Behavioural and physiological responses of individually housed dairy calves to change in milk feeding frequency at different ages

peer reviewedThis study aimed to use a range of non-invasive monitoring technologies to investigate the behavioural and physiological responses of individually housed dairy calves to age at change in milk replacer (MR) feeding frequency. Forty-eight Holstein Friesian calves were individually penned and fed MR (625 g/d) as solids in one of three feeding regimes: (i) once-a-day feeding commencing at age 14 d (OAD14), (ii) once-a-day feeding commencing at age 28 d (OAD28) and (iii) twice-a-day feeding (TAD). Several behavioural (automatic activity sensors), physiological (infrared [IR] thermography and heart rate variability [HRV]) and haematological indicators were used to examine calf responses. Reduction in milk feeding frequency at 14 or 28 d of age increased daily concentrate intakes and drinking water consumption throughout the pre-wean period. Calf lying behaviour was unaffected by reduction in milk feeding frequency; however, TAD calves recorded a significant decrease in total daily lying time during the post-wean period compared with OAD28s. There was no effect of treatment on IR eye or rectal temperature throughout the experiment; however, there was an effect of age, with IR temperature decreasing as calf age increased. OAD14 calves tended to have decreased HRV at days 14 and 16, which is suggestive of an increased stress load. The findings suggest that under high levels of animal husbandry and whilst maintaining the same amount of milk powder/d (625 g/d), reduction in milk feeding frequency from twice to once daily at 28 d can occur without significant impact to behavioural, performance and physiological parameters assessed here

Influences of Domestication and Island Evolution on Dental Growth in Sheep

Funder: Department of Zoology, University of CambridgeFunder: Leverhulme Trust; doi: http://dx.doi.org/10.13039/501100000275Abstract: Domestication and island evolution can lead to changes of life history along the slow-fast gradient. Shifts of life history patterns, in turn, are potentially related to alterations of patterns and timing of tooth eruption. Schultz’s rule predicts an earlier eruption of molars relative to premolars as fecundity increases during the domestication process. On the other hand, evolution on a predator-free, resource limited island might lead to a generally slow life history and delayed tooth eruption, as in the Plio-Pleistocene Balearic caprine Myotragus. In this study, we investigate tooth eruption and its relation to life history in a unique sheep population that is an example of both domestication and island evolution: the ancient and feral Soay sheep (Ovis aries) of the St. Kilda archipelago, Scotland. Tooth eruption timing and sequence is investigated in a comparative framework featuring new data on other domestic sheep (O. aries), including European mouflon (O. a. musimon), as well as wild sheep (O. vignei, O. cycloceros, O. arkal, O. orientalis, O. ammon). These data indicate that the order of eruption is similar in wild and domestic sheep, despite the fundamental life history changes that came about with domestication. However, in contrast to other domestic sheep breeds, Soay sheep erupt their teeth at an absolute older age and also tend to grow more slowly, which resembles the evolutionary trend in island-adapted Myotragus. Despite these similarities, Soay sheep do not share the slow life history pattern inferred for Myotragus, highlighting the distinctive nature of tooth eruption in Soay sheep

Non-invasive metabolomics biomarkers of production efficiency and beef carcass quality traits.

The inter-cattle growth variations stem from the interaction of many metabolic processes making animal selection difficult. We hypothesized that growth could be predicted using metabolomics. Urinary biomarkers of cattle feed efficiency were explored using mass spectrometry-based untargeted and targeted metabolomics. Feed intake and weight-gain was measured in steers (n = 75) on forage-based growing rations (stage-1, 84 days) followed by high-concentrate finishing rations (stage-2, 84 days). Urine from days 0, 21, 42, 63, and 83 in each stage were analyzed from steers with the greater (n = 14) and least (n = 14) average-daily-gain (ADG) and comparable dry-matter-intake (DMI; within 0.32 SD of the mean). Steers were slaughtered after stage-2. Adjusted fat-thickness and carcass-yield-grade increased in greater-ADG-cattle selected in stage-1, but carcass traits did not differ between ADG-selected in stage-2. Overall 85 untargeted metabolites segregated greater- and least-ADG animals, with overlap across diets (both stages) and breed type, despite sampling time effects. Total 18-bile acids (BAs) and 5-steroids were quantified and associated with performance and carcass quality across ADG-classification depending on the stage. Stepwise logistic regression of urinary BA and steroids had > 90% accuracy identifying efficient-ADG-steers. Urine metabolomics provides new insight into the physiological mechanisms and potential biomarkers for feed efficiency