The present review shows the application of molecular genetics in different areas of livestock production. The aim was to give good examples to be used in teaching or research. As far as we know, it is the first review that pieces together many aspects of molecular biology in animal husbandry.

The intensive genetic selection over the past years has resulted in cows with high milk yields, but this increase has been linked to poor oestrus expression and mastitis causing financial losses. In Brazil there are no studies involving correlations between somatic cell score and production using random regression models. Favourable additive genetic correlations between somatic cell score, persistency and milk yield suggested that there has been a low indirect gain in somatic cell score and persistency.

The present study demonstrated alterations in the health of newborn piglets and low vitality scores were due to the effects of the parity of the sow. The objective was to determine the effect of sow parity on neonatal piglet health and vitality at birth. Results suggest that not only births classified as distocic affect the physiological responses of newborn piglets.

Artificial insemination is a tool to produce calves with improved performance in extensive management systems. This trial evaluated different post-timed artificial insemination (AI) managements, and shows that resynchronisation programs of 22 or 30 days are more efficient to produce AI products, and final pregnancy is similar among the treatments, differing only in the amount of calves produced by AI.

Dietary polyunsaturated fatty acids supplementation induces a reduction in the amount of pro-inflammatory mediators. We studied their influences on serum interleukin-1 receptor antagonist concentrations in horses subjected to regular training as a source of inflammatory reactions. A regular training program induces an inflammatory response 20 days after its starts; omega 3 fish oil supplementation had an influence on the inflammatory reaction starting form 30 days of supplementation.

Omega-3 and omega-6 fatty acids are considered to be nutritionally essential but cannot be synthesised by humans and animals. The balance of these two fatty acids is important for health and longevity rather than the absolute amount, therefore this study focused on evaluating the dietary supplementation of varying ratios of omega-6 : omega-3 fatty acids (15 : 1, 10 : 1 and 5 : 1) on the performance, nutrient digestibility, immune status and faecal microbiota of weaner pigs. As a result of this study, the reduction of the omega-6 : omega-3 fatty acid ratio from 15 : 1 to 5 : 1 in the diet showed a positive effect on the growth performance of pigs during phases 1 and 2; dry matter, nitrogen and energy digestibility and HDL cholesterol concentration increased linearly during week 3 but no effect on faecal microbiota were observed with the reduction of the omega-6 : omega-3 FA ratio from 15 : 1 to 5 : 1, indicating that the ratio of 5 : 1 is beneficial to weaner pigs.

Methionine is one of the materials for protein synthesis. This study investigates the effects of dietary methionine deficiency followed by replenishment on growth performance and carcass characteristics of lambs. The results show that dietary methionine deficiency in early life retarded the growth and development of lambs. However, the growth rate was not retarded during the 28 days of subsequent methionine replenishment stage.

On many pasture-based dairy farms in Mediterranean climatic zones, lactating cows also rely on conserved forage for periods as the main dietary forage source. We showed that switching gradually over 10 days from a grazed pasture to a grass silage-based diet increased milk yield significantly compared with an immediate changeover without any adaptation period. In regions where grazed pasture becomes unavailable, a gradual introduction of grass silage to cows will be more profitable for producers.

The objective of this study was to investigate the effect of three methods of oral selenium-enriched yeast supplementation (maternal, post-calving, and maternal and post-calving) on the blood characteristics and growth of Holstein dairy calves. Maternal supplementation improved the growth and health characteristics of calves at calving time. However, post-calving and pre- plus post-calving supplementation were not more effective than pre-calving supplementation alone.

Maize silage is widely used worldwide to feed dairy cows and beef cattle. In tropical conditions in particular, maize silage has low stability and its nutritive value declines when it is exposed to air after the silos are opened. The present study revealed that combining Lactobacillus plantarum with L. buchneri or Bacillus subtilis in maize silage is not effective in improving feed intake and growth performance of finishing feedlot beef cattle.

Long-term (Rusitec) and short-term (batch culture) in vitro studies were conducted to investigate the effects of adding gallic acid, a component of hydrolysable tannins, to ruminant diets on rumen fermentation and to test possible interactions between gallic acid and ethanol on fermentation. Beneficial effects of gallic acid on feed digestion and methane production were short term, whereas improvements in nitrogen metabolism were long term. The function of gallic acid was not affected by ethanol addition.

Stress is the main factor limiting the performance and immunity in intensively reared broiler chickens. The ill effects of stress can be minimised through fortifying their diet with natural herbal derivatives. Broiler diets were supplemented with moringa leaf meal and pomegranate peel meal, which reduced stress and improved immunity. Supplementation of moringa leaf meal and pomegranate peel meal improved immunity and reduced stress in broilers.

