TY - JOUR TI - Antagonistic effects of Dopram-V on xylazine and acepromazine in dogs AU - Short, C. E. AU - Gleed, R. AU - Bristol, D. G. AU - Meyer, R. AU - Harvey, R. T2 - Veterinary Medicine and Small Animal Clinician DA - 1982/// PY - 1982/// VL - 77 SP - 1761-1764 ER - TY - JOUR TI - Sexual behavior and testicular development in purebred and crossbred boars AU - Neely, J. D. T2 - Dissertation Abstracts International. B, Sciences and Engineering DA - 1982/// PY - 1982/// VL - 43 IS - 6 SP - 1673 ER - TY - JOUR TI - RELATIONSHIPS BETWEEN ENDOGENOUS GONADOTROPIN-RELEASING HORMONE, GONADOTROPINS, AND FOLLICULAR DEVELOPMENT AFTER WEANING IN SOWS AU - COX, NM AU - BRITT, JH T2 - BIOLOGY OF REPRODUCTION AB - Two experiments were conducted to examine relationships between endogenous gonadotropinreleasing hormone (GnRH), concentrations of gonadotropins in the anterior pituitary and blood and ovarian follicular development in weaned sows. In the first experiment, 48 sows were slaughtered during 0 to 5 days after weaning. Because effects of breed, parity, farm and season of slaughter were confounded with day after weaning, data were analyzed solely on the basis of follicular development. Sows were divided into 4 groups based on the size and number of the largest ovarian follicles. Group 1 consisted of 11 sows with largest follicles <5 mm in diameter. Sows (n=1 1) in Group 2 had few (≤10) follicles 5 to 10 mm in diameter, and sows (n=11) in Group 3 had many (≥14) follicles 5 to 10mm in diameter. Group 4 coniisted of sows (n=12) with follicles >10 mm in diameter. Data from 3 sows that had ovulated were omitted from the analyses. Sows in Groups 1, 2, 3 and 4 were killed atm average of 0.7 ± 0.4, 2.5 ± 0.2, 4.7 ± 0.1 and 4.8 ± 0.2 days after weaning, respectively. Concentrations of GnRH in medial basal hypothalamus (MBH), stalk median eminence (SME) and hypophyseal portal area (HPA) were greater in sows with greater follicular development (Groups 3 and 4). Concentrations of luteinizing hormone (LH) in anterior pituitary (AP) and serum were also greater in Groups 3 and 4. Concentrations of follicle-stimulating hormone (FSH) in AP and serum were not significantly different among groups. In the second experiment, 27 second parity Duroc sows were slaughtered 0, 60 or 96 h after weaning (9 sows per group). Concentrations of both LH and FSH in serum samples obtained at 6-h intervals from weaning to slaughter increased after weaning, and by 96 h levels of LH indicated a preovulatory surge was beginning. Follicular diameter increased with time after weaning, with increases in number of follicles ≥5 mm in diameter, and decreases in number of follicles <5 mm in diameter. Concentrations of LH, but not FSH, in AP were greater at both 60 and 96 h than at 0 h after weaning (P<0.01). Concentrations of GnRH in MBH and SME were greater at 60 and 96 h than at 0 h (P<0.05). The concentration of GnRH in HPA was increased only at 96 h after weaning. In both experiments, concentration of GnRH increased after weaning, concurrently with postweaning increases in serum FSH, serum and pituitary LH and follicular development. Thus we propose that initiation of estrus and ovulation after weaning may be associated with changes in production of GnRH. DA - 1982/// PY - 1982/// DO - 10.1095/biolreprod27.1.70 VL - 27 IS - 1 SP - 70-78 SN - 0006-3363 ER - TY - JOUR TI - PULSATILE ADMINISTRATION OF GONADOTROPIN-RELEASING HORMONE TO LACTATING SOWS - ENDOCRINE CHANGES ASSOCIATED WITH INDUCTION OF FERTILE ESTRUS AU - COX, NM AU - BRITT, JH T2 - BIOLOGY OF REPRODUCTION AB - Two experiments were conducted to determine whether pulsatile administration of gonadotropin releasing hormone (GnRH) would induce estrus and ovulation in lactating, anestrous sows. In each experiment, six lactating sows received GnRH, i.v. (2.5 µg every 2 h, Exp. 1; 1.5 µg every h, Exp. 2) until 24 h after