Prostaglandin-induced abortion in swine: endocrine changes and influence on subsequent reproductive activity

Gilts were treated during midgestation with prostaglandin (PG) F to study the efficacy of different treatment regimens on induction of abortion and to determine the adverse consequences of PGF-induced abortion in swine. In study 1, pregnant purebred Duroc gilts (60 to 90 days of gestation) were given (IM) 500 micrograms of cloprostenol (n = 12), 20 mg of dinoprost tromethamine (n = 11), or 10 mg of dinoprost tromethamine repeated 12 hours later by an additional 10 mg of dinoprost tromethamine (n = 11). The percentage of gilts that aborted and percentage of aborted gilts that returned to estrus for each treatment group were as follows: cloprostenol, 91.7% and 100%, respectively; 20 mg of dinoprost tromethamine, 36.4% and 25.0%, respectively; and 10 + 10 mg of dinoprost tromethamine, 100% and 90.9%, respectively. Treatment with cloprostenol and with 10 + 10 mg of dinoprost tromethamine caused more gilts to abort (P less than 0.01) than did treatment with 20 mg of dinoprost tromethamine. Gilts that did not abort were given a second treatment with 10 + 10 mg of dinoprost tromethamine. When the abortions by gilts initially treated with 500 micrograms of cloprostenol or 10 + 10 mg of dinoprost tromethamine were combined with those re-treated with 10 + 10 mg of dinoprost tromethamine, 32 of 33 (97.0%) gilts aborted, and 30 of the 32 (93.8%) aborted gilts returned to estrus.(ABSTRACT TRUNCATED AT 250 WORDS)     

Nematode antigens in protection, diagnosis and pathology

A thorough study of parasite antigens is a prerequisite for control programmes based on protection by vaccination, accurate serodiagnosis and perhaps immune modulation to diminish pathological sequelae. Stage specific surface secreted and somatic antigens may be of particular value in proceeding towards these goals. The design of vaccines is most appropriately focused on surface antigens. With respect to pathology, certain antigens must stimulate humoral and, or cellular immune responses which are responsible for the undesirable immunopathologic consequences of the disease. The ultimate objective, therefore, is identification of those particular antigens followed by appropriate down regulation of the immune system in order to delete such potentially harmful immunological reactions. The relevant illustration presented in this context is an interesting correlation between one particular clinical condition of onchocerciasis ("sowda") and the serological response, defined both in terms of the parasite antigen and an immunoglobulin class restricted antibody response. Current parasitological methods of diagnosis consistently underestimate parasite prevalence. Failure to detect low level patent infections incurs the risk of having a reservoir capable of perpetuating infections. There is, then, an urgent requirement for accurate serodiagnosis, to be used in association with, and for the evaluation of, drug treatment and vector elimination in parasite control programmes. Given the high sensitivity of current immunoassay technology, the only bar to establishing the necessary immunological tests is the choice of suitably specific antibody-antigen systems. Once these are identified, a combination of recombinant nucleic acid biochemistry and hybridoma technology should provide the necessary reagents for inexpensive, robust and specific diagnostic tests. In addition, it may not be many years before the ubiquitous RIA and ELISA technology gives way to the newly developing biosensor systems. Finally, given the sensitivity and specificity of today's nucleic acid hybridization techniques, we may soon expect to see specific identification of infective larvae in their vectors of this, a cloned DNA probe specific for Onchocerca volvulus, and with potential for the detection of infective larvae in blackflies is described.     

Pregnancy diagnosis in Swine: a comparison of two ultrasound instruments

This investigation was designed to assess the sensitivity, specificity and positive predictive values of amplitude-depth and Doppler pregnancy detectors when utilized for pregnancy diagnosis of mated sows. Mated sows (n = 38) were tested daily from 15 to 45 days after mating for pregnancy with the ultrasound instruments. The same procedure was performed with nonmated sows (n = 10) 15 to 45 days after estrus. Both instruments were unreliable for pregnancy diagnosis between 15 and 22 days after mating. Between 23 and 45 days after mating the Doppler pregnancy detector was more specific and had greater positive predictive values. In contrast the amplitude-depth pregnancy detector was more sensitive during the same time interval.

Serum estrone sulphate concentrations were determined in samples collected between 27 and 30 days after mating or estrus, as an alternate method of pregnancy diagnosis. Serum estrone sulphate concentrations were always equal to or greater than 0.5 ng/mL in the pregnant sows, while in the nonmated sows estrone sulphate concentrations were never more than 0.5 ng/mL serum.

     

Autumn abortions in sows

This report describes the diagnosis and management of autumn abortions in a commercial swine herd in Ontario. A consistent pattern of abortions in the fall (and to a lesser extent, winter and spring) months was established from the herd records of 1980 to 1982. The percent abortions (of all farrowings) was 2.2, 3.7 and 4.3 for the years 1980, 1981 and 1982 respectively. Since laboratory examinations did not identify a specific pathogen, the management and the environment were investigated. In December 1982, supplemental heat was provided in the gestation barn to counteract heat losses at the level of the pregnant sows. The percent abortions was reduced to 0.4 over the next 12 months.     

