Reproductive activity of gilts with prolonged preinsemination anoestrus after hormonal treatment

Abstract

Due to the prolonged preinsemination anoestrus (the sings of oestrus were not found even after eight months of age) 25 to 40% of gilts are culled on the farms in Vojvodina. The question is if those gilts did not reach puberty at all or if it was the result of an inadequate technology in oestrus detection. Concerning this issue, a morphological examination of the genital organs of 175 gilts, in which oestrus was not detected during the first 8 to 9 months of age, was carried out. The average age of these gilts was, at sacrifice, 267 days (242 to 278 days). In further research, the treatment of delayed puberty gilts and control gilts was carried out with hormone preparations from the progestin group (Regumate, Altrenogest) or placental gonadotropin (PMSG - 'Folligon'). Based on examination of the gilts' genital organs, in which oestrus was not detected even after 8 months of age, it was established that 38.9% of those gilts did not reach sexual maturity at all, i.e. did not have cyclic ovarian activity. With the other 61.1% of the examined gilts, the puberty ovarian cyclicity was established, as their ovaries had the functional structures (preovulatary follicles, corpora hemorrhagica, corpora lutea and corpora albicantia). Thus, one oestrus cycle was reached by 57.9% while two oestrous cycles were reached by 42.1% out of the total number of sexually mature gilts. A high degree of oestrous reaction (80%), a high farrowing rate (87.5%) and a satisfactory average number of live-born piglets per litter were established in the delayed puberty gilts treated with the Regumate preparation. The obtained results distinctly show that a great number of gilts reached the puberty cyclic ovarian activity while the absence of oestrus detection was the result of inadequate technology in oestrus detection on farms.