Effects Of Dietary Energy Level On Reproductive Hormone, Lactational Performance And Lamb Birth Growth State Of Inner Mongolia White Cashmere Goats

Via controlling the level of diet metabolic energy, this study research the effects of nutrient level on nutrients digestibility and reproductive hormone(Estradiol, Progesterone, Prolactin) during later pregnancy, lamb and colostrums of Inner Mongolia white cashmere goats. Based on body weight and condition,18 similar age goats were divided into 3 groups with no significant different. There were one control group and two trial groups. According to NRC, diet metabolic energy level of control group is 11 Mj/kg, and 2 trial groups were respectively 7.7 Mj/kg and 14.3 Mj/kg, crude protein of the groups were 125 g/d. The 3-month trial period consisted of later pregnancy and 1 month after delivery. This paper included three parts:Experiment 1 was aimed at researching ewes’ digestibility of nutrients in different metabolic energy level diets during the later pregnancy by means of collection full excrements analysis method, calculating ewes’ body weight gain. The results showed that, in the trial condition, ewes in the trial group 1 had the largest body weight gain. Meanwhile, higher diet metabolic energy could promote ewes’ apparent digestibility of nutrients, especially crude protein.Experiment 2 was designed in later pregnancy to research the effects of different diet metabolic energy levels on ewes’ reproductive hormone. The content of estradiol, progesterone and prolactin in the blood were measured. The results showed that, in the trial condition, when the metabolic energy level of diet is 14.3 Mj/kg ewes’ secretion of estradiol was increased. And the level of 14.3 Mj/kg diet metabolic energy can sustain a higher progesterone level to ensure normal pregnancy. At the same time, it is beneficial to accumulate prolactin, thus, it can ensure fetus’ growth and development. In the scope of the article, when metabolic energy levels of diet are 14.3 Mj/kg and 7.7 Mj/kg, content of ewes’ blood estradiol and progesterone show stronger negative correlation, which conforms to ewes’ physiological characteristic in pregnancy. However,7.7 Mj/kg may not sustain normal content of progesterone in pregnancy.Experiment 3 was designed in later pregnancy to research the effects of different diet metabolic energy levels on growth performance of lambs. The birth weight, body height, body length, chest circumference and cannon circumference of lambs were measured. The results showed that,7.7 Mj/kg metabolic energy limit fetus’ growth and development, so that lead to birth weight decrease. Birth weight of lamb changes with diet metabolic energy levels, and metabolic energy level significantly affect lamb’s birth weight. High level of metabolic energy diet availably increase body size of lamb.Experiment 4 was designed in later pregnancy to research the effects of different diet metabolic energy levels on lactation. Record milk production of 1 month after delivery by subtraction. The results showed that, in the later pregnancy and after delivery,14.3 Mj/kg metabolic energy significantly increase milk production in 1 month, butterfat rate and protein of foremilk, which does good to lambs’ growth and development.The consequence of the trial condition is that, during later pregnancy of Inner Mongolia white cashmere goats,14.3 Mj/kg metabolic energy of diet is beneficial for ewes’physiological state stability, ensuring fetus’ growth and development, increasing milk production and improving constitute of foremilk that makes lambs get better growth condition and improves ewes’ reproductive performance.