Programa de Pós-Graduação Em Ciência Animal, Centro de Ciências Agroveterinárias, Universidade Do Estado de Santa Catarina, CAV/UDESC, Lages, Santa Catarina, Brazil.
Graduandos Do Curso de Medicina Veterinária Do Centro de Ciências Agroveterinárias - Universidade Do Estado de Santa Catarina, CAV/UDESC, Lages, Santa Catarina, Brazil.
Int J Biometeorol. 2022 Apr;66(4):791-801. doi: 10.1007/s00484-021-02237-3. Epub 2022 Jan 7.
The aim of this study was to evaluate the rumination time, activity index, milk yield (MY), physicochemical milk characteristics, and physiological indicators of pure Holstein (H) and first (F1- ½ Holstein × Jersey) and second-generation (R1- ¾ Holstein × ¼ Jersey) of crossbred cows in a pasture-based system under the influence of different temperature-humidity indexes (THI). Twenty-two multiparous cows (H = 7, F1 = 5, and R1 = 10) were evaluated throughout 1-year period. Daily information on rumination time and activity index was obtained using the software HealthyCow24® and the daily THI was determined from data logger information. Weekly, MY, physicochemical milk characteristics, body weight, body condition score, and physiological indicators were evaluated. THI were grouped into six classes from safe (< 68) to emergency (≥ 84). Variance analyses were performed. There was no interaction between the genetic group and THI classes for any trait. The rumination time was longer for crossbred R1 and F1 cows than for Holstein cows. The activity index increased, and rumination time decreased as the THI classes increased. There was no difference in MY between the genetic groups, but crossbred cows showed higher milk fat and protein content. Our study indicated that the high THI increases the activity index and decreases the rumination time, MY, and the physicochemical quality of milk, BW, BCS, RF, and RT of the three genetic groups (H, F1, and R1).
本研究旨在评估在不同温湿度指数（THI）影响下， pasture-based 系统中纯荷斯坦牛（H）、第一代（F1- ½荷斯坦牛×泽西牛）和第二代（R1- ¾荷斯坦牛×¼泽西牛）奶牛的反刍时间、活动指数、产奶量（MY）、乳的理化特性和生理指标。22 头经产奶牛（H 组 7 头，F1 组 5 头，R1 组 10 头）在 1 年的时间里接受了评估。使用 HealthyCow24®软件获得了反刍时间和活动指数的日常信息，每日 THI 由数据记录器信息确定。每周评估产奶量、乳的理化特性、体重、体况评分和生理指标。THI 分为安全（<68）到紧急（≥84）6 个等级进行方差分析。遗传组与 THI 等级之间没有任何性状的相互作用。与荷斯坦牛相比，杂交牛 R1 和 F1 的反刍时间更长。随着 THI 等级的增加，活动指数增加，反刍时间减少。遗传组之间的产奶量没有差异，但杂交牛的乳脂和蛋白质含量更高。我们的研究表明，高 THI 增加了活动指数，降低了反刍时间、产奶量、乳的理化质量、BW、BCS、RF 和 RT（H、F1 和 R1）。
