Several cows eating hay in a dairy farm

Evaluation of supplemental carnitine in dairy cows during the pre- and postpartum period

Alvaro Garcia

The transition period is the most challenging time for a dairy cow. Right after calving cows start producing colostrum first and then milk in large amounts, depending on their genetic make-up. At this point in time however, they are in recovery mode from calving, and a combination of general discomfort/pain and hormonal changes results in a significant reduction of feed intake.

This mismatch between nutrient requirements for production and nutrient uptake through feed intake, results in imbalances, with the supply of energy being the more striking. One example of hormonal changes is the decreased production of insulin that leads to decreased glucose utilization by insulin-sensitive organs, which is essential for milk production. Concomitantly, body fat reserves are mobilized to supply additional energy which increases the non-esterified fatty acids (NEFAs) blood concentration.

The abundance of circulating NEFAs leads to increased availability of the product from their degradation, acetyl-CoA, which may exceed the capacity of its incorporation into the carboxylic acid cycle. As a result, end-products normally utilized in ketogenesis will build-up, such as acetone, acetoacetic acid, and beta-hydroxybutyric acid (BHBA).

L-carnitine helps to handle excessive non-esterified fatty acids

The increased circulation of NEFAs leads to triacyl glyceride synthesis later deposited in the liver. To handle the excessive NEFA availability L-carnitine is needed which is essential to transfer fatty acids into the mitochondria for their oxidation. L-carnitine is synthesized endogenously, and it is essential in the initial steps of the ß-oxidation of free fatty acids. When in short supply, all the events described above can happen leading to frequent metabolic problems in transition cows such as fatty liver and/or ketosis.

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Brown sugar and white sugar

Feeding protected glucose to transition dairy cows

Ishaya U. Gadzama & Fernando Diaz

Dairy cows require glucose during lactation for milk synthesis and maintenance of body tissues. Ruminal degradation of soluble sugars and starches into volatile fatty acids limits the amount of glucose that can be absorbed in the small intestine. This may limit milk synthesis and reproductive performance during the lactation.

Post-ruminal supply of glucose has been proposed as a dietary strategy to improve cow’s productive performance and health status. A study conducted at the Experimental Dairy Farm of the Hunan Institute of Animal and Veterinary Science, Changsha, China investigated the effects of feeding rumen-protected glucose (RPG) on the performance of transition cows.

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Made from milk fat: butter and cream

Effects of feeding emulsifiers on milk fat yield

Fernando Diaz

Emulsifiers are amphiphilic substances capable of mixing lipids and water. In nonruminant animals, feeding emulsifiers has been shown to increase growth, feed efficiency, and nutrient absorption. In ruminants, emulsifiers have the potential to affect rumen fermentation making fatty acids more available for biohydrogenation and increasing their passage to the small intestine through association with the liquid phase. Research studies on using emulsifying agents as feed additives for dairy cows is very scarce.

A recent study conducted at the Ohio Agricultural Research and Development Dairy Center, The Ohio State University, evaluated the potential use of an emulsifier as a feed additive on ruminal fermentation and production performance in lactating dairy cows.

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