Dwyer C.M.,Animal and Veterinary science Research Group
Animal | Year: 2014
Parental care promotes offspring survival and, for livestock species, this care is provided solely by the mother. Maternal behaviour in the sheep has been exceptionally well-studied compared with other species and many of the underpinning biological processes leading to the expression of maternal care are known. In this review the current state of play with regard to the biology of maternal care will be reviewed, and its application to provide practical solutions to reduce lamb mortality considered. For maternal care to be elicited at birth the ewe requires elevated circulating oestradiol in late gestation, which stimulates the expression of oxytocin receptors in both peripheral and central areas (particularly the hypothalamic and limbic areas of the brain). At birth stretching of the vaginocervical canal elicits a spinal reflex which triggers the release of oxytocin primarily from neurones within the paraventricular nucleus of the hypothalamus. Oxytocin release causes an increase in the neurotransmitters noradrenaline, acetylcholine, glutamate and γ-aminobutyric acid (GABA) in the olfactory bulb, and other brain regions important for maternal behaviour. Finally, sensory cues provided by the lamb, in particular the amniotic fluids surrounding it, lead to the expression of maternal behaviours (licking, low-pitched bleats, acceptance of the lamb at the udder and suckling). This allows the expression of the two facets of maternal behaviour in the ewe: nurturance of the young and maternal selectivity, whereby a specific olfactory memory for the ewes own lamb is formed and the expression of maternal care is restricted to this lamb. Variation in the expression of maternal care has been demonstrated in primiparous ewes compared with multiparous, in different sheep genotypes, with undernutrition, stress in pregnancy, following a difficult delivery, and may occur with variation in ewe temperament. An understanding of the importance of the timing of various events in late pregnancy and during parturition, as well as the factors that can disrupt these events, can help to design management activities to minimise risks to the successful onset of maternal behaviour. Management practices that work with the biology of the ewe will be the most successful in ensuring that maternal care is expressed, so improving the welfare of the ewe and lamb, and the profitability of the farm. Copyright © The Animal Consortium 2013.
Chan Y.F.,Max Planck Institute for Evolutionary Biology |
Jones F.C.,Stanford University |
McConnell E.,Max Planck Institute for Evolutionary Biology |
Bryk J.,Max Planck Institute for Evolutionary Biology |
And 2 more authors.
Current Biology | Year: 2012
Understanding how polygenic traits evolve under selection is an unsolved problem , because challenges exist for identifying genes underlying a complex trait and understanding how multilocus selection operates in the genome. Here we study polygenic response to selection using artificial selection experiments. Inbred strains from seven independent long-term selection experiments for extreme mouse body weight ("high" lines weigh 42-77 g versus 16-40 g in "control" lines)  were genotyped at 527,572 SNPs to identify loci controlling body weight. We identified 67 parallel selected regions (PSRs) where high lines share variants rarely found among the controls. By comparing allele frequencies in one selection experiment [2-4] against its unselected control, we found classical selective sweeps centered on the PSRs. We present evidence supporting two G protein-coupled receptors GPR133 and Prlhr as positional candidates controlling body weight. Artificial selection may mimic natural selection in the wild: compared to control loci, we detected reduced heterozygosity in PSRs in unusually large wild mice on islands. Many PSRs overlap loci associated with human height variation , possibly through evolutionary conserved functional pathways. Our data suggest that parallel selection on complex traits may evoke parallel responses at many genes involved in diverse but relevant pathways. © 2012 Elsevier Ltd.
Dixon L.M.,Animal and Veterinary science Research Group |
Sparks N.H.C.,Avian Science Research Center |
Rutherford K.M.D.,Animal and Veterinary science Research Group
Poultry Science | Year: 2016
Early life experiences can be important in determining offspring phenotypes and may influence interaction with the environment and hence health, welfare, and productivity. The prenatal environment of poultry can be divided into the pre-lay environment and the egg storage/incubation environment, both of which can affect offspring outcomes. The ability to separate maternal and egg/incubation effects makes birds well suited to this type of research. There are many factors, including feeding and nutrition, environmental conditions, husbandry practices, housing system, social environment, infectious environment, and maternal health status, that can influence both the health and performance and behavior and cognition of the offspring. There are some aspects of the environments that can be changed to produce beneficial effects in the offspring, like addition of certain additives to feed or short changes in incubation temperatures, while other aspects should be avoided to reduce negative effects, such as unpredictable feeding and lighting regimens. Measures of offspring characteristics may prove to be a useful method of assessing parent stock welfare if known stressors result in predictable offspring outcomes. This has the advantage of assessing the parent environment without interfering with the animals and possibly affecting their responses and could lead to improved welfare for the animals. © 2016 The Author 2015. Published by Oxford University Press on behalf of Poultry Science Association.
