Animal Production Science
Volume 60 Number 8 2020
AN19437Application of exogenous enzymes: is digestibility an appropriate response variable?
Phytases, carbohydrases and proteases are key animal feed products used to improve feed efficiency and nutrient utilisation and reduce environmental waste. Studies evaluating enzyme efficacy in pigs and poultry rely on nutrient digestibility results to highlight the nutrient sparing effects of the enzyme or enzyme combination. Here we highlight the challenges associated with digestibility assays and show that results do not always correspond to improved growth or carcass yield, leading to misleading interpretations about the efficacy or nutrient sparing nature of the enzymes supplied in the diet.
Low-density single-nucleotide polymorphism (SNP) panel is a very effective way to reduce the cost of genomic selection in animal breeding. This study proposed a new type of low-density SNP panel that performed as well as an evenly spaced panel. The great performance of mixed low-density SNP panel indicates that the same strategy could be used in another field, such as genome-wide association studies.
AN19285Partition of dietary energy by sheep fed fresh ryegrass (Lolium perenne) with a wide-ranging composition and quality
Ryegrass pastures fed to sheep are sometimes green and leafy and, at other times, contain seed heads, and dead matter. Ryegrasses varying widely in quality were fed to sheep, and although they obtained much less energy from poor feeds, the amount of methane produced was similar. The amount of energy lost in urine and faeces was less than predicted by standard equations for poor-quality ryegrass, suggesting that improvements are needed for feeds typical of dry or drought conditions.
AN19152Effect of preweaning diet on performance, blood metabolites and rumen fermentation around weaning in calves of two beef breeds
Good transition from suckling to high-concentrate diets is essential to avoid nutritional disorders during the fattening period of feedlot beef calves. Preweaning supplementation with hay or concentrate improves rumen development and animal performance, and results in higher profitability when calves are sold at weaning; concentrate supplementation is the most interesting option for closed-cycle farms, whereas hay supplementation could be profitable if producers have their own crops. It is of economic interest to supplement beef calves during the suckling period.
AN18633Use of different carbohydrate sources associated with urea and implications for in vitro fermentation and rumen microbial populations
Frequent and prolonged droughts in semi-arid regions affect the availability of feed resources for animal production. Alternative feed sources have been investigated, aimed at replacing cereal grains traditionally used; however, different carbohydrate and protein sources can lead to modifications in the rumen. Based on our results, diets containing urea as a total substitute for soybean meal alter ruminal fermentation and reduce the populations of Streptococcus bovis and Ruminococcus flavefaciens in the rumen.
AN18725Inclusion of a blend of copaiba, cashew nut shell and castor oil in the protein-energy supplement for grazing beef cattle improves rumen fermentation, nutrient intake and fibre digestibility
Essential oils are secondary plant compounds with potential to replace ionophore antibiotic additives and improve nutrient utilisation efficiency. The purpose was to evaluate the effects of including different concentrations of a commercial blend of essential oils and monensin on the nutritional characteristics of beef cattle grazing pasture during the rainy season. A low concentration of essential oils (150 mg/kg DM) and monensin increased nutrient intake. A low concentration of essential oils increased fibre digestibility and nitrogen utilisation efficiency.
AN18488Modelling of breech strike risk and protective efficacy of mulesing in adult Merino sheep
Unmulesed sheep have a 6-fold higher risk of breech strike than mulesed sheep. Reductions in breech wrinkle, breech cover and dag scores can reduce this risk. This paper describes a model to indicate the level of risk for sheep of specified breech scores.
AN18657Different combinations of sodium monensin and virginiamycin during feedlot finishing of Nellore cattle
Nutritionists often recommend combinations of sodium monensin and virginiamycin in the diet for feedlot cattle. However, the effects of this combination on feedlot performance, either on the adaptation or finishing periods to prevent metabolic disorders and economic losses, it is not well documented in the literature. Based on the results of this study, feedlot cattle nutritionists may use the best combination of feed additives during the adaptation and finishing periods to improve feedlot performance of Nellore cattle consuming high-energy diets.
AN18420Milk yield at first lactation, parity, and season of calving affect the reproductive performance of water buffalo cows
Achieving a less than 400-day calving interval is the goal of water buffalo production systems. Primiparous water buffaloes, those with high milk yield, and those calving in December–July, are less likely to achieve that goal. High milk yield at first lactation leads to longer calving intervals, which highlights the importance of adequate nutrition to help high milk yield water buffalo cows to maintain a good reproductive performance.
Meat production can be increased significantly if cattle are reared within a facility with special treatment. The poor meat production characteristic of African beef industry was addressed and results showed alleviation of the problem when bulls were fed a special diet and given a safe agent that promotes growth. In addition to providing more meat for the increasing human population, this measure could be a partial solution to frequent bloody clashes between herders and farmers, especially in Nigeria.
AN18743Sweet potato (Ipomoea batatas) vine silage: a cost-effective supplement for milk production in smallholder dairy-farming systems of East Africa?
Sweet potato vines can be ensiled using smallholder scale-appropriate technology to produce high protein feed for the ruminants. Dairy cows fed sweet potato vine silage plus wheat bran had milk production similar to that of cows fed commercial grain concentrate. Marginal rates of return over feed costs were higher for animals fed the silage than for those fed grain.
AN18743 Abstract | AN18743 Full Text | AN18743PDF (182 KB) | AN18743Supplementary Material (2.5 MB) Open Access Article
AN19305Fatty acid profile, antioxidative status and dietary value of the breast muscle of broiler chickens receiving glycine-Zn chelates
Zinc is added to poultry feed as a growth stimulant. The present study aimed to examine the effect of glycine-Zn chelates on the fatty acids profile, antioxidative status and dietetic value of poultry meat. Due to the enhanced accumulation of Zn in muscles, there was a positive effect of the chelate on the oxidative stability of the meat and on the atherogenic and thrombogenic indices.
AN19160The effects of rapeseed cake intake during the finishing period on the fatty-acid composition of the longissimus muscle of Limousin steers and changes in meat colour and lipid oxidation during storage
The use of cold-pressed rapeseed cake, a by-product of small-scale biodiesel manufacturing, as a substitute for prilled palm fat in the diet of beef steers can improve the nutritional value of intramuscular fat by reducing its atherogenic index and increasing its content in healthy unsaturated fatty acids, such as oleic acid, vaccenic acid and rumenic acid. Changes in muscle fatty acid composition can occur without compromising animal growth, carcass characteristics and oxidative stability of meat.
AN19310Broad near-infrared spectroscopy calibrations can predict the nutritional value of >100 forage species within the Australian feedbase
Near-infrared spectroscopy is used to predict the nutritional characteristics of the plants eaten by herbivores. We aimed to develop taxonomically broad calibrations that allow accurate predictions for the majority of forage species grown in Australia. We found that broad calibrations can be as accurate as those developed for single-species or groups of similar species. This makes it simpler for feed testing laboratories to predict the nutritional value of novel or unidentified species and mixed swards.
AN19310 Abstract | AN19310 Full Text | AN19310PDF (375 KB) Open Access Article