TDK conference 2015

The aim of our study was to determine how the presence of cavity in the corpus luteum affect the success of a prostaglandin F2α treatments on dairy farms of Eastern Hungary in a heat stress free period. The treatments were performed on a dairy farm in a Jasz-Nagykun-Szolnok county, where 600 cows takes part in the production. The study was carried out from autumn of 2013 to spring of 2014.

All animals were given 500 µg intramuscular injection of synthetic cloprostenol. 3 days after the prostaglandin treatment rectal palpation was performed and in cases of diagnosed oestrus the animals were inseminated. Oestrus observation was carried out 2-7 after the treatment and the animals in oestrus were also inseminated after rectal palpation. Pregnancy test followed the artificial insemination in 28-42 days. These tests were performed with mobile ultasound device (Easy-Scan BCF Technologies, Great Britain).

Altogether we treated 305 cows, 213 was inseminated within 2-7 days after treatment (69.8%). The efficiacy of the treatment (resulted in artificial insemination) was 84,2% in animals with compact textured corpus luteum, in contrast with cows who have cavitary corpus luteum, 68,8% (p>0,1). Cows what have compact textured corpus luteum got pregnant in 34,1% after the treatment whereas the cows with cavitary corpus luteum get pregnant in 32,8% (0,1>p).

33,7% of the cows, who had only one corpus luteum became pregnant, whereas 50% of those who had two corpora lutea (p>0.1). 34,1% of the animals with one compact textured corpus luteum, meanwhile 32,8% of the cows who had one cavitary corpus luteum became pregnant (p>0,1). The pregnancy rate with one compact structured corpus luteum was 52% , while in cases of two cavitary corpora lutea was 40 % (p>0,1).

We also investigated how the size of the cavity can influence the pregnancy rates. In case of small cavity (cavity smaller than 50 % of the total diameter) in the corpus luteum the proportion was 32,5%, but in case of big cavity in the corpus luteum it was 33,3% (p>0,1).

Based on the results, there was not any significant difference between the animals with cavitary corpus luteum or compact txtured corpus luteum during the PGF2α treatment, neither in inducing estrus, nor in the result of artificial insemination after the cloprostenol treatment.