The Research Column

Water use on the dairy farm is important to know how much should be provided for the animals, for cleaning purposes, for irrigation and general use. It is normally a surprisingly high figure which therefore should be well-managed. In intensively managed, confinement dairy systems water use because of relative ease of determination has been widely studied, but few reports exist regarding water use on pasture-based dairy farms. The objective of the study by Dr C.D.

Discipline: supplementation; Key words: amino acids, milk protein, meta-analysis, immune-metabolism, methionine, transition period. 

Discipline: reproduction; Key words:conception rate, dairy cow, leptin, metabolic variables, milk progesterone.

Reducing on-farm storage and retail waste should increase agricultural resource efficiency and, thus, food availability. One way of reducing waste and increase efficiency could be to reduce inclusion of human-edible products such as cereal grain (e.g. maize, wheat, oats etc) and soybean meal in the diets fed to dairy cows in intensive production systems.

Serum total Ca (tCa) and whole-blood ionized Ca (iCa) were monitored in 24 multi-lactation Holstein cows after parturition. Pre-calving diets were formulated with a positive dietary cation-anion difference of 172 mEq per kg of DM and contained 4.1 g of Ca per kg of DM. At calving, cows were blocked by calving sequence and blood Ca status as either normo-calcaemic (cut-off threshold of iCa equal or more than 1.10 mmol per L) or hypocalcaemic (cut-off threshold of iCa less than 1.10 mmol per L).

Dairy cows often experience negative energy balance in early lactation because the energy intake is insufficient to meet the sudden increase in demand for milk production. Therefore, high-starch diets are usually fed to early-lactation dairy cows to reduce the energy deficit. However, high-starch diets during the first several weeks after calving may decrease rumen pH and further increases the risk of sub-acute ruminal acidosis (SARA).

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

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.

Numerous studies have shown the negative effects of heat stress during the dry period on dairy cow performance during the subsequent lactation. Exposure of cows to heat stress during the dry period is associated with compromised mammary cell formation and decreases in milk yield in the subsequent lactation. Moreover, a greater incidence of postpartum disorders and lower reproductive performance are associated with exposure of cows to heat stress during the dry period. Dry period heat stress also decreases dry matter intake and body weight, gestation length, and calf weight.

Heat stress has been estimated to cost the dairy industry in the United States more than $900 million annually due to production losses. The main contributors to heat stress are temperature, humidity, and the temperature-humidity index (THI). A THI of 68 to 72 has been reported to induce heat stress in cows and decrease milk production. Prior research has been conducted on heat abatement measures in free stall barns with sprinklers, evaporative cooling, and fan design.