Corro M, Rubio I, Castillo E, Galindo L, Aluja A, Galina C S, Murcia C
Centre for Research, Teaching and Extension in Tropical Animal Husbandry, Faculty of Veterinary Medicine and Zootechnics, National Autonomous University of Mexico, Veracruz, Mexico.
Prev Vet Med. 1999 Jan 27;38(2-3):101-17. doi: 10.1016/s0167-5877(98)00117-2.
Research was conducted on typical smallholder farms with dual-purpose cattle (DPC) (Bos indicus x B. taurus) in the coastal north-central area of Veracruz, Mexico. The study was divided into two phases. The aim of the first phase was to investigate the effect of blood metabolities, body condition and pasture management on milk yield and postpartum intervals, in order to investigate if the former are suitable indicators of the reproductive and nutritional status of DPC. One hundred and sixty-five calvings of crossbred cows were recorded from January 1992 to November 1994 on 12 small farms. Milk samples were collected twice a week for progesterone analysis. Blood samples and BCS were taken once a month. However, in Phase II emphasis was placed on the effect of pasture management upon reproductive and productive performance of DPC. Records of four farms were obtained from June 1995 to November 1996. Stocking rates were 0.40, 0.87, 0.35 and 1.5 cows/ha for farms A, B, C and D, respectively. Farms A and C used a slow rotation while B and D used a rapid rotation. In Phase I, the changes in BCS during the last month of pregnancy and first month postpartum did not correlate (p > 0.05) with milk yield or reproductive performance. Blood the metabolite profiles were not consistently related to productive or reproductive variables. The effect of farm and season was significant (p < 0.05) on most of the response variables and low productivity on overstocked farms lead to the conclusion that the low reproductive performance of DPC was linked to poor pasture management. During Phase II, farms A (FA) and D (FD) produce more milk than the others. Days to first service, days open, and calving interval were similar for farms B (FB) and C (FC), highest for Farm A, and lowest for Farm D. The forage availability mean was above the critical range of 6-8 kg of dry matter per 100 kg of liveweight (kg DM/100 kg LW) in all farms (range from 6.1 +/- 5.0 to 21.1 +/- 11.2 kg DM/100 kg LW). Farm D had the highest stocking rate (1.5 cows/ha), a rapid rotation (10 paddocks), a good forage availability (7.1 +/- 3.9 kg DM/100 kg LW) with a good quality for a tropical pasture (11.6 +/- 2.4% crude protein), and an economic energy supplementation. These results suggest this type of management could be more widely employed to improve the productivity of DPC on smallholder farms in the Mexican tropics.
在墨西哥韦拉克鲁斯州中北部沿海地区，对饲养兼用型牛（DPC）（印度瘤牛×欧洲牛）的典型小农户农场展开了研究。该研究分为两个阶段。第一阶段的目的是调查血液代谢物、体况和牧场管理对产奶量和产后间隔的影响，以探究前者是否为兼用型牛繁殖和营养状况的合适指标。1992年1月至1994年11月期间，在12个小农场记录了165头杂交母牛的产犊情况。每周采集两次牛奶样本用于孕酮分析。每月采集一次血液样本并进行体况评分（BCS）。然而，在第二阶段，重点关注牧场管理对兼用型牛繁殖和生产性能的影响。获取了1995年6月至1996年11月期间四个农场的记录。农场A、B、C和D的载畜率分别为每公顷0.40头、0.87头、0.35头和1.5头母牛。农场A和C采用缓慢轮牧，而农场B和D采用快速轮牧。在第一阶段，妊娠最后一个月和产后第一个月的体况评分变化与产奶量或繁殖性能无相关性（p>0.05）。血液代谢物谱与生产或繁殖变量之间没有一致的关联。农场和季节对大多数响应变量有显著影响（p<0.05），且超载农场的低生产率导致得出结论：兼用型牛的低繁殖性能与不良的牧场管理有关。在第二阶段，农场A（FA）和农场D（FD）的产奶量高于其他农场。农场B（FB）和农场C（FC）的首次配种天数、空怀天数和产犊间隔相似，农场A最高，农场D最低。所有农场的可利用牧草平均量均高于每100千克活重6 - 8千克干物质（kg DM/100 kg LW）的临界范围（范围为6.1±5.0至21.1±11.2 kg DM/100 kg LW）。农场D的载畜率最高（1.5头母牛/公顷），采用快速轮牧（10个围场），可利用牧草良好（7.1±3.9 kg DM/100 kg LW），且热带牧场质量良好（粗蛋白含量为11.6±2.4%），并有经济的能量补充。这些结果表明，这种管理方式可更广泛地应用于提高墨西哥热带地区小农户农场兼用型牛的生产力。
