The Research Column

Reviewing the assumptions of genetic progress since the introduction of genomics is crucial for advising breed associations and non-academic stakeholders on how to use this technology moving forward. Therefore, the main purpose of this study was to investigate genetic trends in the five breeds receiving genomic evaluations for production, fertility, longevity, and health traits. A further objective was to investigate changes in generation intervals and inbreeding levels of these breeds.

Six treatments were compared, with two grazing intensities and three ways of supplementation, investigated at both grazing intensities. The two grazing intensities were severe and light grazing: (1) herbage allowance of 15 (severe) or 30 (light) kg DM per cow per day at 3 cm above ground level or, (2) post-grazing sward height, depending on the supplementation strategy.

The link between the rumen, the rumen microbial population, and production efficiency is well established. Recent developments sug­gest that the species composition of the rumen is predictive of dairy cow productivity and the interactions among micro-or­ganisms may play a more significant role than previously considered. Therefore, the ability to alter the rumen microbial population in a precise manner and skew the community towards a state that enables higher feed digestibility and improved animal production is a desir­able strategy to improve productivity in dairy farming.

Genetic selection for increased milk yield has been a key driver of dairy intensification and the development of highly specialized milk production systems, with increasing herd size, and heavily relying on cereals and protein-sources. Locally, the concentration of intensive dairy farms can have a large environmental impact due to the large amounts of waste produced.

The experiment was conducted in two ways: (1) by means of a nationally representative survey of US adults, and (2) by means of a randomized experimental auction with real money and real milk.

Maintaining good animal health is important for farm busi­nesses; and livestock disease outbreaks can have considerable economic consequences affecting trade, food prices, and pub­lic health. Government control efforts, such as government-mandated testing, herd move­ment restrictions, and culling of reactor animals to eliminate diseases, are often a last resort. Thus, implementing farm-specific biosecurity plans can help to mitigate disease spread in the first place, and as such avoid ‘last resort’ measures.

The process followed evaluated beta-lactoglobulin production in bioreactor cultivation with the filamentous fungus Trichoderma reesei and the downstream processing thereof for product purification. The model considered four production scenarios in four different locations (New Zealand, Germany, US, and Australia) in a cradle-to-gate system. The scenarios considered different sources of carbon (glucose and sucrose), different options for the fungal biomass treatment (waste or animal feed) and for the purification of the product.

Crossbreeding is a practice that may help to increase the economic profit by improving health, fertility, longevity or milk components, through the benefits of heterosis, which reduces the likelihood of inbreeding depression by increasing heterozygosity. The main contribution of crossbreeding is the increase of efficiency of the production system due to breeds having their genetic merits in different traits so obtaining benefits of heterosis.

Extending the voluntary waiting period (VWP) from calving until first insemination is one way of extending the lactation length beyond 305 days, which will result in an extended lactation length and CI. With an extended CI, the risk of diseases per year can be expected to reduce as there will be fewer calving events per year. It has been shown that cows with an extended VWP (150 days) had a lower incidence of metabolic disorders, lower veterinary costs and lower culling rates compared with cows with a short VWP (60 days).

The impact of SARA has mainly been studied by conducting SARA challenges in cows, sheep, and goats based on a combination of feed restriction and high-grain feeding. The methodologies applied in these studies varied considerably. Variations include differences in the duration and amount of grain feeding, the type of grain, the amount and duration of the feed restriction, the number of experimental cows, and the sensitivity of the cows themselves to the SARA challenges.