Authors : Mehran Aboozar, Hamid Amanlou , Ali Mirza Aghazadeh , Kambiz Nazer Adl , Moosa Moeini and Teimour Tanha
Abstract: Metabolizable Protein (MP) supply and amino acid balance were manipulated through selection of highly digestible Rumen-Undegradable Protein (RUP) sources. Effects on production efficiency and reproduction of early post-partum dairy cows determined. Forty wo multiparous and 16 primiparous Holstein cows were assigned to diets in a completely randomized block design immediately after parturition with 3 weeks experimental periods and then were fed one ration for 120 days in milk. Diets were formulated to provide 3 concentrations of dietary RUP [LRUP 6.65, MRUP 7.72 and HRUP 8.79% of Dry Matter (DM)] which rumen-degraded protein remained constant (11.3% of DM). Diets contained 26.30% alfalfa hay, 12.60% corn silage, 9.50% sugar beet pulp and 51.5% concentrate (DM basis). Ingredients within diets were equal across treatments except for fish meal and corn gluten meal that partially replaced with steam rolled barley and soybean meal. Dry matter intake was linearly increased by treatment. Milk yield, FCM and protein content and yield all increased significantly when cows were fed diets with greater RUP but milk fat and lactose did not have different between treatments. BW changes was improved with intake of high RUP but BCS changes had significant difference and improved by increasing RUP in the diet. Number of breeding per cow, open days and first breeding conception rates had significantly increased with concuming HRUP diet (p<0.05). Also, plasma progesterone increased significantly (p<0.05) between days 11 and 21 after parturition. Plasma urea N concentrations were not statistically affected by diet. Plasma cholesterol concentrations increased significantly (p<0.05) by treatments.
Mehran Aboozar, Hamid Amanlou , Ali Mirza Aghazadeh , Kambiz Nazer Adl , Moosa Moeini and Teimour Tanha , 2012. Impacts of Different Levels of RUP on Performance and Reproduction of Holstein Fresh Cows. Journal of Animal and Veterinary Advances, 11: 1338-1345.