Use of trace-mineral boluses on dairy heifers

Andrés Haro & Fernando Diaz

Among the nutrients required by ruminant animals are trace-minerals such as: iodine (I), cobalt (Co), copper (Cu) and selenium (Se). These minerals are required for several vital functions of the organism, fundamental to optimize dairy cow performance. When deficient they can induce pathologies such as metabolic problems. The uses of boluses for a slow release of some of these minerals in the rumen has recently received greater attention by dairy farmers.

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Types of corn silage and trace minerals affect dairy production

Alvaro Garcia

Forages and their fiber have a large effect on milk production, since they constitute the largest nutrient fraction in dairy cow diets. Their chemical composition together with their physical characteristics help maintain a healthy rumen environment critical to animal health and productivity. Corn silage constitutes the main forage used in dairy cow diets in several parts of the world.

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Calf portrait

Zinc chelates improved diarrhea and intake in young calves

Alvaro Garcia

Diarrhea or scours is the first leading cause of death in un-weaned heifer calves. It occurs most frequently between days 3 and 30 after birth, depending on the susceptibility of the individual animal and the cause of this multifactorial problem. According to the 2011 National Animal Health Monitoring System survey, diarrhea and digestive problems affect 25.3% of pre-weaned heifers and of these, 18.2% are treated. In addition, death rate in pre-weaned heifers is 7.8% with diarrhea accounting for 56.5% of this mortality.

Diarrhea is affected by pathogen exposure, calf management, environmental conditions, nutritional and immune status. Adequate amount and timely intake of colostrum is critical for calves to survive it. Once the intestinal epithelium is “closed” (first 1-2 days) to the initial absorption of large molecules, it then acts as a barrier to pathogens. The intestinal integrity of this epithelium is then critical to protect the young calf from bacterial challenges. It has been suggested that Zn is essential for normal function of this intestinal barrier, and the regeneration of its damaged epithelium.

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Importance of selenium source under heat stress conditions

Importance of selenium source under heat stress conditions

Fernando Díaz

Selenium is an essential trace mineral that is an indispensable component of the antioxidant system. Selenium is an essential element of antioxidant enzymes such as glutathione peroxidase, and its deficiency may result in an imbalance of redox homeostasis and ultimately oxidative stress.

Since selenium content in plants is highly variable, selenium is normally supplemented in dairy cow diets using inorganic sources (sodium selenite, sodium selenate), organic sources (selenium yeast, hydroxy-selenomethionine) or a combination of both. Ruminal metabolism and intestinal absorption of these selenium compounds differ as well as their antioxidant capacity.

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