estrus or 7 days, whichever came first. In Experiment 1, three of six GnRH-treated lactating sows exhibited estrus 4.0 ± 0.0 days after GnRH treatment began. All three GnRH-treated sows conceived at the estrus induced during lactation. Patterns of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in serum around estrus were similar between GnRH-treated sows that exhibited estrus during lactation and weaned control sows. However, in GnRH-treated sows that did not show estrus, a preovulatory-like surge in FSH, but not in LH, occurred on Day 4 of GnRH treatment. Prolactin concentrations in serum dropped from 25.6 ± 2.4 ng/ml during lactation to less than 6 ng/ml within 12 h after weaning (Exp. 1). In Experiment 2, all six GnRH-treated sows exhibited estrus 3.8 ± 0.3 days after initiation of GnRH treatment, and five sows conceived. Patterns of LH and FSH during lactation were similar between GnRH-treated and lactating control sows during the first 3 days of GnRH treatment. During 3 days before estrus, LH concentrations were lower (P<0.05) and FSH concentrations tended to be higher (P<0.20) in lactating GnRH-treated sows than in control sows whose litters had been weaned. Concentrations of estradiol in GnRH-treated sows were greater than those in controls during lactation but were similar in both groups on the day of estrus. In both experiments, concentrations of progesterone were greater in GnRH-treated than in control sows prior to and during estrus. We conclude that, despite some differences in hormone secretion between GnRH-treated lactating sows and sows with litters weaned, pulsatile administration of GnRH caused requisite endocrine changes for fertile estrus during lactation. DA - 1982/// PY - 1982/// DO - 10.1095/biolreprod27.5.1126 VL - 27 IS - 5 SP - 1126-1137 SN - 0006-3363 ER - TY - JOUR TI - Hormonal determinants of estrus during and after lactation in the postpartum sow AU - Cox, N. M. T2 - Dissertation Abstracts International. B, Sciences and Engineering DA - 1982/// PY - 1982/// VL - 43 IS - 3 ER - TY - JOUR TI - EFFECT OF FEEDING WET BREWERS GRAINS TO BEEF HEIFERS ON WINTERING PERFORMANCE, SERUM SELENIUM AND REPRODUCTIVE-PERFORMANCE AU - CRICKENBERGER, RG AU - JOHNSON, BH T2 - JOURNAL OF ANIMAL SCIENCE AB - Wet brewers grains (WBG) were evaluated as a feed source for growing Angus heifers (201 kg, 313 d of age) during a 112-d wintering trial. Effects on growth, feed efficiency, serum Se and first breeding performance were examined. Three replications of four heifers each were fed the following diets: (1) corn silage with no protein supplement (CSNS); (2) corn silage plus 33.8% of the diet dry matter (DM) from WBG (CSWBG), and (3) WBG, corn and fescue hay at 62.2, 10.8 and 26.1% of diet DM, respectively (WBGCH). Average daily gains for heifers fed CSNS, CSWBG and WBGCH were .50, .73 and .56 kg/head (P< .05), and DM:gain ratios were 9.52, 6.34 and 6.13 (P<.05), respectively. Serum Se concentrations were higher (P<.01) in heifers fed diets containing WBG than in heifers fed CSNS. Serum Se concentrations were also influenced by sampling time (P<.01) and the diet × samppling time interaction (P<.05). At the end of the trial, serum Se concentrations were .050, .085 and .105 ppm (P<.01), respectively, for heifers on the three dietary treatments. Following a 66-d breeding period, 12 of 12 heifers fed CSNS and WBGCH diets and 10 of 12 heifers fed CSWBG were diagnosed pregnant and subsequently calved. DA - 1982/// PY - 1982/// DO - 10.2527/jas1982.54118x VL - 54 IS - 1 SP - 18-22 SN - 0021-8812 ER - TY - JOUR TI - EFFECT OF ESTRADIOL ON HYPOTHALAMIC GNRH AND PITUITARY AND SERUM LH AND FSH IN OVARIECTOMIZED PIGS AU - COX, NM AU - BRITT, JH T2 - JOURNAL OF ANIMAL SCIENCE AB - Two experiments were conducted to measure pituitary gonadotropins, hypothalamic-gonadotropin releasing hormone (GnRH) and pituitary response to GnRH during