Progesterone levels and litter performance of sows following postpartum administration of prostaglandin F(2alpha)

A total of 101 sows was used to examine postpartum progesterone levels and litter performance following administration of 15 mg prostaglandins F(2alpha) (PGF(2alpha) n = 48) given within 12 h after farrowing. Daily blood samples and rectal temperatures were taken from all sows during the first 3 d post partum. Plasma progesterone (P(4)) concentrations were determined by radioimmunoassay (RIA). Regardless of treatment, plasma P(4) levels for all sows decreased in a similar fashion over the 3 d sampled. Mean (+/- SEM) P(4) on Day 2 (0.55 +/- 0.06 ng/ml) and Day 3 (0.38 +/- 0.04 ng/ml) were lower (P<0.01) than on Day 1 (0.98 +/- 0.08 ng/ml). Rectal temperature did not differ between PGF(2alpha) treated and nontreated sows nor was it different over the days measured. Litter characteristics, including survival rates on Day 7 and at weaning, and body weight on Days 3 and 35, were not affected by treatment. It was concluded that PGF(2alpha) administration to sows within 12 h post farrowing had no affect on the rate of luteal regression, as determined by P(4) concentration, nor on subsequent litter performance.     

The role of endogenous estrogens in the maturation process of the bovine placenta

The plasma estrogen and progesterone concentrations of 19 pregnant cows (average duration of pregnancy 266.0 +/- 2.3 d at the start of the study) were determined daily from Day 6 pre partum to Day 1 post partum. Parturition was induced in all cows by administration of 10 mg i.m. flumethasone. Values were centered around the delivery date (Day 0) following either induced normal calving (n = 3) or surgical delivery (n = 16). In animals showing spontaneous expulsion of the fetal membranes (Group 1, n = 6) the average total estrogen concentration increased significantly from Day 6 until Day 1 before parturition (1329.2 +/- 317.9 to 3719.8 +/- 951.2 pg/ml in total estrogens). A marked decrease was observed on Day 1 post partum (459.4 +/- 344.2 pg/ml). In comparison with Group 1, animals showing either a delayed or partial expulsion of the fetal membranes, or in which the placenta could be withdrawn 16 h after calving (Group 2, n = 5), had consistently lower total estrogen concentrations between Day 6 (595.4 +/- 174.8 pg/ml) and Day 1 (1884.3 +/- 565.1 pg/ml) before parturition. The estrogen values of the cows with retained placenta (Group 3, n = 8) from Days 6 to 0 pre partum were significantly lower than those of Group 2. Total estrogen concentrations of the three groups 1 d post partum did not differ significantly. It is generally recognized that estrogens play an important role in the maturation process of the placentomes. Our investigation demonstrates that not only is the magnitude of the prepartum rise in estrogens of great influence of the maturation process but the duration of this rise is likewise important. These two factors are vital for a normal expulsion of the fetal membranes.     

The effects of cervical dilation on plasma PGFM, progesterone and the duration of luteal function in diestrous mares

Transcervical diagnostic techniques may alter the length of the equine estrous cycle and affect subsequent luteal function. Therefore, nine mares were used to determine the effect of cervical dilation on plasma 13, 14-dihydro, 15-keto-prostaglandin F(2) (PGFM), progesterone (P(4)) and posttreatment duration of luteal function. Mares were given a daily score of 0 to 4 based on sexual receptivity. Five days following the end of receptivity, mares were randomly assigned to one of three, 3 x 3 latin squares. Control mares received no cervical dilation. Cervically stimulated mares recieved cervical dilation for 60 sec. Cervically stimulated plus inhibitor mares were dilated similarly to cervically stimulated mares, but received a prostaglandin synthetase inhibitor 30 min prior to treatment. Each mare completed all three treatments in three consecutive estrous cycles. Plasma PGFM and P(4) were determined by RIA. Plasma PGFM was lower (P<0.05) in cervically stimulated plus inhibitor than control and cervically stimulated mares. In addition, plasma P(4) was lower (P<0.10) in cervically stimulated plus inhibitor than in control and cervically stimulated mares. Luteal function following treatments did not differ. These data indicate that neither plasma PGFM and P(4) nor the duration of luteal function were affected by cervical dilation. However, administration of a prostaglandin synthetase inhibitor prior to cervical dilation decreased plasma PGFM and P(4) concentrations.     

