| This paper mainly studied on partitioning of nitrogenous compounds and cashmere growth in Inner Mongolia White Cashmere (IMWC) goats treated by different length of photoperiod and implanted melatonin in Telogen(from February 20 to June 20) and Anagen(from August 10 to December 30), respectively. 18 mature goats, 23~25kg , were fed in pens in three groups of 6 goats, which were treated with Long Daily Photoperiod (LDPP, 16L: 8D), Short Daily Photoperiod (SDPP, 8L:16D) and Natural Daily Photoperiod (NDPP), respectively. The 3 goats in each group were implanted melatonin (1.68mg/kgBW) each month. The results showed that nitrogenous compounds partitioned more to cashmere growth when treated by Short Daily Photoperiod (SDPP)or implanted melatonin than Long Daily Photoperiod(LDPP)or unimplanted melatonin goats. In Telogen, the corresponding was 36.1% of nitrogenous compounds was partitioned to fur, 63.9% were partitioned to body protein when treated with melatonin, while 33.7% of nitrogenous compounds were partitioned to fur, 66.3% were partitioned to body protein when the animal unimplanted melatonin in SDPP(P﹥0.05). In LDPP, 23.6% of nitrogenous compounds were partitioned to fur, 76.4% were partitioned to body protein when the animal were unimplanted melatonin, while 33.7% of nitrogenous compounds were partitioned to fur, 66.3% were partitioned to body protein when treated with melatonin(P﹤0.01). Nitrogenous compounds partitioning in NDPP goats was similar to that in LDPP animals, the corresponding was 35.0% of nitrogenous compounds was partitioned to fur, 65.0% were partitioned to body protein when treated with melatonin, while 24.3% of nitrogenous compounds were partitioned to fur, 75.7% were partitioned to body protein when the animal were unimplanted melatonin(P﹤0.01). Cashmere in SDPP and implanted melatonin groups growed normally in Telogen, the cashmere growed to 4.59±0.18～5.14±0.36cm in the period of 90 days, 5.01±0.31cm～5.52±0.09cm after 120 days, 5.45±0.26～6.32±0.22cm after 150 days of treatment. Average cashmere production increased more 338.8g, increased by more 73.86% than normal production(P﹤0.01), and cashmere diameter reduced from 15.22±0.12μm to 14.77±0.11μm(P﹥0.05).But cashmere strength reduced from 5.34±0.19cN to 3.97±0.27cN(P﹤0.05),which are still in the range of Texitile Standard of Classification. The body composition of Inner Mogolia White Cashmere goats treated with different length of photoperiod and melatonin were also studied in telogen by tritiated water dilution technique. Results showed that body composition was dramatically changed, fat percentage of the implanted melatonin goats in LDPP and NDPP groups were sharply higher than the non-implanted melatonin goats, the corresponding 8.32% and 7.10%, respectively(P﹤0.01). On the other hand, body protein, water, and ash percentages in the body of implanted goats were significantly decreased by 1.58%, 6.65%, 0.4% in LDPP(P﹤0.01), 2.01%, 8.02%, 0.5% in NDPP group. In SDPP group, 24.67% fat percentage for implanted goats, 23.60% for non-implanted goats were much higher than the the values in LDPP and NDPP groups(P﹤0.01); protein percentage of 12.71%, 13.07%, water percentage of 55.42%, 56.46% , and ash percentage of 3.18%, 3.26% were much lower than the unimplanted goats in LDPP and NDPP groups. But in SDPP group, these values for implanted and unimplanted goats were not significantly different(P﹥0.05). The results showed that photoperiod and melatonin were all capable to dramatically change the body composition of cashmere goats, intensive interaction between photoperiod and implanted melatonin was also observed(P﹤0.01). The level of melatonin in plasma of goats in LDPP group in days was similar to that of in NDPP and SDPP group(sP﹥0.05).But in night the plasma melatonin levels in in LDPP and NDPP groups these groups were higher than that of in NDPP group. The plasma melatonin levels in implanted groups were always higher than that of unimplanted goats in the same photoperiod(P﹤0.01), and implanted groups in S... |
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