Sprinkle James E, Schafer David W, Cuneo S Peder, Tolleson Douglas R, Enns R Mark
Department of Animal and Veterinary Sciences, University of Idaho, Moscow, ID.
University of Idaho Nancy M. Cummings Research, Extension and Education Center, Carmen, ID.
Transl Anim Sci. 2020 Dec 24;5(1):txaa232. doi: 10.1093/tas/txaa232. eCollection 2021 Jan.
The objectives were to determine if strategic supplementation of range cows in central Arizona with either two or four long acting (6 mo) trace mineral rumen boluses containing Cu, Se, and Co would: 1) decrease yearly calving interval; 2) increase cow body condition, milk production, or calf adjusted weaning weights; and 3) to see if any of the above traits varied by cow breed. There were 194 Hereford (H) and 132 Composite (CGC; 50% Red Angus, 25% Tarentaise, 25% Charolais) control cows, 173 H and 125 CGC 1X treated (2 boluses in late winter) cows, and 183 H and 117 CGC 2X treated (2 boluses in autumn and 2 in late winter) cows used over the 4-yr period. Cows were weighed and scored for body condition (1-9, 9 = fattest) in February, May, and September of each year. Milk production was determined by weigh-suckle-weigh on a subset of cows ( = 169) at an average of 50 d lactation. The outcomes were analyzed using a restricted maximum likelihood-based mixed-effects model that included the categorical, fixed effects of breed, bolus, and year with the interactions of breed × bolus, and breed × year. For adjusted weaning wt (WW), year × bolus was added. The random effect of cow was also included. Calving interval had only the breed × bolus interaction added to the main effects. Age of dam was added as a covariate to all models. Milk production used the same model as calving interval with the added covariate of postpartum interval. Cow body condition score and calf adjusted weaning weights differed by breed and treatment ( < 0.05) with WW being greater ( < 0.05) for calves from 2X cows than for control calves. Milk production differed by year ( 0.0001) but did not differ by either breed or treatment ( > 0.05). Calving interval was 389 ± 2.7, 382 ± 3.2, and 378 ± 3.2 d for control, 1X, and 2X treatments, respectively and calving interval declined ( < 0.05) from the control to the 2X treatment group. Strategic supplementation via a long-acting trace mineral bolus was successful in decreasing calving interval and increasing calf-weaning weights from cattle grazed in an extensive rangeland environment.
研究目的是确定在亚利桑那州中部，给放牧母牛战略性地补充含有铜、硒和钴的两种或四种长效（6个月）微量矿物质瘤胃丸剂是否会：1）缩短年产犊间隔；2）改善母牛体况、提高产奶量或增加犊牛校正断奶体重；3）观察上述任何性状是否因母牛品种而异。在4年期间，共使用了194头赫里福德（H）对照母牛和132头复合品种（CGC；50%红安格斯、25%塔朗泰斯、25%夏洛来）对照母牛，173头H品种和125头CGC品种的1倍剂量处理（冬末投放2丸）母牛，以及183头H品种和117头CGC品种的2倍剂量处理（秋季投放2丸，冬末投放2丸）母牛。每年2月、5月和9月对母牛进行称重并评定体况（1 - 9分，9分为最肥）。通过对一部分母牛（n = 169）在平均泌乳50天时进行称重 - 哺乳 - 称重来测定产奶量。使用基于限制最大似然法的混合效应模型分析结果，该模型包括品种、丸剂和年份的分类固定效应以及品种×丸剂和品种×年份的相互作用。对于校正断奶体重（WW），模型中加入了年份×丸剂的相互作用。还纳入了母牛的随机效应。产犊间隔的主效应模型中仅加入了品种×丸剂的相互作用。将母牛年龄作为协变量纳入所有模型。产奶量使用与产犊间隔相同的模型，并加入产后间隔作为协变量。母牛体况评分和犊牛校正断奶体重因品种和处理而异（P < 0.05），2倍剂量处理母牛所产犊牛的WW更高（P < 0.05）。产奶量因年份而异（P = 0.0001），但不因品种或处理而异（P > 0.05）。对照、1倍剂量处理和2倍剂量处理的产犊间隔分别为389 ± 2.7天、382 ± 3.2天和378 ± 3.2天，从对照处理组到2倍剂量处理组产犊间隔缩短（P < 0.05）。在广阔的放牧环境中，通过长效微量矿物质瘤胃丸剂进行战略性补充成功缩短了产犊间隔并增加了犊牛断奶体重。
