9 h) a 30-min journey, when steers were transported to the respiration chamber facilities. Methane emissions were measured over a 3-day period using individual respiration chambers. Dry matter intake (DMI) was assessed within the group-housed pens (4 weeks before entry to training pen), in the training pens and the chambers. Cortisol, FFA and CK increased (P < 0.05) after transport confirming a stress response. DMI (g/kg BW) decreased (P < 0.001) during isolation in the training pens (14.7 ± 0.28) and the chambers (14.3 ± 0.26) compared with that of the same animals in the group pens (16.8 ± 0.23). DMI during isolation decreased more in those animals which had an increased (P < 0.05) stress response during transport as measured by cortisol, FFA and CK. With the Mixed diet, the decline in DMI was estimated to result in an increase in CH4 (g/kg DMI) (r = 0.25, P = 0.001), which did not occur with the Concentrate diet. According to the results of this experiment, the stress associated with isolation reduces the DMI resulting in an increase in g CH4/kg DMI in fibrous diets. Habituation to isolation needs refinement in order to reduce the impact of stress on intake and therefore achieve more accurate estimates of CH4 emissions. Alternatively, modelling CH4 estimations according to behavioural and physiological changes associated with isolation stress would improve accuracy of CH4 estimations.

Association of Temperament and Acute Stress Responsiveness with Productivity, Feed Efficiency, and Methane Emissions in Beef Cattle: An Observational Study

The aim of this study was to assess individual differences in temperament and stress response and quantify their impact on feed efficiency, performance, and methane (CH4) emissions in beef cattle. Eighty-four steers (castrated males) (Charolais or Luing) were used. Temperament was assessed using two standardized tests: restlessness when restrained [crush score (CS)] and flight speed (FS) on release from restraint. Over a 56-day period individual animal dry matter intake (DMI) and weekly body weight was measured. Ultrasound fat depth was measured at the end of 56u2009days. Average daily gain (ADG), feed conversion ratio (FCR), and residual feed intake (RFI) were calculated. After the 56-day test period, animals were transported in groups of six/week to respiration chamber facilities. Blood samples were taken before and 0, 3, 6, and 9u2009h after transport. Plasma cortisol, creatine kinase (CK), glucose, and free fatty acids (FFA) were determined to assess physiological stress response. Subsequently, CH4 emissions were measured over a 3-day period in individual respiration chambers. CS (1.7u2009±u20090.09) and FS (1.6u2009±u20090.60u2009m/s) were repeatable (0.63 and 0.51, respectively) and correlated (ru2009=u20090.36, Pu2009<u20090.001). Plasma cortisol, CK, and FFA concentrations increased after transport (Pu2009=u20090.038, Pu2009=u20090.006, and Pu2009<u20090.001, respectively). Temperament (CS) and CK concentration were correlated (ru2009=u20090.29; Pu2009=u20090.015). The extreme group analysis reveals that excitable animals (FS; Pu2009=u20090.032) and higher stress response (cortisol, Pu2009=u20090.007; FFA, Pu2009=u20090.007; and CK, Pu2009=u20090.003) were associated with lower DMI. ADG was lower in more temperamental animals (CS, Pu2009=u20090.097, and FS, Pu2009=u20090.030). Fat depth was greater in steers showing calmer CS (Pu2009=u20090.026) and lower plasma CK (Pu2009=u20090.058). Temperament did not show any relationship with RFI or CH4 emissions. However, steers with higher cortisol showed improved feed efficiency (lower FCR and RFI) (Pu2009<u20090.05) and greater CH4 emissions (Pu2009=u20090.017). In conclusion, agitated temperament and higher stress responsiveness is detrimental to productivity. A greater stress response is associated with a reduction in feed intake that may both increase the efficiency of consumed feed and the ratio of CH4 emissions/unit of feed. Therefore, temperament and stress response should be considered when designing strategies to improve efficiency and mitigate CH4 emissions in beef cattle.

Genetic characterization of dog personality traits

The genetic architecture of behavioral traits in dogs is of great interest to owners, breeders, and professionals involved in animal welfare, as well as to scientists studying the genetics of animal (including human) behavior. The genetic component of dog behavior is supported by between-breed differences and some evidence of within-breed variation. However, it is a challenge to gather sufficiently large datasets to dissect the genetic basis of complex traits such as behavior, which are both time-consuming and logistically difficult to measure, and known to be influenced by nongenetic factors. In this study, we exploited the knowledge that owners have of their dogs to generate a large dataset of personality traits in Labrador Retrievers. While accounting for key environmental factors, we demonstrate that genetic variance can be detected for dog personality traits assessed using questionnaire data. We identified substantial genetic variance for several traits, including fetching tendency and fear of loud noises, while other traits revealed negligibly small heritabilities. Genetic correlations were also estimated between traits; however, due to fairly large SEs, only a handful of trait pairs yielded statistically significant estimates. Genomic analyses indicated that these traits are mainly polygenic, such that individual genomic regions have small effects, and suggested chromosomal associations for six of the traits. The polygenic nature of these traits is consistent with previous behavioral genetics studies in other species, for example in mouse, and confirms that large datasets are required to quantify the genetic variance and to identify the individual genes that influence behavioral traits.

Valence of facial cues influences sheep learning in a visual discrimination task

Sheep are one of the most studied farm species in terms of their ability to process information from faces, but little is known about their face-based emotion recognition abilities. We investigated (a) whether sheep could use images of sheep faces taken in situation of varying valence as cues in a simultaneous discrimination task and (b) whether the valence of the situation affects their learning performance. To accomplish this, we photographed faces of sheep in three situations inducing emotional states of neutral (ruminating in the home pen) or negative valence (social isolation or aggressive interaction). Sheep (nu2009=u200935) first had to learn a discrimination task with colored cards. Animals that reached the learning criterion (nu2009=u200916) were then presented with pairs of images of the face of a single individual taken in the neutral situation and in one of the negative situations. Finally, sheep had to generalize what they had learned to new pairs of images of faces taken in the same situation, but of a different conspecific. All sheep that learned the discrimination task with colored cards reached the learning criterion with images of faces. Sheep that had to associate a negative image with a food reward learned faster than sheep that had to associate a neutral image with a reward. With the exception of sheep from the aggression-rewarded group, sheep generalized this discrimination to images of faces of different individuals. Our results suggest that sheep can perceive the emotional valence displayed on faces of conspecifics and that this valence affects learning processes.