The Research Column

Because of concerns regarding increasing antimicrobial resistance and the need for responsible use of antibiotics, there is a need to investigate the feasibility of selective dry cow therapy and non-antimicrobial alternatives. The most common alternative to antibiotics at the time of dry-off is internal teat sealants that contain bismuth sub-nitrate, a heavy metal compound, in a paraffin-based substance. They have proven to be effective at preventing new dry-period infections.

Feed efficiency is usually expressed as the amount of milk produced per unit of feed intake. However, this definition is a ratio trait, which is challenging to incorporate in selection indices. Residual feed intake (RFI) is an alternative expression of feed efficiency. It is defined as the difference between observed and predicted dry matter intake (DMI).

As carbon dioxide, methane is a potent greenhouse gas (GHG), but when it comes to ruminant livestock and climate change there are many other characteristics which need to be considered. The important ones are: (1) it stays in the atmosphere only for about 12 years versus 1000+ years for carbon dioxide; (2) it is derived from atmospheric carbon such as carbon dioxide; (3) it is part of the biogenic (photosynthetic) cycle, and (4) it eventually returns to the atmosphere as carbon dioxide, which means it is recycled carbon.

The consumption of Mozzarella cheese in the form of Pizza toppings, salads, cheese blends have increased in recent years. The functional properties of the cheese are the ability to shred easily, melt rapidly, and reflect acceptable stretching, oiling-off and browning upon baking. Sodium chloride salt, starter cultures and acids are key ingredients in the manufacture of Mozzarella cheese and affect its functionality. Salting occurs either by brining or with dry salting.

Successful management of an automatic milking system (AMS) requires effective functioning of the milking unit (MU). It is well established that an increased detachment level, i.e. earlier removal of the teat cups at the end of milking, can decrease milking time substantially with minimal to no milk yield loss. However, these studies were all conducted at cluster level, and some studies suggest an increase in residual milk or strip yield at increased cluster detachment levels, which indicates decreased udder emptying.

Significant changes have occurred in the US dairy industry in the last decade, involving the number of dairy farms, herd size, milk quality, and management practices. Although the number of dairy cows in the United States has remained relatively constant over the past decade, at approximately 9 million head, the number of dairy operations has decreased by 30%, resulting in larger dairy farms. This trend is even more prevalent in the south-eastern United States, where the number of dairy farms has decreased by 39% from 5315 in 2008 to only 3235 in 2017.

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.