An experiment was conducted to investigate the effects of hormonal synchronization of ovulation on progesterone concentrations in milk and blood serum and on reproductive performance. Sixty Holstein-Friesian cows averaging 8000 L over 305 days of lactation were divided into 2 groups of 30 animals. One-factor ANOVA and a t-test of progesterone concentrations in venous serum and milk revealed that the lowest concentrations of progesterone in milk (Ovsynch 5.8 ± 1.0 ng/mL; control 4.5 ± 0.6 ng/mL) and blood serum (Ovsynch 1.3 ± 0.9 ng/mL; control 1.4 ± 0.5 ng/mL) in both groups were found on the day of estrus or artificial insemination (AI) (both P < 0.05). Increases in the concentrations of progesterone in milk (Ovsynch 17.6 ± 4.3 ng/mL; control 10.5 ± 1.9 ng/mL) and blood serum (Ovsynch 3.6 ± 1.1 ng/mL; control 4.0 ± 1.0 ng/mL) were observed on day 7 after AI (both P < 0.05). Concentrations of progesterone in milk and blood serum in nonpregnant cows were reduced on day 21 after AI. Assessment of reproductive performance revealed that the application of treatment shortened the duration of the service period (Ovsynch 76 days; control 83 days) and the calving interval (Ovsynch 376 days; control 382 days).
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
The reproductive performance of gilts significantly affects the number of annually produced piglets per sow. The paper presents the results of an analysis of the reproductive performance of gilts on a big pig farm in Vojvodina (Republic of Serbia), with a capacity of around 5,500 sows. Out of the total of 19,000 female piglets selected for reproduction, insemination, aged 210 days, a total of 5,420 (28.5%) gilts are prepared, and 70% of these are inseminated. A total of 29.3% gilts are culled for reproduction because of longterm pre insemination anestria (estrus was not established until the age of 9 months). It is believed that the basic reason for the occurrence of long-term anestrias is the inadequate technology for detecting estrus on the farm (once every 24 hours, without direct contact between the test boar and the gilts). As a consequence, there are significant economic losses in piglet production on the examined farm
Modern intensive pig production demands an increasing number of insemination doses per ejaculate of genetically superior boars. In order to achieve such a result the possibility of producing insemination doses in both reduced volume and spermatozoa count without decreasing the fertility of sows is studied. In this trial we studied the effect of insemination with reduced volumes of semen (50 mL) and varied spermatozoa count (4, 2 or 1x109). Insemination was performed by the classical (intracervical) or by the new (intrauterine) techniques and the basic fertility parameters (farrowing % and litter size) were measured. The farrowing value decreased with decreasing spermatozoa numbers after intracervical and intrauterine insemination. However, the farrowing value, regardless of spermatozoa numbers, was significantly higher after intrauterine insemination (83.3%, 76.7%, 66.7%) compared to the classical intracervical insemination (73.3%, 66.7% and 50%). Litters size did not vary significantly depending on the applied insemination procedure or spermatozoa number. These results indicate that application of the new intrauterine insemination procedure enables the use of doses with a smaller volume and spermatozoa number, at the same time obtaining a satisfactory farrowing and litter size. This opens the possibility of obtaining a significantly higher number of doses per ejaculate when compared to the classical intracervical insemination procedure. In such a way can be increased significantly the degree of reproductive exploitation of genetically superior boars
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2025 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.