Rutter L M, Manns J G
Alberta Agriculture, Edmonton, Canada.
J Anim Sci. 1991 Mar;69(3):1140-6. doi: 10.2527/1991.6931140x.
The objective of this study was to determine whether nutrition affects follicular growth and(or) steroid and insulin-like growth factor I (IGF-I) concentrations in follicular fluid. Beginning 6 d after calving, Hereford-cross cows (n = 28) were fed either 14 (ad libitum) or 7 (restricted) kg.animal1.d-1 of chopped alfalfa-brome hay. Half the cows in each treatment were ovariectomized on d 20 (OVX-20) and the remaining half on d 35 (OVX-35) postpartum. Cow weight and condition score were recorded weekly, and blood was collected thrice weekly for determination of insulin, IGF-I, glucose, and free fatty acid (FFA) concentrations. At ovariectomy, follicular fluid from each follicle greater than or equal to 4 mm in diameter was aspirated for determination of IGF-I, progesterone (P4), and estradiol-17 beta (E2) concentrations. Restricted cows lost more weight after calving than did ad libitum cows (P less than .0001), although all cows lost similar amounts of body condition (time postpartum, P = .008). Concentrations of FFA were elevated (P less than .0001) in restricted cows from wk 2 through 5 after calving but did not change with time in ad libitum cows. Plasma concentrations of glucose were lower in restricted than in ad libitum cows (59.6 +/- .4 vs 61.8 +/- .4 mg/dl; P = .05), but insulin and IGF-I were similar (P greater than .10) between dietary treatments.(ABSTRACT TRUNCATED AT 250 WORDS)
本研究的目的是确定营养是否会影响卵泡生长以及（或）卵泡液中的类固醇和胰岛素样生长因子I（IGF-I）浓度。在产犊后6天开始，给赫里福德杂交奶牛（n = 28）分别饲喂14（自由采食）或7（限饲）kg·头⁻¹·天⁻¹的苜蓿-雀麦干草切碎物。每种处理的一半奶牛在产后第20天进行卵巢切除（OVX-20），另一半在产后第35天进行卵巢切除（OVX-35）。每周记录奶牛体重和体况评分，每周采集三次血液以测定胰岛素、IGF-I、葡萄糖和游离脂肪酸（FFA）浓度。在卵巢切除时，抽吸每个直径大于或等于4 mm卵泡的卵泡液，以测定IGF-I、孕酮（P4）和雌二醇-17β（E2）浓度。限饲奶牛产犊后体重损失比自由采食奶牛更多（P < 0.0001），尽管所有奶牛体况损失量相似（产后时间，P = 0.008）。限饲奶牛产后第2周至第5周FFA浓度升高（P < 0.0001），而自由采食奶牛的FFA浓度随时间无变化。限饲奶牛的血浆葡萄糖浓度低于自由采食奶牛（59.6 ± 0.4对61.8 ± 0.4 mg/dl；P = 0.05），但不同日粮处理间胰岛素和IGF-I相似（P > 0.10）。（摘要截断于250字）
