Animal Production Science
Volume 60 Number 6 2020
AN17588Do calcium and magnesium deficiencies in reproducing ewes contribute to high lamb mortality?
Lamb mortality is the largest source of reproductive wastage in sheep. This review examines potential mechanisms by which subclinical calcium or magnesium deficiencies may cause lamb mortality. Grazing ewes commonly experience subclinical deficiencies so further research is needed to clarify whether correction of these can improve lamb survival.
AN18687Estimation of genetic parameters for micro-environmental sensitivities of production traits in Holstein cows using two-step method
In the present dairy enterprise, it is beneficial for dairy cows to be strong against environmental fluctuations for important characters. Uniformity variations between animals for a given character may be depicted based on distinctions in residual variance. This heterogeneity would be applied to ameliorate robustness through selection. The aim of present study was to estimate genetic parameters for environmental sensitivities in production traits of Holstein cows. Reduction of environmental sensitivities would increase the predicted performance of animals for dairy farmers.
AN19107RNA-seq differential gene expression analysis in mammary tissue from lactating dairy cows supplemented with sunflower oil
This paper reports the effect of sunflower oil supplementation on gene expression in mammary tissue of lactating Holstein cows. Supplementation with this unsaturated fatty acid source had a strong impact on metabolism and other cellular functions in mammary tissue. It not only reduced the expression of genes associated with lipid metabolism, but also modulated genes involved in cell–cell interactions, cell morphology (organisation of the cytoskeleton), cell death and immune response.
AN18363Accuracies of direct genomic breeding values for birth and weaning weights of registered Charolais cattle in Mexico
A genomic prediction analysis of liveweight traits was performed in a Mexican Charolais cattle population. Different analytical methods were compared by their accuracy parameters. Results indicated that one method including genomic information provides slightly better accuracy than the pedigree conventional method. There are some important considerations for future genomic analyses applied to important traits considering the current industry conditions.
AN17727Animal performance, and enteric methane, manure methane and nitrous oxide emissions from Murrah buffalo calves fed diets with different forage-to-concentrate ratios
There is a growing concern over contribution and mitigation of greenhouse gases (GHG) from livestock. This experiment evaluated GHG emissions from stored faeces of calves fed diets with different roughage-to-concentrate ratios. Increasing concentrate proportion increased daily gain and reduced ruminal methane emissions but increased faecal methane and nitrous oxide production. Thus, concentrate feeding to mitigate rumen methane production should also evaluate faecal emissions.
AN18052Apparent nutrient digestibility, nitrogen metabolism and microbial protein synthesis in sheep supplemented with different vegetable fats
Using cold-pressed rapeseed or sunflower cakes, by-products of small-scale biodiesel manufacturing, as an alternative for palm fat in sheep fattening diets is a low-cost strategy that allows us to cope with the need for healthy meat products. Cold-pressed rapeseed cake can substitute palm fat without altering nutrients digestibility, nitrogen metabolism or microbial protein synthesis. The cost effectiveness of using cold-pressed sunflower cake as an alternative for palm fat, would, however, need to account for its negative effect on feed digestibility, nitrogen use efficiency and microbial protein supply to the animal.
AN18070Impacts of feeding zinc-methionine or chromium-methionine on performance, antioxidant status and physiological responses to transportation stress on lambs
For improving the performance and immune system of lambs, the use of mineral supplementation as a metabolic modifier could be an effective strategy and may reduce stress in transported animals. Road transportation of livestock, which may be an inevitable activity in animal husbandry, can be stressful to the animals. Stresses cause the alteration of growth performance and animal profitability. Addition of chromium-methionine or zinc-methionine to the diet could reduce the adverse effects of short-term transportation stress in lambs.
AN18456Dietary lycopene alters the expression of antioxidant enzymes and modulates the blood lipid profile of pigs
Lycopene protects animals against oxidative stress. The intensive pig production exposes the animals to many challenges, generating oxidative stress and compromising the health and production of pigs, that may be often reduced by using dietary antioxidants, such as lycopene. Therefore, the present study investigated the effects of dietary lycopene on pig-blood lipid profile. The study showed that gilts had a better response to dietary antioxidants than did barrows. The study showed that dietary lycopene could be used to attenuate the oxidative stress in finishing pigs, but these effects on pig health did not affect the growth performance.
AN18763Dietary zinc and growth, carcass characteristics, immune responses, and serum biochemistry of broilers
Zinc (Zn) plays an important role in many biological processes in broilers, and accurate supplementation of this mineral is the aim of the animal husbandry. Therefore, we studied the effect of dietary supplementation of Zn on the growth performance, carcass characteristics, immune responses, and serum biochemistry of the broiler chickens, and we found that supplementation of 86 mg Zn/kg in the corn–soybean meal-basal diet was appropriate. Thus, this result would provide scientific basis for broiler production.
AN19091Cover crops as alternative forages for ruminants: nutritive characteristics, in vitro digestibility, methane and ammonia production
Cover crops are used to improve soil fertility and conservation, control weeds and improve yield of follow-on crops. They may also provide alternative forages for ruminants, especially when climatic conditions limit grass supply. The objective of the present study was to assess the forage potential of different plant species commonly used as cover crops. Results showed that the tested crops hold promising nutritive quality and, thus, could be suitable as forage for ruminants.
AN18701Effects of a high-dose Saccharomyces cerevisiae inoculum alone or in combination with Lactobacillus plantarum on the nutritional composition and fermentation traits of maize silage
The inclusion of Saccharomyces in the diet of herbivores is beneficial to nutrient digestion and gut health. We explored whether the addition of a high-dose S. cerevisiae inoculum (estimated concentration 108 CFU/g) in silage production could be used to deliver viable cells. A high-dose S. cerevisiae inoculum increased the crude protein concentration of maize silage but decreased the silage quality; thus, a high-dose S. cerevisiae inoculum is not conducive to obtaining high-quality maize silage.
AN18481Sustainable goat production: modelling optimal performance in extensive systems
Growing global populations require more efficient and secure food production systems, resilient to the impacts of climate change and which minimise environmental damage. Here, a systems model is used to explore strategies for achieving greater ruminant livestock productivity in an extensive Mediterranean environment, using data collected over 3 years for goat holdings in northern Morocco, and shows that maintaining meat production is necessary to optimise performance. The model demonstrates that a diverse management strategy with a mixed meat and dairy semi-intensive production is more stable than specialised dairy systems and allows goat production and the financial viability of intensification to be maintained under climatic stress.
AN19032Post-weaning growth rate effects on body composition of Nellore bulls
Compensatory growth is described as faster than normal growth after a period of growth deprivation. However, cattle exhibiting compensatory growth have greater gain of viscera rather than carcass. Although visceral gain is important, its low economic value can impact the real economic benefit of compensatory growth for the beef industry. Our results confirmed that cattle undergoing compensatory growth might be more profitable throughout finishing, whereas it is less profitable considering the whole production system.