Comparative analysis of production performance of multiple Suffolk sheep under grazing conditions of two grassland types on the northern slope of Tianshan Mountains in Xinjiang.

The purpose of this experiment was to explore the monthly dynamic changes of yield and nutrient components of temperate desert-steppe type rangeland and temperate steppe-desert type rangeland on the northern slope of Tianshan Mountains in Xinjiang, and the effects of grazing on the weight changes of multiple Suffolk ewes and weaned lambs under the conditions of two grassland types. Suffolk postpartum ewes with a similar weight of two years old and 120 lambs after weaning were randomly divided into two groups. Each group had three repetitions, and each repetition had 20 sheep. Group A lambs and Group C ewes were grazed in temperate desert-steppe type rangeland experimental area (type I grass group, namely Festucasulcata, feather grass and Seriphidium kaschgaricum), while Group B lambs and Group D ewes were grazed in temperate steppe-desert type rangeland experimental area (type II grass group, namely Seriphidium borotalense Ling et Y. R. Ling, Kochia prostrata and Carex turkestanica). The trial period was 120 days. The results showed that in June and September, the fresh grass yield of type I grass group was significantly higher than that of type II grass group (P<0.05). In September, the hay yield of type I grass group was significantly higher than that of type II grass group (P<0.05). In June, the dry-fresh ratio of type I grass group was significantly lower than that of type II grass group (P<0.05). In June and September, the crude ash content of type I grass group was significantly lower than that of type II grass group ( P<0.05). In July, the crude protein content of type I grass group was significantly higher than that of type II grass group (P<0.05), and in September, the crude protein content of type I grass group was significantly lower than that of type II grass group (P<0.05). The content of nitrogen-free extracts of type I grass group in June was significantly higher than that in September (P<0.05). In June, July and September, the phosphorus content of type II grass group was significantly higher than that of type I grass group (P<0.05). There was no significant difference in total weight gain, average daily weight gain, and relative weight gain between the two grazing grassland types (P>0.05). The weaned lamb weight increased continuously, and the litter size, litter weight, and weaned weight of ewes in the following year had no significant difference (P>0.05). The results showed that with the increase of temperature and the decrease of precipitation, the forage yield of the two grazing grassland types decreased first and then increased, and the forage nutrition level decreased. The grazing adaptability and stress resistance of multiple Suffolk sheep were better under extreme environmental conditions. [ABSTRACT FROM AUTHOR]