不同施肥时间及施氮水平对高寒草甸生物量和土壤养分的影响

采用随机区组设计,探讨了不同施肥时期及氮肥用量对三江源区高寒草甸初级生产力、植物养分及土壤养分的影响。结果表明:在施肥时间为7月10日,施肥量为150 kg·hm^-2时,地上生物量为最大值,较对照增加了2.06倍(P <0.05)。而植物氮素含量在施肥时间为7月10日,尿素用量为300 kg·hm^-2时达到最大值,较对照增加了31.18%(P <0.05)。相关性分析表明,地上生物量与植物全氮成显著正相关,施氮量与植物全氮成线性相关。施肥时间为7月10日左右时,尿素施用水平为150~300 kg·hm^-2,该类型高寒草甸初级生产力和土壤全氮都达到最大值,可作为优先氮素添加量来推荐。     

美国瑞士褐牛在塔城地区舍饲条件下的适应性研究

[目的]通过对美国瑞士褐牛在塔城地区舍饲条件下适应性的研究,为新类型的培育提供科学依据。[方法]对美国瑞士褐牛犊牛和母牛进行为期三年的饲养观察,对其生长情况、泌乳、繁殖性能、耐粗饲、耐热抗寒性能及疾病项目进行测定及统计分析。[结果]在舍饲条件下,初生重平均为35.23 kg,6月龄平均日增重为719.81 g;12月龄平均日增重为724.16 g,生长发育良好。平均繁殖成活率为81.72%;一胎平均泌乳量为3 561 kg,二胎平均泌乳量为4 267 kg,三胎平均泌乳量为4 579 kg。[结论]美国瑞士褐牛在塔城地区舍饲饲养条件下其生长发育良好,表现出了良好的适应性。     

Effects of time of year and reproductive state on the proliferation and keratinisation of bovine hoof cells

Cell proliferation and protein synthesis (keratinisation) were measured in vitro in hoof biopsy samples taken from two groups of seven heifers, the first calving in the winter and the second in the summer. Both parameters were significantly higher in summer than in winter irrespective of the heifers' reproductive state. The mean (se) measure of the rate of protein synthesis was 199 (27) dpm/microg DNA/hour in summer and 4 (1) dpm/microg DNA/hour in winter, and the equivalent values for cell proliferation (measured as DNA synthesis) were 375 (56) dpm/microg DNA/hour and 17 (4) dpm/microg DNA/hour. Changes around parturition depended on the time of the year. In the winter-calving heifers, the rates of proliferation and keratinisation increased significantly after calving from 22.3 (7.2) to 70.4 (16.6) and from 2.1 (0.7) to 12.4 (2.8) dpm/microg DNA/hour, respectively. In the summer-calving heifers, proliferation decreased from 388.2 (91.0) to 66.7 (9.6) dpm/microg DNA/hour but the rate of keratinisation did not change. Lesion scores and locomotion scores deteriorated after parturition, especially in the winter-calving group. The hooves were harder in summer than winter but their hardness was not affected by the heifers' reproductive state.     

配合施肥对牧1号苜蓿产量和品质的影响

在天山畜牧昌吉生物工程有限责任公司榆树沟良种繁育基地,土壤较瘠薄,盐碱较重的地段,进行了苜蓿配合施肥试验。结果表明:配合施肥可提高杂花苜蓿干草产量,过磷酸钙与硫酸钾配合施用干草产量最高为15 860.80 kg/hm2,高于对照36.81%;同时也提高了苜蓿粗蛋白含量,改善了苜蓿品质。尿素,过磷酸钙及硫酸钾配合施用时,前两茬草粗蛋白含量分别为19.12%和19.90%,高于对照的17.4%和12.8%;提高了苜蓿种植的经济效益,尿素与过磷酸钙配合施用时效果最好,净增1 826.55元/hm2。     

Reproductive and Endocrine Characteristics of Delayed Pubertal Ewe-Lambs after Melatonin and l-Tyrosine Administration

The investigation was carried out to study the impact of melatonin and L-tyrosine administration on the onset of cyclicity in delayed pubertal ewe-lambs. Fifteen delayed pubertal ewe-lambs (age >16 months) were used in this study after being assigned randomly into three groups. In the first group (melatonin treated group, n = 5), each lamb was administered 3 mg melatonin orally at 16:00 hours from 1 July to 15 September while in the second group (L-tyrosine treated group, n = 5), each lamb was administered L-tyrosine at the level of 100 mg/kg b.w. as a single oral dose. The third group (n = 4) served as control. Lambs were exposed to mature, fertile rams daily and blood samples were collected twice weekly. The progesterone concentrations (P4 evaluations) were significantly higher (p < 0.05) in treated groups than the control group. Ovarian activity, assessed by P4 evaluations, showed that all animals in the first group came in oestrus and from them four got pregnant (80%) while in the second group, only three lambs came in heat and from them two became pregnant (40%). On the contrary, none of the control lambs showed oestrus. In conclusion, this study confirmed that the oral administration of melatonin and L-tyrosine played an essentially physiological roles to induce cyclicity in delayed pubertal ewe-lambs and improved their reproduction.