Clark C.C.A.,Animal and Veterinary science Research Group |
D'Eath R.B.,Animal and Veterinary science Research Group
Applied Animal Behaviour Science | Year: 2013
Excessive aggression between pigs at mixing is a welfare and production issue resulting in stress, injuries and economic losses. If it can be demonstrated that aggression is a consistent behaviour trait, it might provide a means to reduce these losses. To test for consistency of aggressiveness, 163 male and female damline pigs, mixed at weaning (mean ± SD day = 33.7 ± 3.4), were given resident-intruder tests (RITs) on successive days (test pairs a and b) on up to three occasions: day 60 (test 1); day 95 (test 2); and day 130 (test 3). Pigs tested at all three time points (T123 n= 90) showed consistency in occurrence of attacking within (a vs. b) and between tests (1 vs. 2, 2 vs. 3 and 1 vs. 3), suggesting that aggressiveness is a moderately stable temperament trait. Compared to previous studies of this kind there were clear differences between male and female pigs, with a higher than expected rate of mounting in male pigs. Mounting also appeared to be a consistent trait, beginning from a surprisingly early age (day 60). Latency to attack decreased in the female pigs (n= 53) after test 1a, but did not change after this, although a further unexpected finding, was an effect of boar line on the occurrence of attacking in female pigs. In the male pigs (n= 37) aggression reduced over time, which we propose was primarily as a result of increased mounting. Sex differences in aggression and mounting were also seen when the behaviour of pigs naive to the RIT were first tested (test 1, treatments T123, n= 90 and T13, n= 22; test 2 T23, n= 24; test 3, T3, n= 27), suggesting they result from age rather than experience. The effect of prior RIT experience on aggression in the final test (test 3) was examined in terms of: (1) the amount of experience, by comparing pigs with no (T3), one (T23 and T13) or two (T123) previous experiences of the RIT; and (2) the age at first experience, by comparing pigs first tested in test 1 (T13) or test 2 (T23). Prior RIT experience made little difference to the level of aggression (attack latency), although more experienced pigs were more likely to attack than to mount. In conclusion, pigs showed stable individual differences in both aggression and mounting, which were affected more by sex and age than by prior test experience. © 2013 Elsevier B.V.
Murray L.M.A.,University of Edinburgh |
Murray L.M.A.,Animal and Veterinary science Research Group |
Byrne K.,University of Edinburgh |
D'Eath R.B.,Animal and Veterinary science Research Group
Applied Animal Behaviour Science | Year: 2013
Pair and social bonding has been documented in various taxa, where pair formations are often described as being driven by kinship or sexual motivation. However, pair-bonding between unrelated individuals where sexual motivation is not a factor is not well documented. Many social relationships and pair-bonds between members of a dyad are facilitated by each individual's ability to recognise their partner using cues which are characteristic of that particular individual. The aims of this study were i) to investigate the existence of pair-bonding in domestic donkeys and ii) to determine whether members of a dyad could recognise their companion during a Y-maze recognition test. Subjects were 55 unrelated donkeys (38 gelded males, 15 females) in seven groups of mixed or same sex, comprising 4-14 individuals. Spatial proximity (nearest-neighbour) was observed three times a day over a 22-day period. Using a simulation approach based on observed data to generate randomised nearest-neighbour matrices, the statistical significance of social relationships was estimated. Of these, 42 (79.2%) were involved in significantly (P<0.05) non-random nearest-neighbour relationships, most of which were reciprocal pair relationships. Based on the spatial data, 24 of the donkeys which had shown significant reciprocal nearest-neighbour preferences for one individual (companion) were then used in a Y-maze recognition test in which they were presented with a choice of their companion and either a familiar donkey from the same group or an unfamiliar donkey from a different group. Donkeys' spatial location in the Y-maze demonstrated a preference for their companion versus familiar (one sample Wilcoxon signed rank test, W=239, p=0.002) or unfamiliar donkeys (W=222, p=0.041). These results verify anecdotal evidence from donkey handlers that donkeys often form pair-bonds, and show that reciprocal social preference and recognition are the basis of these. Pair-bond formation and companionship among donkeys have potential implications for their management, husbandry and welfare. © 2012 Elsevier B.V..