Document Type : Research Paper
Authors
1 Ph.D candidate in Animal Nutrition, Urmia University, Urmia, West Azerbaijan, Iran.
2 PhD, Full Professor in Animal Nutrition, Department of Animal Science, Faculty of Agriculture, University of Tehran, Karaj, Alborz, Iran
3 PhD, Associate professor in Animal Nutrition, Department of Animal Science, Faculty of Agriculture, Uremia University, Urmia, West Azerbaijan, Iran.
Abstract
The aim of this study was to compare the effect of feeding different fat supplements on the production performance and some parameters of blood and rumen in fresh Holstein cows. Thirty two cows with an average body weight of 649.28 ± 29.11 kg and body condition score of 3.78 ± 0.30, were randomly assigned to each of the 4 experimental treatments. The duration of the experiment was from parturition to 21 days postpartum. The experimental diets were: 1) no fat supplement, 2) calcium-salt of unsaturated fatty acids, 3) calcium-salt of saturated fatty acids, and 4) mixture of both (1:1). Dry matter intake and milk production were recorded daily. Cows were weighed at d 7, 14, and 21DIM. Blood samples were taken after morningfeeding at d 0, 7, and 21 DIM. In order to measure fermentation parameters, the ruminal fluid samples were taken on the 21st day postpartum. Calcium salt of unsaturated fatty acids decreased and saturated and mixed increased dry matter intake (P<0.05). Milk yield, fat content, 4% fat corrected milk yield, energy corrected milk yield and feed efficiency, and the plasma concentrations of beta-hydroxybutyrate and ruminal fermentation parameters were not affected by the treatments. The plasma concentration of non-esterified fatty acids in the control and second treatment group were above the matgine. According to the results of the research and performance of the cows, in the diet of fresh cows, an equal mixture of fatty acid supplements containing saturated and unsaturated fatty acids can be used.
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