periods when serum luteinizing hormone (LH) was suppressed by estradiol-17 beta (e2) in ovariectomized pigs. In the first experiment, 10 ovariectomized gilts were assigned to two groups of five each according to time of slaughter (24 or 36 h after injection). Within each group, gilts were given corn oil (n = 2) or 400 micrograms E2 (n = 3). Neither serum nor anterior pituitary (AP) concentrations of follicle-stimulating hormone (FSH) were affected by E2. Serum LH was suppressed from 12 to 26 h after E2. Concentrations of LH in AP were unchanged at 24 h, but increased at 36 h after E2 injection. Concentrations of GnRH in medial basal hypothalamus (MBH), stalk-median eminence (SME) and hypophyseal portal area (HPA) were lower at 24 h after E2 than in oil-treated gilts. At 36 h after E2, suppressive effects of E2 on LH in serum had subsided and concentrations of LH in AP and GnRH in MBH and SME were greater than in oil-treated controls. The observation that E2 suppressed LH in serum without a detectable suppression of LH in AP led to the hypothesis that E2 had caused the suppression of serum LH by suppression of GnRH release. In a second experiment, 12 ovariectomized gilts were assigned to receive corn oil (n = 4), 400 micrograms E2 (n = 4) or 400 micrograms E2 plus GnRH (1.5 micrograms/h; n = 4). Patterns of LH in sera of E2-treated animals were similar to those in the first experiment, with serum LH in E2-treated gilts suppressed from 4 to 32 h after treatment. However, in gilts receiving GnRH in addition to E2, serum LH concentrations during 20 to 32 h after treatment were intermediate between gilts receiving E2 alone and controls. Thus the pituitary of the pig is capable of responding to GnRH when LH is normally suppressed by E2. These experiments provide two lines of evidence that suppression of serum LH by E2 is due at least in part to suppression of GnRH. These experiments also establish the hypothalamus as a site for negative feedback of E2 in the female pig. DA - 1982/// PY - 1982/// DO - 10.2527/jas1982.554901x VL - 55 IS - 4 SP - 901-908 SN - 0021-8812 ER - TY - JOUR TI - ADDITIVE, NON-ADDITIVE AND MATERNAL GENETIC-EFFECTS ON ADIPOSITY IN MICE FED DIFFERENT LEVELS OF FAT AU - DEODATO, AD AU - EISEN, EJ AU - LEATHERWOOD, JM T2 - CANADIAN JOURNAL OF GENETICS AND CYTOLOGY AB - Polygenic obese (M16), nonobese (ICR) and reciprocal crossbred (M16 male x ICR female and ICR male x M16 female) mice were fed ad libitum diets containing 1, 5 or 25% fat from 3 to 10 weeks of age. Epididymal and subcutaneous fat depot weights (E, S) and depot weights as a proportion of empty body weight (E%, S%) were used as measures of adiposity at 6 and 10 weeks of age. Genetic differences in adiposity among the four populations were partitioned into average direct (a), average maternal (m) and direct heterotic (h) effects. Line M16 was greater than ICR at both 6 and 10 weeks in E (81% at 6 weeks and 114% at 10 weeks), S (82%, 73%), E% (27%, 37%) and S% (26%, 12%). Average direct genetic effects, as determined by a, accounted for 60% of the M16 vs. ICR line difference in E and S at six weeks, the remainder of the difference being due to m. The major portion of the line difference in E% and S% at 6 weeks was accounted for by m. At ten weeks of age, most of the line difference in E, S, E% and S% was due to additive direct genetic effects while the contribution of maternal genetic effects was negligible. Heterosis was sizeable for all measures of adiposity, varying from 10.8% in S% at 10 weeks to 26.8% in E at six weeks, possibly indicating the presence of directional dominance. E and E% increased significantly with the increase in dietary fat percent, but S and S% were not affected. Interactions of genotype with level of dietary fat percent were not significant for the epididymal or subcutaneous fat depot weights or proportional weights. DA - 1982/// PY - 