Seasonal variations in scrotal circumference and semen characteristics of Naimi and Najdi rams in Saudi Arabia

Abstract

In the present study, the authors analysed the effects of seasonal variations on the scrotal circumference and semen characteristics in two ram breeds in Saudi Arabia, namely Naimi and Najdi. Five rams of each breed were used in this experiment. Scrotal circumference and semen characteristics were evaluated in each ram twice a month throughout the year. Significant differences were observed in the scrotal circumference between various seasons. The largest production of semen was recorded mainly in spring, whereas the lowest semen volume was produced in summer. The pH of the semen was slightly alkaline and significantly lower in autumn than in spring. Furthermore, the highest value of the total number of sperm per ejaculate was observed in spring for both breeds. The results indicated that mass motility increased significantly in autumn compared with winter, spring, and summer. Progressive motility was significantly lower during the months of summer and spring. However, no significant differences were recorded between autumn and winter. Hence, the presence of significant seasonal variations in semen quantity and quality of Naimi and Najdi rams suggests the viability of increased utilization of rams in spring and autumn for semen collection and reproductive practices. ______________________________________________________________________________________ Keywords: Mass motility, progressive motility, semen volume, sperm concentration. # Corresponding author: mgalmutary@uod.edu.sa A wide variety of sheep breeds exists owing to geographical isolation, cross breeding, selection, and genetic drift. Najdi and Naimi are two native sheep breeds that are found in the Kingdom of Saudi Arabia. Both are fat-tailed sheep. However, the Najdi breed is black coated, whereas the Naimi breed is white in colour with a distinguishing brown head (Ali & Naomi, 1992; Muneeb et al., 2012). In comparison with other domestic livestock species, sheep are widely known for marked seasonality of breeding activity. The phenomenon is regulated by the annual cycle of daily photoperiod. Sheep are sexually active mainly in late summer and early autumn when the day length is shorter. Moreover, physiological and sexual variations in rams are less pronounced than in ewes. For instance, rams are sexually active throughout the year. However, ovulation in ewes is limited to certain periods (Rosa & Bryant, 2003).With the introduction of artificial insemination (AI) in animals, there is growing need to acquire knowledge about the variations in semen characteristics. Semen quality in terms of sperm ejaculate is affected dramatically by the environment in temporary and permanent ways, which include ambient temperature, feeding, age, period of daylight, conditions during semen collection, and management (Foote, 1978). The reproductive activity of sheep and the effect of season on the quality of semen have been studied by many researchers. A study on the effect of seasons on the reproductive ability of rams raised in United Arab Emirates (UAE) suggest...

Semen Characteristics of NARI Suwarna Rams during Breeding (Winter) and Non-breeding (Summer) Seasons

“…In contrast, studies have reported significant seasonal variation for volume, colour, wave motion and individual motility in Hamdani rams (Juma and Al-Kassab, 2009) and increased semen volume in summer, semen colour being milky to creamy during summer and spring while having a thin density in autumn and winter with higher mass motility and individual motility in the summer season. Similar seasonal variations were also reported for volume, wave motion and individual motility in Dorper (Malejane et al, 2014), Naimi and Najdi rams (Al-Anazi et al, 2017). Further, some studies have reported seasonal variations for volume but not for wave motion and individual motility (Milczewski et al, 2015;Belkhiri et al, 2017) whereas, other studies have reported seasonal variations for wave motion and individual motility but not for semen volume (Chella et al, 2017).…”

Seasonal Variations in Semen Parameters of Zulu Rams Preserved at 10°C for 72 H During Breeding and Non-Breeding Season

“…Whereas high progressive motility was attained during non-breeding than breeding season which were in line to (Kulaksiz and Sen, 2019). Previous studies reported seasonal variations of sperm quality numerous breeds ranging from United Arab Emirates crossbred rams (Ibrahim, 1997), Suffolk and Ile-de-France rams (Mandiki et al, 1998), indigenous breeds of Greece (Karagiannidis et al, 2000b) and Naimi and Najdi rams of Saudi Arabia (Al-Anazi et al, 2017). Therefore, this high progressive motility obtained during non-breeding indicate that Zulu rams produce acceptable semen quality in both breeding and non-breeding season.…”

“…According to (Chella et al, 2017) semen pH in Zulu rams' semen ideally ranges from 5.9 to 7.3. Moreover, (Al-Anazi et al, 2017), reported that semen pH in Naimi and Najdi rams was somewhat alkaline and lower during autumn than spring. Nevertheless, contradicted to (Talebi et al, 2009;Wang et al, 2015), where they found semen pH to not differ (p>0.05) throughout the year.…”

Seasonal Variations in Semen Quality, Testosterone Levels, and Scrotal Size following Dietary Flaxseed Oil and Ascorbic Acid in South African Indigenous Rams

“…Semen pH increased when treatment diets were introduced in all seasons. According to Al-Anazi et al [ 48 ], semen pH varies with the season, being alkaline and significantly lower during autumn than in spring. However, ram semen pH should range between 5.9 and 7.3 when grazing on pastures [ 42 ].…”