Premature elevation of progesterone shortens duration of ovulation in PMSG/hCG-treated prepuberal gilts

A surge of LH during the follicular phase triggers multiple pathways, including progesterone and prostaglandin synthesis before culminating in ovulation. Progesterone has been shown to be involved in the ovulatory process in many species. In prepuberal gilts treated with PMSG/hCG the follicular progesterone level has been shown to increase sharply before ovulation. This study was conducted to investigate whether premature elevation of progesterone can accelerate the ovulatory process in Large White PMSG/hCG-treated prepuberal gilts. Fifty-four Large White gilts were treated with 1000 IU, im PMSG to stimulate follicular growth, followed 72 h later by 500 IU, im hCG to induce ovulation. Gilts in the treatment group (n=27) were given progesterone intermuscularly at 24 and 36 h after hCG. Ovaries were exteriorized to observe ovulation points during laparotomy under general anesthesia at 38 to 50 h after hCG. Ovulation in both groups commenced by 40.05 h after hCG and was completed by 47.71 h in the control group and by 42.87 h after hCG in the treated group. Progesterone shortened (P < 0.01) ovulation time by 4.84 h and the time required (P < 0.01) for the median proportion of follicles to ovulate (40.7 vs 43.5 h after hCG). Progesterone also increased (P < 0.01) the plasma progesterone concentration without altering follicular progesterone concentration

Efficiency of Intravulval Lip Route of Prostaglandin F2a Administration on Estrus Synchron

Estrus was synchronized in dairy cattle using the synthetic prostaglandin F2a (PG) analog Estnunate (Coopers Animal Health Ltd., Berkhamsed, England. UK; 250 ug/ml of cloprostenol). PG was administered by two routes at two different doses, 500 ug by im route (control) and 125 pg by intravulval lip (ivu) route (treatment). All animals were bred by artificial insemination (AI) to detected estrus using the am-pm breeding rule (BR). First service conception rate (FSCR) for all dairy cows and heifers was 70% for the control and 54% for the treatment groups (P&gt;0.05). The FSCR was also not different (P&gt;0.05) between Holstein (HOL) and Australian Milking Zebu (AMZ) breeds (HOL 52% and AMZ 78%). Moreover, all the animals in this study were confirmed pregnant by the end of the breeding season. In conclusion, dairy cows and heifers can be successfully synchronized using only 125 pg of cloprostenol without impairing fertility. This dose corresponds to only one fourth of the recommended dose of 500 pg of cloprostenol by the manufacturer. 

Efficiency of Intravulval Lip Route of Prostaglandin F2a Administration on Estrus Synchron

Estrus was synchronized in dairy cattle using the synthetic prostaglandin F2a (PG) analog Estnunate (Coopers Animal Health Ltd., Berkhamsed, England. UK; 250 ug/ml of cloprostenol). PG was administered by two routes at two different doses, 500 ug by im route (control) and 125 pg by intravulval lip (ivu) route (treatment). All animals were bred by artificial insemination (AI) to detected estrus using the am-pm breeding rule (BR). First service conception rate (FSCR) for all dairy cows and heifers was 70% for the control and 54% for the treatment groups (P>0.05). The FSCR was also not different (P>0.05) between Holstein (HOL) and Australian Milking Zebu (AMZ) breeds (HOL 52% and AMZ 78%). Moreover, all the animals in this study were confirmed pregnant by the end of the breeding season. In conclusion, dairy cows and heifers can be successfully synchronized using only 125 pg of cloprostenol without impairing fertility. This dose corresponds to only one fourth of the recommended dose of 500 pg of cloprostenol by the manufacturer

Performance of Lactating Dairy Cows Fed Dried Sardines

To utilize locally available feed resources with livestock production in hot climates, dried sardines were incorporated into diets for lactating dairy cows. Fourteen Holstein and 13 Australian Milk Zebu multiparous cows were used in a 70-day continuous feeding experiment. lsonitrogenous and isoenergetic diets containing either soybean meal or dried sardines (supplied 40% of dietary crude protein) were fed ad - libitum. Comparisons between diets were made during the 7-week experimental period. The experiment was conducted as a 2 x 2 factorial arrangement of treatment, with diet and breed as main factors. Ruminal pH, ammonia N, total and individual volatile fatty acids concentrations were not altered by the feeding of dried sardines. Intakes of dry matter, energy, crude protein, and acid detergent fiber were lower (P0.05) in Holstein cows fed dried sardines than those fed the control diet (16.2 vs 15.1 kg/d). Feeding of dried sardines did not affect milk composition and compositional yields. Milk production was higher (P<0.01) in Holstein than Australian Milk Zebu cows. Effect of diet and breed interaction on milk production was significant (P<0.01 ). Potential of feeding marine proteins may be higher for higher milk producers (Holstein) than lower producers (Australian Milk Zebu). Reproduction parameters, body condition scores, and heat-stress associated parameters were not affected by the feeding of dried sardines. This study suggests that dried sardines could be incorporated into diets of lactating dairy cows without affecting milk production

Comparing the values of progesterone in the blood of bitches as measured with a chemiluminescence immunoassay and a radioimmunoassay

Please read abstract in the article.The National Research Foundation funded the Coat‐A‐Count radioimmunoassay kits and the laboratory fees for the determination of values of progesterone. Siemens donated the Immulite kits.http://wileyonlinelibrary.com/journal/rda2019-10-01hj2018Production Animal Studie