The Research Column

Waste milk (WM) may be colostrum and milk derived from cows undergoing treatment for several ailments, including clinical mastitis, foot and reproductive diseases etc. Additionally, WM may have elevated SCC, rendering it unsuitable for commercial use.

Dry matter intake (DMI) plays a major role in characterizing feed efficiency in dairy cattle and has been widely used in dairy nutrition research. As feed represents the largest operating cost in dairy production, feed efficiency has gained increased attention for genetic selection.

To limit methane emissions, many recent feeding strategies have been directed towards the potential of inhibiting ruminal methanogenesis. Some of the most promising include supplementation of fat and addition of feed additives/rumen modifiers such as nitrate and 3-nitrooxypropanol (3-NOP).

Determining the optimal insemination time for individual cows is not always easy, as amongst others, pregnancy also has an effect on absolute milk yield; the latter which has been reported in several studies. There is however, limited quantitative information between the association between days-post-conception (DPC) and lactation persistency, based on a lactation curve model, and, specifically, how persistency changes during pregnancy and relates to the days in milk at conception (DIMc).

Some consumers prefer pasture-derived dairy products, as they perceive outdoor pasture-based feeding systems as a more natural environment for animals. Despite this, the number of grazing animals globally has declined as a result of the higher milk yields achieved by indoor TMR feeding systems, in addition to the changing climatic conditions to control the milking environment.

In the majority of calf rearing systems, dairy calves are raised in individual hutches for biocontainment purposes and to facilitate monitoring and handling of calves. However, individual hutches restrict calves’ activity and social interactions. Some studies showed that group housing (GH) may be beneficial to calf welfare and is associated with social benefits. However, the adoption of GH on dairies is hindered by several concerns, with the primary concern being the potential for increased transmission of diseases due to heightened calf-to-calf contact.

The profitability of seasonal, pasture-based dairy systems is substantially reduced by poor reproductive performance. Dairy producers desire a timely and condensed calving pattern as a strategy to align the feed demands of the herd to the seasonal feed supply from pasture grazed. Holstein-Friesian and Jersey cattle have gestation lengths around 280 days; therefore, to maintain an annual calving pattern, each cow must resume normal oestrous cycles and initiate a pregnancy within 85 days after calving.

The dairy cow experiences impaired health, productivity, fertility, and overall welfare when outside her thermo-neutral zone. The thermo-neutral zone is defined as the range of temperatures within which no additional energy is spent to heat or cool the body and typically falls between 5°C and 25°C for dairy cows.

Persistency of lactation measures the ability of a cow to maintain daily production following peak production. A cow with more persistency of production usually have a more horizontal lactation curve compared with a cow with less persistency of production.

The importance of obtaining greenhouse gas (GHG) and corresponding resource use data on dairy farms cannot be emphasised enough, as baseline data is required to evaluate where to put emphasis in mitigation or change. The publication from South-Western Sweden cited provides such an opportunity. The authors collected data and use Life Cycle Assessment (LCA) methodology in analysis.