The Research Column

The nutritional and pharmacological advantages of chromium (Cr) for animals and humans have been well established. Trivalent Cr is a component of chromodulin which is involved with insulin regulation, and thereby associated with the metabolism of carbohydrates, protein and lipids. The signs of Cr deficiency include impaired nutrient metabolism, lower sensitivity of the peripheral tissues to insulin, compromised immunity and decreased weight gain and health status, specifically under stressful conditions.

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. 

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.

In some countries lameness has been identified as the third most important health-related economic loss, after fertility and mastitis. Lameness has serious negative consequences on animal welfare and the environment. Secondly, lameness may reduce the overall lifetime performance of dairy cows due to milk production loss and culling, as well as having the potential to further affect sustainability by increasing the total greenhouse gas emissions per unit of milk produced. Furthermore, lame cows are more at risk for developing future mobility issues.

Time of dry-off, calving and the start of a new lactation are critical transition events for a dairy cow. Large changes in both physiology and management increase the risk for disease and culling. The cow faces these transition events every year, as a one-year calving interval is usually aimed for. A one-year calving interval is usually associated with a good average 305-day yield and better economic results compared with longer calving intervals.

Compared with Holstein milk, some conventional milk replacer (MR) formulations provide high amounts of lactose, low concentrations of fat, and comparable crude protein levels. Consequently, MR provides a lower dietary energy density than whole milk. Fat inclusion in MR compositions should raise the energy content, but the literature shows both positive and negative results.

The environmental impact of producing animal source foods is a critical topic of policy discussion in domestic and international governments, social media, the popular press, and the consumer marketplace. Livestock’s contribution to the environmental impacts associated with food production are significant concerns for all food chain stakeholders, including livestock producers who play a major role in reducing environmental impacts per unit of food.

Colostrum management to provide adequate immunological protection to new born calves has been well investigated, and thresholds for colostrum quality, as well as optimum volume and timing for colostrum feeding have been established. However, less is known about the effect of colostrum from a single dam versus pooled colostrum from several cows on passive immunity, as well as the subsequent antibody survival in the calf.

Milk consumption is motivated by both familiarity and habit and usually decreases with age. However, consumption during childhood and adolescence increases the chances of lifetime milk consumption. Understanding how parents perceive dairy milk and other dairy foods further enables development of dairy-positive messaging that aligns with their perceptions. The objective of the research by Dr A.N. Schiano and colleagues, done in North-Carolina, therefore was to understand parent belief systems around fluid dairy milk and plant-based alternatives (PBA).

Discipline: carbon footprint; Keywords: methane, nitrous oxide, volatile organic compounds, ammonia, LCA, emissions per unit of production.

This question was discussed in an Invited Review by S.E. Place and F.M. Mitloehner of the University of California in the US, in a paper entitled: Contemporary environmental issues: A review of the dairy industry’s role in climate change and air quality and the potential of mitigation through improved production efficiency, published in the Journal of Dairy Science, Volume 93 of 2010, pages 3407 to 3416.