We investigated the effects of chromium propionate (CrP) supplementation on reproductive performance of beef cows during the pre-partum and breeding periods. Angus-based commercial suckled beef cows were stratified by predicted calving date, body weight (BW) and randomly assigned to one of two treatments: 1) Control, (n = 30) supplementation of a corn gluten, soy hull pellet feed (50:50) with a mineral pack at 1 kg ּ cows-1 d-1; or 2) CrP, (n = 32) supplementation at 1 kgּ cow-1ּּ d-1 of a corn gluten, soy hull pellet feed (50:50) with a mineral pack containing 1.4 g of CrP (KemTRACE chromium 0.4%, Kemin Industries, Inc., Des Moines, IA). Cows remained on a single pasture equipped with feed bunks capable of monitoring individual supplement intake (SmartFeed, C-lock Inc., Rapid City, SD). Treatments were initiated at 92 d prepartum and ended on d 35 post fixed-time artificial insemination (TAI), for a total of 127 d. Cows were enrolled in the 7-d CO-Synch+CIDR TAI protocol. Ovarian ultrasonography was performed to determine diameter of the largest follicle, and the volume of a corpus luteum (CL) on d -10, -3, 0 (TAI day), and 7. Pregnancy diagnosis was performed by ultrasonography on d 35. Cow BW was recorded on d -92, 0, and 35. Data were analyzed using the GLIMMIX and MIXED procedures of SAS with cow as the experimental and fixed effect of treatment. Age, days postpartum, and initial BW were similar (P > 0.05) between treatments (7.4 and 7.2 ± 0.61 yr, 81.3 and 80.8 ± 4.61 d, 526.2 and 528.6 ± 16.21 kg for Control and CrP, respectively). Supplement intake was similar (P = 0.534) between treatments (1.22 and 1.03 gּ cow-1ּּ d-1, for Control and CrP, respectively). Cow BW was similar (P > 0.05) between treatments on d 0 and 35 (548.5 and 551.4 ± 13.50 kg, 562.8 and 574.6 ± 11.41 kg, for Control and CrP, respectively). Furthermore, estrus expression and TAI pregnancy rate was similar (P > 0.05) between treatments (62.1 and 61.1 ± 1.2% estrus, 55.1 and 81.2 ± 20.1% TAI pregnancy rate, for Control and CrP, respectively). However, CrP cows had a larger follicle (P = 0.028) on d 0 (13.79 and 15.56 ± 0.58 mm, for Control and CrP, respectively). Additionally, on d 7, CrP cows had an increased (P = 0.038) CL volume (15.24 and 17.55 ± 0.68 mm3, for Control and CrP, respectively). Supplementation of CrP to beef cows from the pre-partum until breeding did not change cow BW, but increased follicle diameter at TAI and subsequent CL volume.

中文翻译：

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231 在接受丙酸铬补充剂的同时参加固定时间人工授精的肉牛的卵泡直径和黄体体积


我们研究了丙酸铬 （CrP） 补充剂对肉牛产前和繁殖期繁殖性能的影响。以安格斯为基础的商业乳牛按预测产犊日期、体重 （BW） 进行分层，并随机分配到以下两种处理之一：1） 对照，（n = 30） 补充玉米面筋、大豆壳颗粒饲料 （50：50） 和 1 kg ּ cows-1 d-1 的矿物质包;或 2） CrP，（n = 32） 以 1 kg⼈ cow-1ּּ d-1 玉米面筋、大豆壳颗粒饲料 （50：50） 补充含有 1.4 g CrP（KemTRACE 铬 0.4%，Kemin Industries， Inc.，Des Moines，IA）的矿物质包。奶牛留在一个牧场上，该牧场配备了能够监控个体补充剂摄入量的饲料铺位（SmartFeed，C-lock Inc.，拉皮德城，南达科他州）。治疗在产前 92 天开始，在固定时间人工授精 （TAI） 后 35 天结束，共 127 天。奶牛被纳入 7-d CO-Synch+CIDR TAI 方案。进行卵巢超声检查以确定最大卵泡的直径，以及第 -10 、 -3、 0 （TAI 天） 和 7 的黄体体积 （CL）。第 35 天通过超声检查进行妊娠诊断。奶牛 BW 记录在 d -92、0 和 35。使用 SAS 的 GLIMMIX 和 MIXED 程序分析数据，奶牛作为治疗的实验和固定效果。治疗之间的年龄、产后天数和初始体重相似 （P > 0.05） （对照组和 CrP 分别为 7.4 和 7.2 ± 0.61 岁、81.3 和 80.8 ± 4.61 天、526.2 和 528.6 ± 16.21 kg）。治疗之间的补充剂摄入量相似 （P = 0.534） （对照组和 CrP 分别为 1.22 和 1.03 gּ cow-1ּּ d-1）。第 0 天和第 35 天（548.5 和 551.4 ± 13.50 kg、562）处理间奶牛体重相似 （P > 0.05）。8 和 574.6 ± 11.41 kg，分别用于对照和 CrP）。此外，不同处理之间的发情表达和 TAI 妊娠率相似 （P > 0.05） （对照组和 CrP 分别为 62.1 和 61.1 ± 1.2% 发情率，55.1 和 81.2 ± 20.1% TAI 妊娠率）。然而，CrP 奶牛在第 0 天具有较大的卵泡 （P = 0.028）（对照和 CrP 分别为 13.79 和 15.56 ± 0.58 毫米）。此外，在第 7 天，CrP 奶牛的 CL 体积增加 （P = 0.038） （对照和 CrP 分别为 15.24 和 17.55 ± 0.68 mm3）。从产前到繁殖，肉牛补充 CrP 不会改变奶牛的体重，但会增加 TAI 的卵泡直径和随后的 CL 体积。