Group-training of rams at puberty for artificial vagina-mediated semen collection and its influence on semen quality and sexual behavior

Abstract

There is a paucity of information with respect to group-training for artificial vagina and its influence on semen characteristics and sexual behavior of young untrained rams. A total of 18 healthy Najdi rams (with an initial body weight of 40-45 Kg and 7-8 month-old) were consequently used herein to test the usefulness of group-training for artificial vagina-mediated semen collection during the breeding season. Rams were randomly segregated into three groups ( n = 6 rams per protocol), and the whole experiment was lasted for 10 weeks. The 1 st group was subjected to a training protocol where one untrained ram was placed for 20 min with a teaser ewe, while the 2 nd group were subjected to a protocol where one untrained ram was placed for 20 min with one trained ram and a teaser ewe, whereas the 3 rd group were subjected to a protocol where three untrained rams were placed for 20 min with one trained ram and a teaser ewe. The obtained results clearly ( P < 0.05) showed that training young rams in group has increased their sperm concentration and sexual stimulation, shortened the period of their training time, and descriptively had a complete training efficiency. The sexual stimulation of young untrained rams was intensified by the competition between rams in the co-presence of a trained ram. Collectively, these data may suggest that group-training of rams at puberty is a better protocol for AV-mediated semen collection compared to individual training. Some shortcomings were noted herein, but research dealing with this subject may very well improve the reproductive performance of young untrained rams.

Systematic review of hormonal strategies to improve fertility in rams

“…Through vast amounts of information presented by different studies involving the analysis of male reproductive hormones, it has been confirmed that the sexual activity of rams is under the control of androgenic hormones that act at the level of the hypothalamus (preoptic area) (see complete reviews of Orihuela-Trujillo, 2012). One of the main hormones released by rams is testosterone, which influences sexual and metabolic activity and varies throughout the year; it is present at low concentrations outside the reproductive season, while testosterone levels increase above the threshold required for the ram to show sufficient sexual behaviour to detect a female in oestrus ( Bahadi et al, 2023 ) and induce her to cover and become pregnant within the same season. Ungerfeld (2021a) systematically characterises sexual behaviour and describes the main scenarios that can influence sexual development from lambing to adulthood.…”

“…The aim of this review is not to describe all of the factors involved in or influencing sexual behaviour and the male effect, as comprehensive reviews have been previously undertaken over the years (see full reviews by Pretorius, 1972 ; Tilbrook and Cameron, 1990 ; Rosa and Bryant, 2002 ; Ungerfeld et al, 2004 ; Perkins and Roselli, 2007 ; Orihuela-Trujillo, 2012; Roselli, 2020 ; Ungerfeld, 2021a , b ). However, it is necessary to mention that consistent studies have been carried out over the years investigating factors that influence sexual behaviour (see Figure 2 ), where the different factors that can influence both wool and hair rams have been shown ( Bahadi et al, 2023 ). It is important to bear in mind that there are differences which, in one way or another, affect the mating of a ram to an oestrus ewe to a greater or lesser extent, as well as the achievement of optimal gestation of two offspring.…”