1982/// DO - 10.1139/g82-037 VL - 24 IS - 3 SP - 347-360 SN - 0008-4093 ER - TY - JOUR TI - A NOTE ON A COMPUTER-PROGRAM FOR INDEPENDENT CULLING AU - SAXTON, AM T2 - ANIMAL PRODUCTION AB - ABSTRACT Calculating optimal truncation values for independent culling selection procedures has been difficult. Previously published charts took much of the tedium out of the calculations but the charts are difficult to read with accuracy and are not available for all possible parameter values. Therefore a computer program was written to calculate optimal truncation values for two-trait independent culling, with the option of restricting the genetic change of one or both traits. The program is described and an example of its use is given. DA - 1982/// PY - 1982/// DO - 10.1017/S0003356100027513 VL - 35 IS - OCT SP - 295-297 SN - 0003-3561 ER - TY - JOUR TI - The effects of high environmental temperature on fetal development and selected physiological variables in three breeds of sheep AU - Ross, T. T. T2 - Dissertation Abstracts International. B, Sciences and Engineering DA - 1982/// PY - 1982/// VL - 43 IS - 3 SP - 569 ER - TY - JOUR TI - SUPPRESSION OF LUTEINIZING-HORMONE AND TESTOSTERONE SECRETION IN BULLS FOLLOWING ADRENOCORTICOTROPIN HORMONE-TREATMENT AU - JOHNSON, BH AU - WELSH, TH AU - JUNIEWICZ, PE T2 - BIOLOGY OF REPRODUCTION AB - The present investigation was conducted to evaluate the inhibitory effects of adrenal corticosteroids on testosterone production by the bull testis. Administration of a single i.v. dose of adrenocorticotropic hormone (ACTH; 80 IU) resulted in a corticosteroid peak which lasted approximately 6 h. During this 6 h period, no episodic increases in secretion of LH or testosterone were initiated and basal concentrations of testosterone were suppressed (P<0.05) below control values. Episodic secretion of LH and testosterone resumed 6–7 h after ACTH when concentrations of serum corticosteroids had returned to basal levels. These results suggest that ACTH-induced increases in serum corticosteroids suppress the episodic secretion of LH, resulting in a suppression of testosterone secretion by the bull testis. DA - 1982/// PY - 1982/// DO - 10.1095/biolreprod26.2.305 VL - 26 IS - 2 SP - 305-310 SN - 1529-7268 ER - TY - JOUR TI - BREED PRENATAL, BREED POSTNATAL AND HETEROSIS EFFECTS FOR PREWEANING TRAITS IN SWINE AU - TOELLE, VD AU - ROBISON, OW T2 - JOURNAL OF ANIMAL SCIENCE AB - Crossfostering techniques were used to evaluate breed prenatal, breed postnatal and heterosis effects in Duroc and Yorkshire swine. Survival rate, individual weights at 0, 21 and 42 d, and weight gains from 0 to 21, 0 to 42, and 21 to 42 d were analyzed. When crossbred pigs were produced, prenatal effects were larger for Durocs for survival (P<.01) and all weight traits (P<.10). When purebred pigs were produced, Durocs had significantly larger breed prenatal effects for birth weight (P<.05). Yorkshires, rearing crossbred pigs, had larger (P<.10) breed postnatal effects than Durocs for all preweaning traits except survival and birth weight. When rearing purebred pigs, breed postnatal effects for Yorkshires were larger (P>.10) for all traits except birth weight. This suggests that crossbred pigs may provide a suckling stimulus or a demand to which a Yorkshire nurse is more responsive than a Duroc nurse. Heterosis values ranged from 5.6% for birth weight to 16.9% for 21-to 42-d wt gain. Yorkshires had larger breed postnatal effects than Durocs for 0 to 21-d litter gain (P<.10), 42-d litter wt (P<.05) and 0 to 42-d litter gain (P<.05). However, breed postnatal effects were not significantly different for 21-d litter weight. This suggests that 21-d litter wt may not be the best estimate of postnatal maternal performance. DA - 1982/// PY - 1982/// DO - 10.2527/jas1982.552263x VL - 55 IS - 2 SP - 263-273 SN - 0021-8812 ER - TY - JOUR TI - EFFECT OF ALTERING