ABSTRACT
Two experiments were conducted to evaluate reproductive responses to supplemental high-linoleate safflower seeds in postpartum beef cows. In Exp. 1, 18 primiparous, crossbred beef cows (411 +/- 24.3 kg of BW) were fed Foxtail millet hay starting 1 d postpartum at 1.68% of BW (DM basis) and a low-fat control (control: 63.7% cracked corn, 33.4% safflower seed meal, and 2.9% liquid molasses; DM basis) at 0.35% of BW (n = 9) or a supplement (linoleate) containing 95.3% cracked high-linoleate (79% 18:2n-6) safflower seeds and 4.7% liquid molasses (DM basis) at 0.23% of BW (n = 9). Beginning 1 d postpartum, blood was collected every 3 d for sera. Cows were slaughtered at 37 +/- 3 d postpartum for collection of hypothalami, anterior pituitary glands, liver, ovarian follicles, and uterine tissue. By 37 +/- 3 d postpartum, dietary treatment did not influence ovarian follicular development (P >or= 0.17), hypophyseal concentrations of LH (P = 0.14), or concentrations of IGF-I in liver (P = 0.15). In contrast, anterior pituitary glands from linoleate cows contained more FSH (P = 0.02) than control cows and linoleate cows had less IGF-I in the medial basal hypothalamus (P = 0.05), preoptic area (P = 0.06), and in follicular fluid (P Subject(s)
Carthamus tinctorius/physiology
, Cattle/physiology
, Diet/veterinary
, Dietary Supplements
, Postpartum Period
, Reproduction/physiology
, Seeds/physiology
, Animals
, Cattle/metabolism
, Estradiol/analysis
, Female
, Follicle Stimulating Hormone/analysis
, Hypothalamus/chemistry
, Insulin-Like Growth Factor I/analysis
, Liver/chemistry
, Luteinizing Hormone/analysis
, Ovarian Follicle/metabolism
, Ovarian Follicle/physiology
, Pituitary Gland/chemistry
, Pregnancy
, Progesterone/analysis
, Random Allocation
, Receptors, LHRH/analysis
, Time Factors