Martin J L, Cupp A S, Rasby R J, Hall Z C, Funston R N
Department of Animal Science, University of Nebraska, Lincoln 68583, USA.
J Anim Sci. 2007 Sep;85(9):2298-303. doi: 10.2527/jas.2007-0076. Epub 2007 May 25.
A 2-yr study was conducted at 2 locations to determine if supplementing beef heifers with dried distillers grains (DDG) as an energy source affected growth or reproduction. Spring-born crossbred heifers (n = 316) were blocked by age or sire and age and assigned randomly to DDG or control (dried corn gluten feed, whole corn germ, urea) supplement. Heifers received prairie hay in amounts sufficient for ad libitum intake and 0.59% of BW DDG or 0.78% of BW control supplement (DM basis). Supplements were formulated to be isocaloric, but protein degradability differed. Supplemental undegradable intake protein intake from DDG averaged 267 g/animal daily and reached 318 g/animal daily; control supplemental undegradable intake protein intake averaged 90 g/animal daily and peaked at 107 g/animal daily. Initial pubertal status was determined by 2 blood samples collected 10 d apart, and monthly BW were collected from November through January; then biweekly BW and blood samples were collected from February until May yearly. Heifers were synchronized with 2 injections of PGF2alpha 14 d apart; estrus was detected and heifers were artificially inseminated for 5 d and placed with bulls 10 d later. Conception and pregnancy rates were determined via transrectal ultrasonography. Initial age, BW, and BCS did not differ (P > 0.92) for control and DDG heifers. Final BW, ADG, and final BCS also were not affected (P > 0.31) by supplementation. Estimated age and BW at puberty did not differ (P > 0.23) between treatments, and the proportions of pubertal heifers did not differ at the initiation of the experiment (P > 0.82), at the beginning of the 14-d sampling intervals, or before synchronization. Estrus synchronization rate (75.9%), time of estrus, and overall pregnancy rate (89.5%) were not affected (P > 0.14) by treatment. However, a greater proportion (P = 0.008) of DDG than control heifers conceived to AI (75.0 vs. 52.9%), resulting in greater (P = 0.07) AI pregnancy rates for DDG heifers (57.0 vs. 40.1%). Body weight or BCS at pregnancy diagnosis did not differ (P > 0.52) between DDG and control heifers. Supplementing beef heifers with DDG during development did not affect age at puberty but improved AI conception and pregnancy rates compared with an isocaloric control supplement.
在两个地点进行了一项为期两年的研究，以确定用干酒糟（DDG）作为能量来源补充肉用小母牛是否会影响其生长或繁殖。春季出生的杂交小母牛（n = 316）按年龄或父系及年龄进行分组，并随机分配到DDG组或对照组（干玉米蛋白粉、全玉米胚芽、尿素）。小母牛自由采食足量的苜蓿干草，并分别采食占体重0.59%的DDG或占体重0.78%的对照补充料（干物质基础）。补充料配方为等热量，但蛋白质降解率不同。DDG补充料中不可降解摄入蛋白的平均摄入量为每头动物每天267克，最高达到每头动物每天318克；对照补充料中不可降解摄入蛋白的平均摄入量为每头动物每天90克，最高达到每头动物每天107克。通过间隔10天采集的两份血样确定初始青春期状态，11月至1月每月采集体重，然后每年2月至5月每两周采集体重和血样。小母牛每隔14天注射两次PGF2α进行同期发情处理；检测发情情况，小母牛人工授精5天，10天后与公牛混群。通过直肠超声检查确定受孕率和妊娠率。对照和DDG小母牛的初始年龄、体重和体况评分无差异（P > 0.92）。补充料对最终体重、平均日增重和最终体况评分也无影响（P > 0.31）。各处理间青春期的估计年龄和体重无差异（P > 0.23），在实验开始时、14天采样间隔开始时或同期发情处理前，青春期小母牛的比例也无差异（P > 0.82）。处理对同期发情率（75.9%）、发情时间和总体妊娠率（89.5%）无影响（P > 0.14）。然而，DDG小母牛人工授精受孕的比例高于对照组（P = 0.008）（75.0%对52.9%），导致DDG小母牛的人工授精妊娠率更高（P = 0.07）（57.0%对40.1%）。妊娠诊断时，DDG和对照小母牛的体重或体况评分无差异（P > 0.52）。在生长发育期间用DDG补充肉用小母牛不会影响青春期年龄，但与等热量对照补充料相比，可提高人工授精受孕率和妊娠率。
