Absalón-Medina Victor Antonio, Blake Robert W, Fox Danny Gene, Juárez-Lagunes Francisco I, Nicholson Charles F, Canudas-Lara Eduardo G, Rueda-Maldonado Bertha L
Department of Animal Science, Cornell University, Ithaca, NY 14853, USA.
Trop Anim Health Prod. 2012 Aug;44(6):1131-42. doi: 10.1007/s11250-011-0049-1. Epub 2011 Dec 27.
Feed chemical and kinetic composition and animal performance information was used to evaluate productivity limitations and potentials of dual-purpose member herds of the Genesis farmer organization of central coastal Veracruz, Mexico. The Cornell Net Carbohydrate and Protein System model (Version 6.0) was systematically applied to specific groups of cows in structured simulations to establish probable input-output relationships for typical management, and to estimate probable outcomes from alternative management based on forage-based dietary improvements. Key herd vulnerabilities were pinpointed: chronic energy deficits among dry cows of all ages in late gestation and impeded growth for immature cows. Regardless of the forage season of calving, most cows, if not all, incur energy deficits in the final trimester of gestation; thus reducing the pool of tissue energy and constraining milking performance. Under typical management, cows are smaller and underweight for their age, which limits feed intake capacity, milk production and the probability of early postpartum return to ovarian cyclicity. The substitution of good-quality harvested forage for grazing increased predicted yields by about one-third over typical scenarios for underweight cows. When diets from first parturition properly supported growth and tissue repletion, milk production in second and third lactations was predicted to improve about 60%. Judiciously supplemented diets based on good quality grass and legume forages from first calving were predicted to further increase productivity by about 80% across a three-lactation cow lifetime. These dual-purpose herd owners have large incentives to increase sales income by implementing nutritional strategies like those considered in this study.
利用饲料化学和动力学组成以及动物生产性能信息，对墨西哥韦拉克鲁斯州中部沿海地区创世纪农民组织的两用奶牛群的生产限制和潜力进行了评估。康奈尔净碳水化合物和蛋白质系统模型（6.0版）被系统地应用于特定奶牛群体的结构化模拟中，以建立典型管理方式下可能的投入产出关系，并基于以草料为基础的日粮改良来估计替代管理方式可能产生的结果。确定了该牛群的关键脆弱点：妊娠后期所有年龄段的干奶牛长期存在能量不足，以及未成熟奶牛生长受阻。无论产犊时的草料季节如何，大多数奶牛（如果不是全部的话）在妊娠最后三个月都会出现能量不足；从而减少了组织能量储备并限制了产奶性能。在典型管理方式下，奶牛的体型和体重低于其年龄应有的水平，这限制了采食量、产奶量以及产后早期恢复卵巢周期性的可能性。用优质收获草料替代放牧，预计体重不足的奶牛的产量比典型情况提高约三分之一。如果从第一次产犊开始的日粮能适当支持生长和组织恢复，预计第二和第三泌乳期的产奶量将提高约60%。预计从第一次产犊开始就以优质禾本科和豆科草料为基础进行合理补充日粮，在奶牛的三个泌乳期内，生产力将进一步提高约80%。这些两用奶牛群的所有者有很大的动力通过实施本研究中考虑的营养策略来增加销售收入。
