Comparison of daily gain, rumen fermentation, and blood parameters of fattening yaks under grazing and house feeding patterns

The objective of this study was to investigate the effects of grazing and house feeding patterns on the daily gain, rumen fermentation, and blood parameters of fattening yaks. This would be useful in providing a theoretical basis for the transformation and upgrading of yak feeding management and fattening pattern selection in production practices on the Qinghai-Tibetan Plateau. For this, 12 4-year-old castrated male yaks in a healthy condition with similar body weights (202 ± 5.2 kg) were randomly divided into two groups: Natural grazing (NG) and house feeding (HF). Yaks in the NG group were fattened using the traditional grassland grazing pattern, while yaks in the HF group were fattened through the modern short-term house feeding pattern. The results subsequently showed: 1) The average daily gain of yaks was greater in the HF group than the NG group (P < 0.05), which was increased by 36% more than the NG group. 2) The concentrations of total volatile fatty acids, acetate, propionate, butyrate, and acetate/propionate in the rumen fluid of yaks were all reduced (P < 0.05). 3) The number of red blood cells, hemoglobin, hematocrit, erythrocyte volume distribution width, and platelet counts in yak serum were all higher in the NG group than in the HF group (P < 0.05), whereas white blood cells and mean hemoglobin were significantly lower in the HF group (P < 0.05). Additionally, the other blood physiological and biochemical indexes were unaffected by the fattening pattern (P > 0.05). 4) The serum activity of glutathione peroxidase was significantly higher in the NG group than the HF group (P < 0.01), whereas no significant differences in the other antioxidant indexes between the two treatment groups (P > 0.05). In conclusion, compared to traditional grazing patterns, short-term fattening improved the rumen fermentation profile of yaks, increased the average daily gain, and had higher productivity and fattening efficiency. However, grazing yaks also had a higher capacity in terms of oxygen carrying and antioxidants, while exhibiting an enhanced ability to cope with the harsh highland environment.