Three approaches were investigated for improvement of in vitro maturation (IVM), in vitro fertilization (IVF), and early embryonic development in cattle. These were: 1) Selection of oocytes, 2) medium supplementation with fetal calf serum (FCS) and cow sera (D0, D1, D10, and D20 to correspond with estrus, metestrus, diestrus, and proestrus, respectively), and 3) addition of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and estradiol-17 beta (E2) during maturation. Greater proportions (percentage) of oocytes initially selected for their compact cumulus cells completed IVM and IVF when compared to unselected oocytes (P less than .05). Proportions (percentage) of selected oocytes that matured and cleaved after in vitro insemination according to serum type used for IVM were: FCS: 110/175 (62.9%) and 37/110 (33.6%) and D0: 130/145 (89.7%) and 52/130 (40.0%); D1 127/130 (97.7%) and 41/127 (32.3%); D10 95/98 (96.9%) and 35/95 (36.8%); D20:113/116 (97.4%) and 49/113 (43.4%). A higher proportion (P less than .05) of embryos resulting from the D20 group reached four- and eight-cell stages. In FCS-supplemented maturation media with no hormones added during maturation (control), results of IVM and IVF were 157/265 (59.2%) and 39/157 (24.8%), respectively. With E2 (1 microgram/ml) and FSH (5 micrograms/ml), comparable results were 189/215 (87.9%) and 71/189 (37.6%); with E2 (1 microgram/ml) plus LH (10 micrograms/ml), 280/327 (85.6%) and 111/280 (39.6%). Added hormones improved IVM results (P less than .05) and, when FSH or LH was added with E2, in vitro development to four- and eight-cell stages was markedly enhanced (P less than .05). Selection of oocytes, D20 serum, and added E2 and FSH or LH for IVM improved in vitro development of bovine embryos after IVF.

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Ergot alkaloids cause fescue toxicosis when livestock graze endophyte-infected (E+) tall fescue. Little is known about the bioavailability of the ergot alkaloid classes (lysergic acid, lysergic acid amides, or ergopeptine alkaloids) in livestock, and this hampers development of pharmacological strategies to ameliorate the toxicosis. One method used to determine bioavailability of ergot alkaloids is to examine urinary and biliary excretion patterns. Thus, our objectives were to compare ergot alkaloid excretion via urinary or biliary systems and to determine the rate of appearance or clearance of these alkaloids in cattle that were grazing E+ or endophyte-free (E-) tall fescue. In autumn 1996, bile and urine samples were collected from eight steers (203 kg), each grazing E+ and E- tall fescue, and total alkaloid excretion was quantified using competitive ELISA. Approximately 96% of the ergot alkaloids were excreted in urine. The same steers were used to examine the rate of appearance in, or clearance from, urine when switched from E+ to E-, or from E- to E+, pastures in comparison with steers that were continuously grazing E+ or E- tall fescue at 0, 2, 5, and 7 d. Steers were returned to their original pastures after 7 d, and urine was collected at 2, 5, and 7 d. Urinary alkaloid concentrations in steers switched from E- to E+ pastures were similar (P = .55) to those in steers that continuously grazed E+ tall fescue after 2 d. Steers switched from E+ to E- pastures had urinary alkaloid concentrations similar (P = .91) to those in steers that continuously grazed E- pastures after 2 d. In 1997, two trials were conducted in which steers (191 kg) were switched or remained on E+ or E- pastures, and urine was collected at 0, 12, 24, 48, and 96 h to estimate rate of alkaloid appearance or clearance. Steers switched from E- to E+ 1) had about 33% as much urinary alkaloids as steers grazing E+ pasture after 12 h, 2) were not different after 24 h (P = .76), 3) had twice those of the E+ steers at 48 h (P < .05), and 4) were not different after 96 h. Steers switched from E+ to E- tall fescue had approximately 33% less (P < .05) urinary alkaloids than those grazing E+ at 12 h, 67% less (P < .05) at 24 and 48 h, and were not different (P = .86) from steers continuously grazing E- pastures after 96 h. Urinary alkaloid excretion patterns were similar to ergot alkaloid solubility patterns from in vitro digestion of E+ tall fescue. We suggest that alkaloids, liberated from the forage by ruminal microorganisms, were rapidly absorbed as lysergic acid amides and biotransformed ergopeptine alkaloids.

No abstract

Non-lethal management methods are required for wild equids that are protected by law and for deer inhabiting areas where lethal controls are not legal or safe. Single or multiple inoculations of porcine zona pellucida (PZP) vaccine have been delivered to wild horses and deer by means of darts. Contraceptive efficacy in horses after two inoculations ranged from 90% to 100%, and after a single inoculation ranged from 19% to 28%. Mares given a controlled-release form of the vaccine had foaling rates ranging from 7% to 20%. No detectable changes in social organization or behaviours among treated horses occurred. Contraceptive effects were reversible after 4 consecutive years of treatment but 5-7 years of treatment resulted in ovulation failure and decreased urinary oestrogen concentrations. Among deer, two inoculations were 70-100% effective in preventing fawns, but one inoculation yielded a contraceptive efficacy of < or = 20%, with pregnancies occurring late in the breeding season; a single annual booster inoculation reduced fertility to 20% in the second year. Energy costs of extended breeding seasons were less than those resulting from pregnancy. After two years of treatment, ovaries appeared normal. These studies suggest that PZP immunocontraception can be successfully applied to certain free-roaming populations of wild horses and deer.