Glycerin, a co-product of biodiesel production, may also be a valuable dietary energy source for poultry. The growth of biodiesel has led to the production of glycerin in amounts that are greater than the capacity to use it. Therefore, glycerin can cause serious environmental damage if not properly used. Results showed that mixed semi-purified glycerin can be used at up to 7.5% in broiler diets without impairing performance or meat quality. Thus, glycerin can be considered a potential energy ingredient for broiler diets.

Legumes, among them pea, can be cultivated in cool-climate zones, are the main source of protein in human and farm animal nutrition. Unfortunately, legume seeds contain substances that limit their utilisation especially in young, most delicate animals; therefore, in this experiment, the possibility of using new varieties of pea in sow, piglet and growing-pig nutrition was evaluated. Results pointed to the possibility of using cheap on-site produced protein in the whole cycle of pig feeding.

Improved liveweight gain in the grasscutter requires adequate dietary protein supply, which is a function of the animal’s physiological state and feed. This experiment determined the protein requirement of growing grasscutters fed diets containing forage meal, and found 18% crude protein as the optimum. This discovery provides an opportunity for feed developers to utilise forage meal as an ingredient in grower-grasscutter diets.

Dingoes are known to prey on calves, although separating predation from other causes of calf loss has long been difficult. The present study found that where the use of poisoned meat baits, or other influences, caused dingo activity to be half that on unbaited control sites, there was no significant difference in calf survival. Because we did observe predation on calves, it is likely that either the baiting method did not reduce dingo numbers sufficiently to protect calves, or that uncontrolled cow age or cattle diseases confounded results.

The behaviour of birds can affect their performance parameters and laying hens’ behaviour can be affected by nutritional factors such as zinc. The aim of the present study was to evaluate the effect of zinc on performance and behavioral parameters of laying hens. The results showed that zinc can improve laying performance and can decrease aggressive behaviour.

Avian colibacillosis caused by avian pathogenic Escherichia coli (APEC) is responsible for heavy economic losses to commercial broiler farmers. The present work investigated APEC isolates and their comparison with avian faecal E. coli (AFEC) isolates. The results suggest that virulence genes were more prevalent in APEC than in AFEC and the majority of the APEC isolates exhibited a multi drug resistant pattern. The present study will serve as a reference study for future work on APEC and extra intestinal pathogenic E. coli.

Depending on the stage of lactation, heat stress diminishes milk production in dairy cows differently. Two lactations stages (12 and 201 days in milk) and three mitigation strategies (none, only shade and shade combined with sprinkling and ventilation) were evaluated. Animal productivity was more negatively affected in early lactation, although mitigation strategies were effective to reduced heat stress effects on both stages of lactation.

Knowledge of herbage mass per paddock is important for managing rotational grazing on pasture-based dairy farms. The aim of the present study was to model a value proposition for collecting and using this information, with a value estimated at NZ$385/ha versus a cost of collecting of NZ$20-40/ha. This result can help farmers evaluate the effort of collecting the data versus the opportunity to improve the profitability of their businesses.

Small-scale dairy systems are a development option to ameliorate rural poverty, but in Mexico they have high feeding costs due to reliance on external inputs. This work shows that ryegrass/white clover pastures under grazing may meet protein requirements of lactating dairy cows for moderate milk yields with similar feeding costs than cut-and-carry pasture but with less effort and; and full replacement of commercial concentrate by locally produced maize grain in the diet can maintain milk yield and milk composition of dairy cows grazing pasture under small-scale dairy systems in Mexico.

The data in the present study are of practical importance to effectively take advantage of local forage recourses to produce feeds for dairy cows on the Tibetan Plateau. The use of propionic acid and lactic acid bacteria inoculants together could improve the fermentation quality, aerobic stability and in vitro dry matter digestibility of total mixed ration silage. Further research is needed to explore how the total mixed ration silages affect animal performance.

Oestradiol only hormonal growth promotants (HGPs) have less impact on meat eating quality than does a combination of trenbolone acetate and oestradiol HGPs when used in steers finished in a feedlot for 73 days. The Meat Standards Australia beef-grading model currently has one adjustment for the known negative impact that HGPs have over and above ossification and fat measurements, which does not differentiate between HGP types. HGPs increase muscle deposition in a live animal and decrease eating quality postmortem partly through an increase in calpastatin.

The results of the present study will provide information on the objective comparison of the quality depending on different age of young Holstein bulls. Further research should be conducted to find a better Holstein veal quality in the aspects of functional, sensory, economic and health benefits. The advantages of savings in feed cost should be considered for Holstein farmers, by advancing existing slaughtering age from 20 months to less than 8 months of age. Therefore, the production of Holstein calf beef could contribute to discrimination of Holstein beef from Hanwoo and imported beef in the domestic beef market.