Seasonal infertility in large pig production units in an Eastern-European climate

OBJECTIVES: To demonstrate the occurrence of seasonal infertility of sows in large production units in Eastern Europe. DESIGN: Weaners in this trial originated from a 1000 sow Croatian herd that weaned piglets at 14 or 28 days of age. The production records of 15 indoor (795 to 1849 sows per herd) pig farms with identical feeding, similar genetics and health status, were evaluated. The reproductive performance of sows when the average daily (9 am to 4 pm) temperature was more than 35 degrees C, was compared with the weeks when it was lower than 30 degrees C. RESULTS: During periods of high temperature (> 35 degrees C) sows had significantly (P < or = 0.05) longer weaning to service intervals and more regular returns to service (P < or = 0.05) compared to weeks of less than 30 degrees C daily temperature in the same summer season. Irregular returns to service were low and showed no significant differences during the same time periods. Farrowing rates and total litter sizes were lower (P < or = 0.05) for periods of higher than 35 degrees C daily temperature compared to weeks of less than 30 degrees C daily temperature in the same summer season. CONCLUSION: When daily temperatures are higher than 35 degrees C, reproductive performance is likely to be depressed in large pig production units.     

Short communication: effects of a gonadotropin application on seasonal subfertility in pigs

In this study the reproductive performance of weaned sows in a large production unit was evaluated during periods of high (> 35 degrees C) summer temperatures. Only weaned sows of parity 2-6 (a total of n = 3386) were evaluated in two groups in 13 replicates: Group 1 (n = 1694): The sows were treated subcutaneously with 400 I.U. of Gonadotropinum sericum (pregnant mare serum gonadotropin, PMSG [eCG]) and 200 I.U. of Gonadotropinum chorionicum (human choriongonadotropin, HCG [hCG]) on the day of weaning. Group 2: (n=1692). The sows received subcutaneously 4 ml of physiological NaCl solution on the day of weaning. Weaning to service intervals, regular and irregular returns to service, farrowing rates, and subsequent litter sizes were evaluated. Control sows had longer (P < 0.01) weaning to service intervals and more (P < 0.01) regular returns to service during hot weather periods compared with the gonadotropin treated sows. Irregular returns to service were low and showed no significant differences between the treated and non-treated sows (1.4+/-0.3 % vs. 1.5+/-0.4 %). Farrowing rates and litter sizes were significantly (P < 0.01) better in the treated compared with the non-treated sows.     

Failure of a single postpartum prostaglandin treatment to improve the reproductive performance of dairy cows

A study was conducted to evaluate the effects of postpartum prostaglandin treatment on reproduction in 3 seasonal calving dairy herds. Recently calved lactating dairy cows were paired on herd, age, calving date and previous production index. One cow in each of the 196 pairs received a single intramuscular injection of 25 mg of the prostaglandin analogue, dinoprost, between 14 and 28 days after calving. Subsequent reproduction was monitored. Within each herd and overall, there was no significant effect of treatment on the intervals from calving to first service, mating start date to first service, calving to conception, mating start date to conception and first service to conception. Treatment also had no significant effect on 21-day submission and pregnancy rates, on the proportion of each group not pregnant at the end of mating, and on first service pregnancy rates. Responses to treatment did not vary between cows calving within 50 days of mating start date and earlier calving cows or between cows aged less than 5 years and older cows.     

The influence of ovariectomy on luteinizing hormone concentrations in anestrous and cyclic sows

In an effort to determine whether anestrus in swine is due to aberrant ovarian feedback control of gonadotropin release, this study contrasted the influence of ovariectomy on LH concentrations in serum of anestrous sows and in sows that returned to estrus following weaning. Blood samples were collected at 6-h intervals from 7 d prior to until 4 d after ovariectomy of 22 anestrous and 24 cyclic sows. Blood samples also were collected at 15-min intervals for 8 h at 2 d prior to and 2 d after ovariectomy. Sampling at 6-h intervals continued until 12 d after ovariectomy and additional 8-h windows of 15-min samples were taken at 7 and 12 d after ovariectomy of seven anestrous and nine diestrous sows. Mean LH concentrations and LH pulse frequencies were greater (P less than .05) 2 d after ovariectomy than 2 d prior to ovariectomy in both anestrous and diestrous sows. Mean pulse amplitude had increased by 2 d after ovariectomy in anestrous sows but did not change in cyclic sows. Baselines as determined from the mean of all LH measurements excluding pulses, remained the same in both anestrous and diestrous sows at 2 d after ovariectomy. Pulse frequency, pulse amplitude, and mean LH concentration were greater (P less than .05) in both anestrous and diestrous sows at 7 and 12 d after ovariectomy than at 2 d prior to and 2 d after ovariectomy. Pulse amplitude on d 7 and 12 after ovariectomy decreased (P less than .05) in both anestrous and diestrous sows relative to those observed at earlier times.(ABSTRACT TRUNCATED AT 250 WORDS)     

Expression and Localization of Vascular Endothelial Growth Factor and its Receptors in the Corpus Luteum During Oestrous Cycle in Water Buffaloes (Bubalus bubalis)

The aim of this study was to document the expression and localization of VEGF system comprising of VEGF isoforms (VEGF 120, VEGF 164 and VEGF 188) and their receptors (VEGFR1 and VEGFR2) in buffalo corpus luteum (CL) obtained from different stages of the oestrous cycle. Real‐time RT‐PCR (qPCR), Western blot and immunohistochemistry were applied to investigate mRNA expression, protein expression and localization of examined factors. In general, all the components of VEGF system (the VEGF isoforms and their receptors) were found in the water buffalo CL during the oestrous cycle. The mRNA as well as protein expression of VEGF system was highest during the early and mid‐luteal phase, which later steadily decreased (p < 0.05) after day 10 to reach the lowest level in regressed CL. As demonstrated by immunohistochemistry, VEGF protein was localized predominantly in luteal cells; however, VEGFR1 and VEGFR2 were localized in luteal cells as well as in endothelial cells. In conclusion, the dynamics of expression and localization of VEGF system in buffalo corpora lutea during the luteal phase were demonstrated in this study, indicating the possible role of VEGF system in the regulation of luteal angiogenesis and proliferation of luteal as well as endothelial cells through their non‐angiogenic function.