The Research Column

Bacterial contamination of foods may lead to reduced shelf life due to outgrowth of spoilage organisms and, in the case of pathogens, to food-borne illness upon consumption of contaminated products. To inactivate bacteria that may grow in finished products, heat treatment is often used. Pasteurisation usually is effective to inactivate vegetative cells, but bacterial spores will survive, after which they may germinate and grow in finished liquid products.

Successful reproductive performance is the basis for profitable dairy farming. Poor reproductive performance results in increased calving intervals and decreased milk production, and therefore significant economic losses to the farmer.

Digital cushion thickness (DCT) at the typical sole ulcer site beneath the distal phalanx is a strong predictor of lameness and the claw horn disruption lesions (CHDL’s) of sole ulcers and white line disease in dairy cows. These CHDL’s are the most prevalent claw diseases associated with lameness and pain. Previous studies are inconsistent as to the thickness which is optimum. Apparently thin digital cushions predispose animals to lameness and lesions later in lactation.

Accurate and timely detection of pregnancy is vital in commercial milk production enterprises. There are several methods to do so including observation of non-return to oestrus, trans-rectal palpation, trans-rectal or trans-cutaneous ultrasonography, and analysis of progesterone and pregnancy-associated glycoproteins in milk or blood. However, these methods have an associated cost, are not all efficient and some require animal handling, which might limit their practical implementation.

Microbial contamination is generally associated with the presence of microbial biofilms attached to the inner surfaces of tanks, pipes and milk processing lines.

Choline is a known essential nutrient as it is required for synthesis of essential membrane phospholipids, acts as a precursor for synthesis of acetylcholine, and in particular, has a role in lipid intermediary metabolism. Improving choline status pre-calving has the potential to reduce the risk of fatty liver and improve health and lactation.

Choline is a known essential nutrient as it is required for synthesis of essential membrane phospholipids, acts as a precursor for synthesis of acetylcholine, and in particular, has a role in lipid intermediary metabolism. In ruminants, however, almost all dietary choline is degraded by ruminal microbes and requires choline to be supplemented in a rumen-protected form. 

Zinc (Zn) is an essential trace mineral and plays an important role in DNA and RNA synthesis and replication and in cell proliferation. Zinc supplementation has been shown to increase milk yield, live weight and growth rate, and enhanced disease resistance. With reference to the latter, it has been suggested that Zn deficiency could result in increased somatic cell count (SCC) and ultimately increase mastitis in dairy cows. 

The health, well-being and reproductive status of dairy cows, apart from profitability in production, should be the most important considerations in animal breeding. Normally though, genetic evaluation focuses mostly on the genotypic background which influences economically important traits such as milk yield and composition. However, in many countries selection for enhanced milk performance has caused a decline in cow reproduction and consequently, this has led to increased interest associated with non-production traits, including reproductive efficiency, longevity and health.

The crossing of parents of unrelated strains, or breeds, often results in offspring that are more robust, with better health, growth, fertility, and production. In dairy cattle, crossbreeding has also been shown to improve functional traits such as fertility, health, calving ability, and survival. Despite the compelling evidence of the benefits of crossbreeding, the majority of dairy farmers still prefer traditional pure breeding, and crossbreeding in dairy cattle is far from common.