Study On Protein And Energy Requirements Of Northwest Tibetan White Cashmere Goat In Late Gestation Period

Tibetan Northwest white cashmere goats have a long history of rearing and are resistant to rough feeding and rebellion.Cashmere is a popular raw material for the textile industry because of its high quality,and cashmere products are very popular with consumers.However,at present,the Tibetan Northwest white cashmere goats are mainly grazed,with rough feeding management and lack of guidance on feeding standards.Tibetan Northwest white cashmere goats had unique habits and nutritional needs,and existing standards for velvet goats breeding do not apply.In this study,the protein and energy nutritional requirements of Tibetan Northwest white cashmere goat ewes at 90 days of pregnancy were investigated in two independent experiments using a single-factor randomised experiment design,a feeding experiment,a digestion and metabolism experiment and a slaughter experiment,with a view to providing basic data for the formulation of feeding standards for Tibetan Northwest white cashmere goats.The main results obtained in this study are as follows:1.In this experiment,20 ewes in good condition and of similar weight at 90 days of pregnancy were selected as the test sheep.The test was designed using a single factor randomised trial approach,and the 20 test ewes were randomly divided into four groups,each with five replicates,one test ewe per replicate,and kept in a single pen.Before the feeding test,one ewe from each group was selected for slaughter,and the rest of the test ewes were subjected for growth test.The four test diets were designed to have a digestible energy level of 10.50 MJ/kg and protein levels of 7.79%（Ⅰgroup）,9.50%（Ⅱgroup）,10.93%（Ⅲgroup）and 12.35%（Ⅳgroup）respectively.Digestion and metabolism tests were carried out in the middle of the feeding trial,using whole faecal and urine collection methods.The following results were obtained after analyse and measurement:Dietary protein level had no significant effect on the apparent crude protein digestibility of the test ewes.The average daily weight gain of the ewes in the four experimental groups increased significantly with increasing dietary protein levels.There was no significant effect of diet protein level on pregnancy product and lamb newborn weight,and pregnancy products and first birth weight increased and then decreased in the four test groups as dietary protein levels increased.Combining the above data,the regression formula of metabolic weight and average daily gain with nutrient requirement of crude protein and digestible protein of Tibetan Northwest white cashmere goats in late pregnancy phase were:CP（g/d）=6.5152W^0.75+0.7830 ADG（P<0.05 R²=0.9662）DCP（g/d）=4.0760 W^0.75+0.7404 ADG（P<0.05 R²=0.9623）2.In this experiment,20 ewes in good condition and of similar weight at 90 days of pregnancy were selected as the test sheep.The test was designed using a single factor randomised trial approach,and the 20 test ewes were randomly divided into four groups,each with five replicates,one test ewe per replicate,and kept in a single pen.Before the feeding test,one ewe from each group was selected for slaughter,and the rest of the test ewes were subjected for growth test.The four test diets were designed to have a protein level of 10.8%and digestible energy levels of 8.5 MJ/kg（Ⅰgroup）,10.0 MJ/kg（Ⅱgroup）,11.5MJ/kg（Ⅲgroup）and 13 MJ/kg（Ⅳgroup）respectively.Digestion and metabolism tests were carried out in the middle of the feeding trial,using whole faecal and urine collection methods.The following results were obtained after analyse and measurement:The energy intake,energy metabolic rate and digestive energy metabolic rate of ewes in the four experimental groups showed a significant increase with increasing energy levels.The average daily weight gain of the ewes in the four experimental groups increased significantly with the increase in the energy level of the diets,and the digestible energy level of 8.47 MJ/d could not meet the energy requirements of the ewes of Tibetan Northwest white cashmere goats in late pregnancy phase.Dietary energy levels had no significant effect on pregnancy products and lamb newborn weight.Combining the above data,the regression formula of metabolic weight and average daily gain with nutrient requirement of digestive energy and metabolic energy of Tibetan Northwest white cashmere goats in late pregnancy phase were:DE（MJ/d）=0.6988 W^0.75+0.0762 ADG（P<0.05 R²=0.9977）ME（MJ/d）=0.3646 W^0.75+0.0741 ADG（P<0.05 R²=0.9975）In summary,the study established regression formulas for protein and energy requirements of Tibetan Northwest white cashmere goats in late pregnancy using a combination of daily weight gain,nutrient digestibility,initial lamb weight and nutrient deposition to provide an important reference basis for scientific and accurate feeding of Tibetan Northwest white cashmere goats.