Dairy cattle ration integration with rumen-protected thiamin. Effects on milk production and reproductive efficiency
1999
Bonomi, A. | Bonomi, B.M. | Quarantelli, A. | Superchi, P. | Sabbioni, A. (Parma Univ. (Italy). Istituto di Zootecnica, Alimentazione e Nutrizione)
The AA have integrated the rations of dairy cows, during the first 6 months of lactation, with thiamin, protected by microencapsulation with fatty acid fllm or not protected, at the doses of 40 mg, 70 mg and 100 mg of active substance/head/day. Rumen protected thiamin, regardless to the dose, and not protected thiamin at the dose of 100 mg have improved the health status of the herd (reduction by 50-60% of most frequent diseases), fecundity (respectively 1.60, 1.70, 1.40, 1.90 services per conception vs. 2.10, 2.40, 2.30; 2.30 of controls), milk production (respectively 8.00%, 8.50%, 13.00%, 7.00%), milk fat (respectively 5.50%, 5.00%, 7.00%, 4.00%) and milk protein content (respectively 4.00%, 5.00%, 7.50%, 3.50%); no effect was shown on cheese making characteristics of milk. At the same doses, protected or not protected thiamin have caused changes in some blood parameters, with a rise of glucose, methionine, leucine, isoleucine, threonine and glutamic acid and a drop of acetate, phenylalanine, glycine and histidine. Not protected thiamin at lower doses (40 mg and 70 mg) was ineffective. On the basis of the results, the AA conclude that thiamin daily requirement of high producing dairy cows can be met with rumen protected vitamin at the dose of 40 mg/head/day
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