Dairy R&D in SA

Discipline: crossbreeding; Keywords: milk production, adaptability, Nguni, veld supplementation, suckling, temperament.

Discipline: genomic assessment; Keywords: homozygosity, pedigree-based inbreeding, dairy breeds, Dairy Genomics Program.

Small effective population sizes and inbreeding are major challenges faced by dairy cattle populations worldwide. Estimates of pedigree-based inbreeding (FPED) are unreliable due to a lack of pedigree data and pedigree errors and that may lead to an underestimation of inbreeding rates. Thus, inbreeding based on runs of homozygosity (FROH) has become the preferred method of estimating inbreeding as it is able to accurately predict the amount of autozygosity within the genome. No genomic estimates for inbreeding in SA dairy breeds are currently available, and therefore the aim of the study of the authors cited below was to estimate genomic inbreeding and effective population sizes for these breeds.

Discipline: selection; Keywords: female fertility, service records, pedigree data, genetic evaluations.

Female fertility is a fundamental trait for a profitable dairy herd enterprise. Studies have shown a decline in fertility probably because of dedicated selection for increased milk production. Age at first calving (AFC) and calving interval (CI) are prominent indicator traits to improve fertility, but these traits are greatly affected by management decisions. Service data present additional selection criteria with minimum bias. Service data are not recorded routinely into the national database but are kept on farm for management purposes, but should be useful to the selection effort. Therefore, the aim of the study by the authors cited below was to estimate genetic parameters for AI service-based heifer and cow fertility traits in Holstein herds.

Discipline: rumen fermentation; Keywords: feed additives, amino acids fluid-associated bacteria, particle-associated bacteria

Discipline: production; Keywords: smallholder, normative and deterministic model, herd profitability, gross margins.

Discipline: stress; Keywords: Economic evaluation, feed intake, heat tolerance indicators, water intake.

Discipline: feeding; Keywords: PUFA, pregnancy, culling, BCS, digestibility, microbial protein

Research in the past 50 years has shown that the general health of dairy cows can be improved by higher post-ruminal delivery and absorption of poly-unsaturated fatty acids (PUFA), especially omega-3 (n-3) acid. Since flaxseed contains a high concentration of n-3, the objective of the authors cited below was to evaluate the effects of feeding the flaxseed-based supplement LinPro on the production and health of mid-to-late lactation multi-lactation Holstein cows.

Discipline: environment; Keywords: methane mitigation, SF6, temperate pasture, urea.

There is not much information on the effect of dietary nitrate addition as a method to mitigate methane in grazing dairy cows. Therefore, the authors cited below did a study aiming to investigate the effect of nitrate addition on daily enteric methane emissions, production performance and rumen fermentation of multi-lactation Jersey cows grazing perennial ryegrass pasture, which contained about 7.3 g nitrate per kg dry matter (DM).

Discipline: stress; Keywords: antioxidant herbs, anti-oxidative status, immunity, Jersey cows, milk yield.

Discipline: competitiveness; Key words: efficiency, market access, productivity, people, planet, management, education, commercialisation, environmental stewardship.

Competitiveness is a function of efficiency, market access (broadening of the market of dairy products is a primary goal) and sustainability. In addition to volatility, structural and consumer needs of markets which with up-to-date information can be addressed only partially, sustainability is progressively also influenced by issues which can be categorized within the three P concepts: Productivity (economic focus), People (sociological focus) and Planet (environmental stewardship focus). The priorities which have been identified and will form the nucleus of activities supported by Milk SA are the following: