Comparison Study of Growth Performance,Nutrient Digestion,Rumen Fermentation and Blood Physiological Indexes between Yaks (Bos grunniens) and Cattle (Bos taurus) under Low-Concentrate Barn Fattening北大核心CSCD

This study was aimed to compare the growth performance, nutrient digestion, rumen fermentation and blood physiological indexes between yaks (Bos grunniens) and cattle (Bos taurus) under low-concentrate barn fattening, which provide data reference and technical support for breed and feeding technology selection of fattening beef cattle in the Qinghai-Tibetan Plateau. In this experiment, six healthy yaks (211 ±6) kg] and six healthy Qaidam cattle (210±7) kg], all castrated and 4 years of age, were selected and raised in individual metabolic cages. The experimental diets consisted of concentrate (2.0 kg / d per head) and forage (ad libitum) . The pre-experiment lasted for 10 days, and the trial lasted for 95 days. The results showed as follows: 1) total dry matter intake were significantly lower in yaks than cattle (P<0.05), whereas average daily gain was not different between yaks and cattle (P>0.05), therefore, feed / gain was significantly lower in yaks than cattle (P<0.05) . 2) There was no difference between yaks and cattle in apparent digestibilities of nutrients (P>0.05) . 3) Ruminal pH tended to be higher (P = 0.083), and the concentrations of iso-volatile fatty acids (VFAs) were significantly greater in yaks than cattle (P<0.05), whereas the concentrations of total volatile fatty acids (TVFA), acetate, propionate and butyrate were not significantly different between yaks and cattle (P>0.05) . 4) Concentrations of ammonia nitrogen, free amino acid nitrogen and soluble protein nitrogen in rumen were significantly greater in yaks than cattle (P<0.05) . 5) The red blood cells (RBC) amount, hemoglobin (HGB) content, hematocrit (HCT) and red blood cell volume distribution width (RDW-CV) were significantly lower (P < 0. 05), whereas mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) content and platelets (PLT) amount were significantly higher in yaks than cattle (P<0.05) . In conclusion, yaks have lower feed intake, but have a greater feed conversion efficiency than cattle, therefore, yaks can produce a greater economic benefits than cattle under low-concentrate barn fattening system. © 2023 Authors. All rights reserved.