de Almeida Daniel Mageste, Marcondes Marcos Inácio, Rennó Luciana Navajas, Pereira Silva Luiz Henrique, Martins Leandro Soares, Marquez David Esteban Contreras, Castaño Villadiego Faider Alberto, Velez Saldarriaga Felipe, Franco Julian David Castaño, Moreno Deilen Paff Sotelo, de Moura Felipe Henrique, Paulino Mário Fonseca
Department of Animal Science, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil.
Department of Veterinary Medicine, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil.
Trop Anim Health Prod. 2019 Jan;51(1):79-87. doi: 10.1007/s11250-018-1662-z. Epub 2018 Jul 13.
The objective of this study was to evaluate the effects of strategic supplementation in the dry period and dry/rainy transition period on the performance and nutritional, metabolic, and reproductive responses of Nellore heifers grazing Urochloa decumbens. Forty-eight Nellore heifers with age and body weight (BW) of eight months and 235 ± 3.3 kg, respectively, were used. The experimental design was a completely randomized design, with four treatments, all with 12 replications. The evaluated strategies were as follows: low supplementation (LOHI; 0.2% of BW/heifer/day) in the first 90 days and high supplementation (0.6% of BW/heifer/day) in the 90 days thereafter; average supplementation (AVER) with 0.4% of BW/heifer/day for 180 days; high supplementation (HILO; 0.6% of BW/heifer/day) in the first 90 days and low supplementation (0.2% of BW/heifer/day) in the 90 days thereafter; only mineral mix (MM) ad libitum during the 180 days. Data were evaluated using orthogonal contrasts. Supplementation improved the performance of the animals during of dry period (P < 0.05) and dry/rainy transition period (P < 0.05). Supplemented animals had higher longissimus muscle area (LMA) and subcutaneous fat thickness (SFT) at the end of the experiment (P < 0.05). Multiple supplementation increased intake of dry matter (DM), organic matter (OM), and crude protein (CP) in kg/day throughout the experiment. The supplementation increased the digestibility of DM, OM, CP, apNDF, and TDN (P < 0.05). Serum urea nitrogen (SUN), glucose (GLUC), insulin (INS), and progesterone (PROG) were higher in supplemented heifers (P < 0.05). Supplementation reduced the concentrations of non-esterified fatty acids (NEFA) (P < 0.05) and increased conception rate (P < 0.05). In summary, the supplementation strategies adopted in this study improve the performance, metabolic status, and carcass traits of heifers under grazing, allowing an improvement in the conception rate of 15-month-old Nellore heifers.
本研究的目的是评估在干奶期和干/雨过渡期进行策略性补饲对放牧俯仰臂形草的内洛尔小母牛生产性能、营养、代谢和繁殖反应的影响。使用了48头内洛尔小母牛，年龄和体重分别为8个月和235±3.3千克。实验设计为完全随机设计，有四种处理，每种处理12个重复。评估的策略如下：前90天低补饲（LOHI；0.2%体重/头/天），此后90天高补饲（0.6%体重/头/天）；180天内平均补饲（AVER），0.4%体重/头/天；前90天高补饲（HILO；0.6%体重/头/天），此后90天低补饲（0.2%体重/头/天）；180天内仅自由采食矿物质预混料（MM）。数据使用正交对比进行评估。补饲提高了动物在干奶期（P<0.05）和干/雨过渡期（P<0.05）的生产性能。实验结束时，补饲的动物有更高的背最长肌面积（LMA）和皮下脂肪厚度（SFT）（P<0.05）。在整个实验过程中，多次补饲增加了干物质（DM）、有机物（OM）和粗蛋白（CP）的日摄入量（千克）。补饲提高了DM、OM、CP、酸性洗涤纤维（apNDF）和总可消化养分（TDN）的消化率（P<0.05）。补饲的小母牛血清尿素氮（SUN）、葡萄糖（GLUC）、胰岛素（INS）和孕酮（PROG）水平更高（P<0.05）。补饲降低了非酯化脂肪酸（NEFA）的浓度（P<0.05）并提高了受孕率（P<0.05）。总之，本研究采用的补饲策略提高了放牧小母牛的生产性能、代谢状态和胴体性状，使15月龄内洛尔小母牛的受孕率提高。
