Effect of induced body condition score differences on sexual behavior, scrotal measurements, semen attributes and endocrine responses in Malpura rams under hot semi-arid environment

Abstract

The study was conducted for a period of 45 days to assess the influence of body condition scoring (BCS) on reproductive efficiency of Malpura rams in terms of sexual behaviour, scrotal measurements, semen attributes and endocrine responses. The rams were randomly divided into three groups as group I (BCS = 2.5; n = 7), group II (BCS = 3.0; n = 7) and group III (BCS = 4.0; n = 7). Apart from grazing for 8 h a day, the rams were provided with concentrate mixture at the rate of 100, 300 and 500 g to groups I, II and III respectively to attain their respective BCS. Under these differential feeding regimes, sexual behaviour scrotal measurements, semen characteristics and endocrine parameters were studied at 15-days interval. Sexual behaviour, scrotal volume, scrotal circumference, testicular width, testicular length and scrotal skin thickness differed significantly (p < 0.05) between lower BCS group (group I) and higher BCS groups (groups II and III). The semen volume, mass motility and progressive sperm motility were recorded significantly (p < 0.05) higher in group II and lowest in group I. However, the sperm concentration did not differ significantly between the groups. The mean plasma testosterone concentration differed significantly (p < 0.05) between lower BCS group (group I) and higher BCS groups (groups II and III). Circulating plasma hormone concentrations were influenced due to the BCS. Plasma cortisol, T(3) and T(4) increased as the BCS improved from lower to higher. In conclusion, better reproductive efficiency of rams of moderate BCS (3.0 and 3.5) than rams of lower (2.5) and higher BCS (4.0) indicates the importance of maintaining optimum body condition of breeding rams under hot semi-arid environment.

The effect of nutritional stress on sperm motion characteristics and sexual behaviour of rams in a semi-arid tropical environment

“…The condition of the body induced by nutritional stress had a significant effect on the sexual behaviour of Malpura rams (Maurya et al, 2010). The sexual parameters recorded in the present study showed that the number of mountings for the first ejaculation, time taken for the first ejaculation, and Figure 1.…”

“…In the present study, plasma testosterone was significantly (P < 0.05) lower in feed-restricted animals as compared with control rams and, therefore, testosterone-induced sexual behaviour was also reduced in feed-restricted animals. In a similar experiment, Maurya et al (2010) also reported reduced testosterone levels and reproductive behaviours of Malpura rams. Malau-Aduli et al (2003) reported that additional nutritional supplementation aids body weight gain and peaks testosterone concentration in bucks.…”

“…Changes in available energy and feed intake alter the endocrine axis and HPG axis. At the time of energy deficiency, an animal would divert the energy available for brain function and cognition that ultimately will hamper reproduction (Maurya et al, 2010). Braden et al (1974) reported that the level of feeding influences sperm production of Merino rams.…”

“…Each ram was scheduled in a random order for two consecutive ejaculations. After ejaculation, the semen samples were immediately taken to the laboratory and evaluated for: 1. volume: measured directly in millilitres to the nearest 0.1 ml using a graduated glass collection cup, 2. concentration: determined using a spectrophotometer, previously calibrated with a haemocytometer, and expressed as 10 6 · ml -1 , and 3. sperm motion characteristics: objectively evaluated by a computer-assisted sperm analysis (CASA) technique using a motility analyzer Hamilton-Thorn Biosciences HTM-IVOS version 12.1 M (Beverly, MA, USA; Maurya et al, 2010).…”

“…to moderate body conditioned Malpura rams in terms of most reproductive parameters (Maurya et al, 2010). The Booroola Fecundity gene (FecB) belongs to transforming growth factor β (TGF-β) superfamily (Fabre et al, 2006).…”