Toxicity effects of latex gloves on boar spermatozoa

It is known that several materials used in semen collection have been found to be detrimental to spermatozoal motility. In this study, examinations for toxic effects of latex and vinyl gloves, used with and without talcum powder on boar spermatozoa, were performed. Ten boars of known fertility with >/=80% sperm motility were divided into two groups (n = 5 boars each) for in vitro and in vivo studies. In the in vitro study, semen was collected from each of the five boars and was divided into five separate aliquots (5 ml each). One aliquot from each of the boars remained as the control, while the remaining aliquots were divided into individual treatments exposing the semen to a l cm(2) piece of latex or vinyl glove with or without talcum powder. In the in vivo experiment, semen from each of the five boars was collected using a gloved hand. During collection, the first half of the sperm-rich fraction was collected into a filtered sterile container, while the second half of the fraction was allowed to run through the palm of either a latex or vinyl powdered glove prior to collection in the container. In both experiments, semen sample motility was assessed by two independent observers at 1 minute after exposure. Results of both experiments consistently showed a significant (P<0.05) effect of latex gloves (with or without talcum powder) on boar semen when compared with the control semen. Motility was at or near 0% at 1 min after exposure to latex. No significant difference (P>0.05) in motility was observed between the control semen and the semen exposed to talcum powdered vinyl gloves. These results show that latex gloves are detrimental to boar spermatozoa. Therefore, it is suggested that when collecting boar semen vinyl gloves should be used.     

Fertility of Bos indicus and Bos indicus x Bos taurus crossbreed cattle after estrus synchronization

Ninety-five cows (79 Boran and 16 Boran-Brahman crossbreeds) and 107 heifers (55 Boran and 52 Boran x Friesian F1 crossbreeds) were used to determine estrus response, estrus response interval and pregnancy rate following synchronization with prostaglandin (PGF(2)alpha), a progesterone-releasing intravaginal device (PRID) and Synchro-mate B (SMB). The proportion of cattle responding to synchronization treatment was 62.5, 43.5 and 57.7% for cows and 85.7, 68.0 and 81.5% for heifers using PGF(2)alpha, PRID and SMB, respectively. The overall mean response was 59 and 81.8% for cows and heifers, respectively. The estrus response of the control animals over a 45-d breeding period was 72.7 and 90% for cows and heifers, respectively. The estrus response interval for cows was 31.8, 22.1 and 18.0 h and it was 51.1, 38.0 and 21.6 h for heifers with PGF(2)alpha, PRID and SMB treatment, respectively. Mean pregnancy rate for cows was 50.0, 34.8, 46.2 and 68.8% and for heifers it was 60.7, 40.0, 55.6 and 77.8% in the PGF(2)alpha, PRID, SMB and control groups, respectively. Based on these findings, it was concluded that both PGF(2)alpha and SMB produce a satisfactory estrus response and pregnancy rate in the cattle studied.     

Ultrasonographic determination of ovarian follicular. Development in superovulated heifers pretreated with FSH-P at the beginning of the estrous cycle

On Day 3 of the estrous cycle (estrus = Day 0), dairy heifers were given either 10 mg i.m. FSH-P (FSH-P primed; n = 9) or a saline vehicle (saline primed; n = 9). On Day 10, all heifers were superovulated with FSH-P (total = 27.7 mg i.m.) in declining doses over 5 d. Heifers were inseminated artificially at estrus. From Day 2 until estrus, the number and size of follicles >2 mm were monitored daily by ultrasonography. The mean (+/- SEM) number of corpora lutea (CL) (6.2 +/- 1.5 vs 10.7 +/- 0.9; P<0.05) and the mean number of recovered embryos and unfertilized ova (3.6 +/- 1.7 vs 8.4 +/- 2.2; P<0.05) were lower in FSH-P-primed than in saline-primed heifers. Prior to initiation of superovulation, follicles >10 mm appeared on Days 6 to 7 in saline-primed heifers but only on Days 8 to 10 in FSH-P-primed heifers (P<0.05). Also, until Day 10, the mean number of follicles 4 to 6 mm and 7 to 10 mm was higher (P<0.05) in FSH-P-primed than in saline-primed heifers. After initiation of the superovulatory treatment (Day 10 to estrus), saline-primed heifers had a greater and faster increase in the mean number of follicles >10 mm (P<0.02) than FSH-P-primed heifers did. Depletion in the number of follicles 2 to 3 mm (P<0.001) between Day 10 and estrus and in the number of follicles 4 to 6 mm (P<0.05) between Day 12 and estrus occurred in both groups of heifers. Decreased superovulatory response and embryo recovery in FSH-P-primed heifers may have been due to the presence of large follicles (>10 mm) prior to the initiation of the superovulatory treatment which reduced the ability of small follicles to grow into larger size classes during superovulatory treatment.     

