Relationship between vaginal mucus conductivity and time of ovulation in weaned sows

This study investigated whether changes in the vaginal electrical resistance (VER) of vaginal mucus of weaned sows during the first 7 d post-weaning are associated with time of ovulation. Time of ovulation was determined by ovarian ultrasound carried out from 91 to 146 h after weaning and at different seasons. Vaginal electrical resistance was measured at 20, 44, 68, 91, 96, 102, 115, 120, 126, 140, 146, and 164 h post-weaning and was found to decrease between 120 h and 31 h before ovulation and then increase until 40 to 50 h after ovulation. Duration and timing of the nadir was affected by the season (P < 0.01). Estrus was observed from day 4 after the lowest VER values. Ovulation occurred between late day 5 and late day 6, while VER values were still increasing. Ovulation was earlier in lower parity sows (P < 0.001). Compared to 0 h (ovulation time), VER was significantly lower from 50 to 5 h before ovulation in autumn and from 40 to 21 h in winter, but such differences were not seen in spring. Lowest VER value was not correlated with time of ovulation. It was concluded that VER increases before ovulation and, although this increase is influenced by the season, it cannot be used to accurately predict ovulation in weaned sows.     

Investigation of vaginal mucus parameters: Development of models for staging the oestrous cycle of the Bunaji cow

Changes in some vaginal mucus parameters were studied in order to generate predictive models capable of enhancing oestrous cycle staging, using equal groups (unsynchronized-USC [no treatment] and synchronized-SC [Synchromate^® i/m on d0, d11]) of Bunaji cows (n = 48) aged 3–4 years. Vaginal mucus was collected (starting d11 in SC) daily over 26 days using standard procedures. Physical (viscosity, elasticity, density, resistivity) and biochemical (pH, glucose, cholesterol, total protein, calcium, magnesium, sodium, potassium) parameters were evaluated using standard procedures. Data were analysed using chi-square and multinomial logit regression modelling. Models generated using oestrus as reference categories were ascertained for accuracies. Chi-square values for viscosity, elasticity and density were significant (p < .01) in USC and SC across stages of the cycle. Results for USC showed that pH and cholesterol were predictive (p < .01) for pro-oestrus, metoestrus and dioestrus, while total protein was predictive (p < .01) for dioestrus only. Similarly, magnesium was predictive (p < .05) for pro-oestrus. For SC, pH, magnesium and cholesterol were predictive (p < .01) for pro-oestrus, metoestrus and dioestrus, while total protein was predictive (p < .01) for pro-oestrus and dioestrus. Potassium and total protein were also predictive for metoestrus at 10% and 5% significance levels, respectively. Though findings suggest the usefulness of magnesium in staging the oestrous cycle only in synchronized cows, pH, total protein and cholesterol appeared to be the more important vaginal mucus parameters in Bunaji cows, regardless synchronization. Furthermore, the models developed showed high accuracy levels for staging the oestrous cycle in USC (100%) and SC (89%).     

Post-partum oestrous behaviour in sows is not associated with ovulation

Sows occasionally show oestrous behaviour within 5 days of farrowing; this is termed post-partum oestrus (PPO). This study investigated the incidence and possible causes of PPO on nine Dutch farms. Lactation records (n=1374) were used, backfat thickness was measured (n=25), and ovarian condition was assessed by transrectal ultrasonography. The incidence of' PPO ranged from 0% to 62% on the different farms. On average, PPO started 59 hours after farrowing and lasted for 55 hours. Sows with PPO were younger than sows without PPO (parity 3.8 +/- 0.2 vs 4.4 +/- 0.1, respectively; P < 0. 05) and had more backfat than sows without PPO (21.3 +/- 1.2 vs 17.9 +/- 1.2 mm, respectively; P < 0.10). Occasionally, some follicle growth was observed in sows with PPO, but ovulation did not occur. PPO did not affect the weaning-to-mating interval or piglet mortality during lactation.     

Changes in electrical resistance of the vaginal mucosa in prostaglandin-treated cows

Ten Hereford x Friesian cows each received 1 mg fenprostalene by a single subcutaneous injection between days 5 and 16 of their ovarian cycles and the treatment was repeated 17 days later. The cows' ovarian cycles were monitored by daily plasma progesterone measurements, and the electrical resistance of their vaginal mucosae was also measured daily, with a Wallsmeta. Luteolysis occurred after 13 of the 20 injections of fenprostalene, and vaginal resistance measurements corresponded to changes in progesterone concentrations in 14 of the 20 potential luteolytic periods. Vaginal resistance measurements decreased in three cases where progesterone concentrations did not decrease (false positive results) and failed to decrease in three cases where progesterone concentrations did decrease (false negative results).     