SUCKLING INTERVALS OF EARLY-WEANED PIGS ON REBREEDING PERFORMANCE OF SOWS AU - BRITT, JH AU - LEVIS, DG T2 - THERIOGENOLOGY AB - Sows on two commerical farms were assigned to have their pigs weaned after a 3-week lactation (control, n=160) or after a 3-week lactation that included a 48-hr period of interrupted nursing before weaning (altered-suckling, n=122). Sows in the altered-suckling groups were paired, and each member of a pair was separated from both litters during the alternate 12-hr periods. Thus during the final 48 hr before weaning, each sow in the altered-suckling group had two 12-hr periods when no litters were present and two 12-hr periods when two litters were present. On farm 1, interval from weaning to estrus was 12.8 ± 0.8 days for control sows compared to 8.4 ± 1.0 days for sows in the altered-suckling group (P<.01). On farm 2, interval from weaning to estrus did not differ between sows in the control group and those in the altered-suckling group (6.2 vs 6.1 days, P>.05). Thus altered-suckling was effective in reducing the interval from weaning to estrus only when the normal rebreeding interval was prolonged (farm 1). Conception rates at first breeding and subsequent litter sizes did not differ between treatments. Altered-suckling may improve reproductive performance of sows in situations where prolonged postweaning anestrus is a problem. DA - 1982/// PY - 1982/// DO - 10.1016/0093-691X(82)90104-2 VL - 18 IS - 2 SP - 201-207 SN - 0093-691X ER - TY - JOUR TI - Single trait and index selection for litter size and body weight in guinea pigs AU - Quijandria, B., Jr. T2 - Dissertation Abstracts International. B, Sciences and Engineering DA - 1982/// PY - 1982/// VL - 43 IS - 6 SP - 1673 ER - TY - JOUR TI - GENETIC-PARAMETERS FOR TESTES SIZE AND SPERM NUMBER IN HEREFORD BULLS AU - NEELY, JD AU - JOHNSON, BH AU - DILLARD, EU AU - ROBISON, OW T2 - JOURNAL OF ANIMAL SCIENCE AB - Paternal half-sib heritability and genetic correlation estimates were obtained utilizing data from 578 Hereford bulls from 66 sires. Bulls were maintained in three lines (weaning weight, postweaning gain and control) of an ongoing selection project. Growth performance traits studied were adjusted 205-d weaning weight, 365-d weight, individual feed efficiency, sonoray fat thickness and postweaning gain. Heritability estimates for these traits were . 15 ± .17, .33 ± .19, .46 ± .21, .28 ± .18 and .52 ± .21, respectively. Scrotal measurements taken were circumference of both testes and length and diameter of right testis at 205 and 365 d of age. Heritability estimates were .08 ± .20, .07 ± .20 and .28 ± .24 at 205 d, and .44 ± .24, .16 ± .21 and .40 ± .24 at 365 d, respectively. Excised testes traits, circumference, right testis length, diameter and weight, total sperm in the testes and sperm/gram of testes had heritability estimates of .21 ± .26, .19 ± .26, .02 ± .24, .63 ± .27, .14 ± .21 and −.13 ± .18, respectively. Genetic correlations of scrotal measurements at 205 d with scrotal measurements at 365 d and excised testes traits were negative. Scrotal measurements at 365 d had high positive genetic correlations with excised testes size, weight and total sperm. These relationships suggest that selection for increase of scrotal size at 365 d should increase testes size and weight and sperm numbers. Genetic correlations of weights and gain with scrotal measurements at 365 d and excised testes characteristics were moderate to high, in a favorable direction. Genetic correlations of testes traits with feed efficiency were essentially zero, while those with fat thickness were moderately positive. These results suggest that increasing testes size should not adversely affect growth performance traits except through the reduction in selection intensity. DA - 1982/// PY - 1982/// DO - 10.2527/jas1982.5551033x VL - 55 IS - 5 SP - 1033-1040 SN - 0021-8812 ER -