The occurrence of endotoxin in sows with coliform mastitis

The purpose of this study was to determine the role of endotoxins in the etiology of coliform mastitis /CM/ in sows under field conditions, by using the Limulus amebocyte lysate /LAL/ test for the detection of endotoxins in the blood of pigs. For this purpose, blood samples from 40 healthy sows and 46 sows with clinical signs of CM were drawn once between 24 and 72 h post partum and tested accordingly. Only one clinically healthy sow 2.5% showed the presence of endotoxins in the serum. In sows clinically affected with one or more symptoms of the CM, the bacterial toxins were detected in 15 cases /32.5%/. The results of these studies support the observation that in only a certain percentage of all CM cases the occurrence of endotoxin in blood can be shown. Sampling time in relation to the occurrence of clinical symptoms and sampling frequency may have had an influence on the detectability of circulating endotoxins. Consequently, not all cases with endotoxemia may have been identified. The usefulness of the LAL test for endotoxin detection in the blood of pigs was confirmed.     

Production of bovine identical twins via transfer of demi-embryos without zonae pellucidae

Embryos were collected nonsurgically from n?turally-cycling or superovulated donors 7 d after estrus. Forty-four morulae, early blastocysts and blastocysts classified as good to excellent were bisected using a fine glass needle to produce forty-four identical demi-embryos. The bisected demi-embryos, without zonae pellucidae, were nonsurgically transferred, either by twin or single transfer. An additional forty-eight embryos were collected from the same donors and transferred as a control. Among the twin transfers, 8 of the 13 recipients became pregnant (61.5%). Seven of them conceived twin fetuses (87%) and one a single fetus. However, only two sets of normal identical twin calves were obtained. Among the single transfers, 72.6% (45/62) of bisected embryos without zonae pellucidae resulted in pregnancy, of which 48.4% (30/62) were identical twins, and 24.2% (15/62) were singletons. Another 27.4% (17/62) of the recipients did not became pregnant. The pregnancy rate for whole embryos with zonae pellucidae was 72.9% (35/48). These data show that there was no significant difference between the pregnancy rates of bisected embryos without zonae pellucidae and whole embryos with zonae pellucidae transferred 7 d after estrus. Bisection of bovine embryos was simplified and even morula stage embryos were transferred without zonae pellucidae.     

The effects of estrous cow serum on the in vitro maturation and fertilization of the bovine follicular oocyte

The effect of serum obtained from a cow at the time of standing estrus (serum A), at ovulation (serum B), and at 24 h after ovulation (serum C) on the in vitro maturation and fertilization of bovine oocytes was examined. Of 144 (Group A), 159 (Group B), and 158 (Group C) oocytes, 77 (53.4%), 82 (51.6%) and 82 (51.9%) oocytes were characterized by expansion of cumulus cells, respectively. There was no significant difference in the effect of the three types of cow serum on the cumulus expansion (P < 0.05). Of 461 oocytes, 316 oocytes were cultured with sperm for fertilization, and 145 oocytes were cultured without sperm for evidence of parthenogenetic development. Of 56 (Group A), 56 (Group B), and 62 (Group C) oocytes with expanded cumulus cells, 19 (33.9%), 7 (12.5%), and 11 (17.7%) oocytes were cleaved, respectively, after exposed to the sperm for 24 h. There was a significant difference in the effect of the three types of cow serum on the fertilization rate (P < 0.05). A total of 145 oocytes was cultured in the absence of sperm and no evidence of parthenogenetic division was observed. The effect of the three types of serum obtained from the cow on the maturation of oocytes was not significant, but a significant difference did exist in the fertilization rate of oocytes. Cow serum obtained at the time of standing estrus had a beneficial effect on the fertilization rate of oocytes in vitro.