丹系母猪断奶后发情和排卵规律的研究

母猪适时配种是提高受胎率的关键措施之一,而决定配种时间的主要依据是母猪排卵时间。本研究采用B超探测技术对56头不同胎龄的丹系高产母猪发情后的排卵规律进行观测研究。结果发现,母猪断奶后发情至排卵间隔平均为(29.28±8.14)h,排卵持续时间平均是(14.64±4.07)h;母猪断奶至发情间隔为4 d时,母猪发情至排卵间隔和排卵持续时间与其他组差异均显著(P0.05);当断奶至发情天数从2 d增加到5 d,发情至排卵间隔平均减少4.78 h,排卵持续时间平均减少2.39 h;哺乳期小于25 d的母猪断奶到发情间隔及排卵间隔与其他两组母猪均差异显著(P0.05);不同哺乳期的母猪排卵持续时间差异不显著(P0.05);胎次对母猪发情排卵时间存在一定的影响,高胎次母猪比低胎次母猪断奶后发情较迟,排卵持续时间也较长。     

The vaginal mucus agglutination test in the diagnosis of bovine brucellosis

Of 1140 vaginal mucus agglutination tests (VMAT) on specimens obtained in 1971-72 from 663 dairy cows in seven herds infected with brucellosis, 97 were positive. When the VMAT was positive one or more serological tests were also positive. Of the 97 corresponding serum agglutination tests 80 sera had titres of more than 533 international units. Only 69.8 per cent of VMAT from serologically positive cows were positive. No evidence was found of non-specific agglutinins in vaginal mucus and positive VMAT reactions appeared to be specific for field infection. Three cows showed evidence of local agglutinins in the vagina. Hence herd testing by VMAT has no advantage over tests of blood serum but the test could be an aid in establishing whether individual cattle are infected.     

Separation of mounting-inducing pheromones of vaginal mucus from estrual heifers

There is evidence that mucus of the female bovine genital tract contains pheromones that induce physiological and behavioral responses in other animals. To study these pheromones, vaginal mucus was collected from heifers either at estrus or during diestrus. The mucus was then applied to the hindquarters of the same animal during diestrus or to the hindquarters of herdmates during diestrus. The behaviors of the treated animal and its herdmates were then observed. To attempt to isolate the mounting-inducing substance, mucus was dialyzed or separated on ion-exchange resins. Diestrous heifers to which their own estrual mucus has been applied were nearly always mounted by herdmates (P less than .01). But, heifers to which another's estrous mucus had been applied were not mounted. This suggests that vaginal mucus contains not only estrus-related pheromones, but also individual distinctive odors. The dialyzable fraction of vaginal mucus and the neutral fraction, prepared by ion-exchange chromatography of the dialyzable solution of vaginal mucus, had a mounting-inducing activity on the herdmates, as did the application of an animal's own vaginal mucus. These findings suggest that mounting-inducing pheromones are relatively low molecular weight, neutral substances.     

Changes in lipid levels in the blood of pregnant sows]

Variations of plasma volume (PV) and variations of triglyceride, cholesterol, total lipid, beta-lipoprotein and phospholipid concentrations in the blood plasma were investigated in trials with ten sows, crossbreds of the White Thoroughbred and Landrace breeds, at the age of 2-3 years, kept on a defined diet; the trials were performed before the sows became pregnant and during their pregnancy (days 1-40, 41-60, 61-80, 81-100 and 101-120). The PV in nonpregnant sows is 9.8 +/- 0.33 1. Following a decrease to the values of 7.8 +/- 0.33 l (p less than 0.01) in the first 40 days of pregnancy the plasma volume increases in the successive periods and it makes 15.4 +/- 0.19 l at the end of pregnancy (p less than 0.001). Total lipaemia decreases during pregnancy from 2.80 +/- 0.054 in nonpregnant sows to 2.49 +/- 0.245 g per 1 in sows at the end of pregnancy. Cholesterol concentrations in the blood plasma also decrease from 2.48 +/- 0.53 in nonpregnant ones to 1.88 +/- 0.173 mmol per 1 (p less than 0.001) in sows at the end of pregnancy, beta-lipoprotein concentrations from 3.95 +/- 1.134 in nonpregnant ones to 3.47 +/- 0.199 g per l in sows on days of pregnancy 81-100 (p less than 0.05), phospholipid concentrations in the first 60 days of pregnancy from 1.62 +/- 0.079 before insemination to 1.29 +/- 0.05 mmol per l in sows of 41-60 day pregnancy.(ABSTRACT TRUNCATED AT 250 WORDS)     

Changes in the dimensions of the uterus of the Beagle bitch during the oestrous cycle

Results are presented of the changes in the dimensions of the horns of the uterus during the oestrous cycle in the Beagle bitch. The data, based on seventy-three observations in fifty-three animals, indicate that from the onset of oestrus the width and thickness of the uterus increase and reach peak values 7–9 weeks later.
Résumé. On présente les résultats des changements de dimension des prolongements de l'utérus, rencontrés pendant l'oestre d'une chienne Beagle. Les données, basées sur soixante-treize observations de cinquante-trois animaux, indiquent que dès le commencement du cycle la largeur et l'épaisseur de l'utérus s'accroissent et atteignent leurs valeurs maximales sept à neuf semaines plus tard.
Zusammenfassung. Es werden die Ergebnisse der Untersuchung von Dimensionsveränderungen der Uterushörner während des östrischen Zyklus bei der Beaglehündin angegeben. Die Daten von 73 Beobachtungen an 53 Tieren lassen erkennen, dass vom Beginn des Östrus die Breite und Dicke des Uterus zunehmen und 7 bis 9 Wochen später Maxima erreichen.