RESUMO
This study aims to investigate the gene expression of sperm-borne phospholipase C zeta (PLCζ), WW domain-binding protein 2N-Terminal Like (WBP2NL), and Tumor necrosis factor (TNF-α), as a negative control, in spermatozoa and their relationship with fertility and seminal quality in stallions. Ejaculates from 40 Criollo stallions were used, whose fertility was assessed on the basis of their pregnancy rate per cycle in at least two breeding seasons. Pregnancy rates ranged from 20% to 90% and were used to divide the stallions into two groups: High rates (≥ 50%) (n = 25), and Low rates (< 50%) (n = 15). A computer-assisted sperm analysis system - (CASA) analyzed semen after collection. Also were evaluated the physical and functional integrity of the plasmatic membrane and sperm morphology alterations. All stallions expressed PLCζ, WBP2NL, and TNF-α. PLCζ positively correlates with conception rate, total motility (TM), progressive motility (PM), plasmatic membrane functionality, and integrity. A simple linear regression was detected between pregnancy rate and PLCζ expression (P = 0.003), TM (P < 0.001) and PM (P < 0.001). PLCζ gene expression was higher (P = 0,012) in the High rates group than in the Low group. WBP2NL and TNF-α did not correlate with seminal quality and stallion's fertility. It was concluded that PLCζ gene expression in the spermatozoa might be used as a biomarker of fertility and seminal quality in stallions. Parameters of sperm kinetics also showed, positive correlation between TM, PM and pregnancy rate.
RESUMO
The main objective of the present experiment was to assess the effect of temporary weaning on the onset of estrus, ovarian follicular activity and secretion of luteinizing hormone in Bos indicus cows. Forty six mature cows were divided into three groups 1) calves were weaned for 72 h allowing auditory, olfactory and visual contact with their dams (VISUAL, n = 17), 2) calves without contact with their dams for 72 h (NC, n = 17) and 3) calves not weaned and in constant contact with their dams (CTRL, n = 12). Estrus was synchronized in all cows using CIDR for 9 days plus 2 mg of estradiol benzoate given at CIDR insertion. The VISUAL group had a greater (P < 0.05) proportion of cows in estrus (76.5%) compared to the CTRL group (16.7%), but no differences were found when compared to the NC group (58.8%). The VISUAL group had a greater proportion of animal that ovulated (76.5%) compared to CTRL (33.3%) and NC groups (64.7%; P = 0.059). Duration of estrus was shorter (P = 0.04) in the VISUAL (8.4 ± 4.4 hours) than in the NC (12.9 ± 13.4 hours) however, CTRL treatment (11 ± 1.4 hours) was not different from either of these two groups. LH concentration after implant removal was similar among treatments and started to increase at 36 h post CIDR removal. Only in the CTRL group was there an obvious increase by 54 h after implant removal. Follicular size increased in diameter from 36 h and were evident in treatments and control groups by 60 h (P < 0.05). The VISUAL treatment increased the number of cows ovulating and shortened the length of estrus. VISUAL and NC groups showed a similar response in follicular growth and pattern of circulating LH because of treatment.