Plasma urea nitrogen in relation to pregnancy rate in dairy sheep

in Animal reproduction science (2011), 124(1-2), 69-72

The aim of this field study was to investigate the relationship of plasma urea nitrogen (PUN) with the pregnancy rate in lactating AwassixMerino ewes. One hundred and eighty-five AwassixMerino ewes were ... [more ▼]

The aim of this field study was to investigate the relationship of plasma urea nitrogen (PUN) with the pregnancy rate in lactating AwassixMerino ewes. One hundred and eighty-five AwassixMerino ewes were used in the present study. Ewes were fed a diet containing 17.4% crude protein and were milked twice a day by the milking machine. The ewes were synchronized for estrus by insertion of intravaginal sponges containing 30mg flurogestone acetate for 14 days. At the time of sponge removal each ewe was administered eCG (600IU). All ewes were inseminated twice with fresh semen into the external os of the cervix at 48 and 56h after sponge removal. The day of insemination was considered as Day 0 for calculating the gestational period. Blood samples were collected from each ewe at Days 0, 18 for measurement of PUN concentrations and at Day 22 after AI for measurement of pregnancy-associated glycoprotein (PAG) by radioimmunoassay (RIA). Thirty-eight ewes (20.5%) were confirmed pregnant by PAG-RIA test at Day 22 and by ultrasonography at Day 80. The mean (+/-S.D.) concentration of PUN in all ewes at Day 0 was 12.7+/-4.6mmol/L. There were non-significant differences in the level of PUN between pregnant and non-pregnant ewes at Days 0 (12.2+/-4.2mmol/L vs. 12.8+/-4.7mmol/L, respectively) and 18 (9.6+/-2.9mmol/L vs. 10.4+/-4.0mmol/L, respectively) after AI. Mean PUN concentrations decreased significantly from Day 0 to Day 18 after AI in both pregnant and non-pregnant ewes. By using logistic regression analysis, there was no effect of PUN concentrations on the probability of pregnancy occurrence in the studied ewes (odds ratio: 0.97; 95% confidence interval: 0.9-1.05; P=0.45). In conclusion, there was no evidence of a relationship between PUN concentration and pregnancy rate for lactating AwassixMerino ewes in the present study because of low pregnancy rate observed. [less ▲]

Effect of the type and number of prostaglandin treatments on corpus luteum, the largest follicle and progesterone concentration in dairy cows

in Reproduction in Domestic Animals (2005), 40(5), 436-442

Lactating dairy cows (n = 72) with a mature corpus luteum (CL) (diameter of >= 17 mm) determined by ultrasonography and having a follicle with a diameter of >= 10 min were randomly assigned to four groups ... [more ▼]

Lactating dairy cows (n = 72) with a mature corpus luteum (CL) (diameter of >= 17 mm) determined by ultrasonography and having a follicle with a diameter of >= 10 min were randomly assigned to four groups. Cows were treated with cloprostenol i.m. once or twice, or with dinoprost i.m. once or twice with an 8-h interval. The ovaries of each cow were scanned daily by transrectal ultrasonography to measure the changes in the areas of CL and the largest follicle and to determine the occurrence of ovulation. Oestrus was verified twice daily. In addition, blood sample was withdrawn from each cow daily for measuring progesterone (P4) concentrations. Significant decreases in the percentage changes relative to areas of CL and P4 concentrations or increases in the percentage changes in the area of the largest follicle on day 0 were detected in each group during the experiment. However, the type of the drug and the number of the treatments had no significant effect on those parameters. Cows ovulated with or without showing oestrus (group A) and cows exhibiting no oestrus and ovulation (group 13) were also evaluated. In contrast to the mean area of the CL and the mean concentration of P4 on day 0, the mean area of the largest follicles between, the two groups on day 0 differed significantly Significant decreases in the percentage changes relative to the area of the CL and P4 concentration or increases in the percentage changes relative to the area of the largest follicle during the experiment were detected in both groups; however, there were no group differences. Treatment of dairy cows with two injections of prostaglandins (cloprostenol or dinoprost) at an 8-h interval resulted in more cows being, observed in oestrus within 5 days after treatment and having significantly higher pregnancy rate than those treated with a single prostaglandin injection. [less ▲]

Effect of plasma urea-N concentration on fertility in a Holstein-Friesian dairy herd

in Magyar Allatorvosok Lapja = Hungarian Veterinary Journal (2003), 125(8), 458-464

The objectives of this study were to relate the concentrations of plasma urea nitrogen (UN) to pregnancy rate in dairy cows. The cows were grouped, according to their production level and feed rations ... [more ▼]

The objectives of this study were to relate the concentrations of plasma urea nitrogen (UN) to pregnancy rate in dairy cows. The cows were grouped, according to their production level and feed rations according to the NRC recommendations for essential nutrients, Holstein-Friesian dairy cows (n=103), randomly selected, were inseminated between Days 39 and 410 after calving. The cows were separated into two groups, where Group 1, was treated with GnRH i.m. injection on Day 12 after At. Group 2, was not treated and served as a control group. Heparinized blood samples were taken from the tall vein, immediately taken after artificial insemination (Day 0) and subsequently on Days 12, 21, 32 and 55 after Al, respectively. Diagnosis of pregnancy and late embryonic mortality was made by ultrasonography and the measurement of pregnancy proteins (PAG) between Days 32 and 55 after Al. Changes in plasma UN concentrations were studied using multivariate repeated ANOVA procedures. Three cows in each group were insemineted in the lutheal phase therefore their data were not used in the calculation. There were no significant differences between the UN concentrations of the pregnant and non-pregnant cows within the groups. However, the time of sampling had a significant effect on the UN concentrations in both the control and the treated groups. The UN concentrations, in pregnant and non pregnant cows of both groups, were significantly decreasing from Day 0 to Day 32. Concentrations of UN (on Day 0) less than 5,8 mmol/l were associated with increased pregnancy rates (53.6%). The pregnancy rates for cows with UN concentrations within the ranges of 5,7-6,75 mmol/l and 6,76-7,82 mmol/l were 47.8% and 46.7%, respectively. The rate of late embryonic mortality was similar in the two groups (treated group: n=2, control group: n=3). [less ▲]

A juhok korai vemhességének megállaoítása progeszeteron és a vemhességi fehérje meghatároásával

in Proceedings: 12th Magyar Buiatrikus Kongresszus (2001)