Abstract
Thirty healthy Sohagi ram lambs with an average age of 188.6±7.3 days were used to study the effect of pre-pubertal growth rate on some physiological parameters and sexual behavioral patterns at puberty. Ram lambs were divided into three groups (10 animals per each group) according to the previous growth rate until 6 months of age. Groups were marked as fast, medium and slow growing. Animal groups were housed in closed barns with access to an open area. Results showed that age and weight of ram lambs at puberty were significantly affected (P<0.05) by the pre-pubertal growth rate. Ram lambs in the fast growing group were reached to onset puberty firstly at 272.6 days with body weight (BW) 37.1 kg on average then ram lambs in medium group (284.8 days with BW 32.7 kg), while ram lambs in slow growing group were the last (314.1 days with BW 32.5 kg). Blood testosterone concentration at puberty was not significantly different among growing groups (1.494± 0.03 ng/ml on average, ranged from 1.287 to 1.902 ng/ml). Testes measurements from 6 months of age until puberty show that ram lambs in fast growing group had the highest values of testes length, circumference and volume followed by those in medium and slow growing group. Sexual behavioral observation showed that flehmen and mounting behavior were significantly higher for ram lambs in fast growing group (5.63 and 6.75 number/12h) than slow growing group (4.25 and 5.38 number/12h) while in medium growing group were intermediate (4.88 and 5.88 number/12h). From these findings, could be concluded that age, weight and sexual behavioral patterns of Sohagi ram lambs at puberty were affected by pre-pubertal growth rate, and the breeders should strive to achieve good growth rates for their lambs before puberty which led to improving reproductive performance.
Highlights
The efficiency of sheep production meat production in developing countries is important and depends mainly on the reproductive efficiency of the sheep
This work aimed to study the effect of pre-pubertal growth rate on some physiological parameters and sexual behavioral patterns of Sohagi ram lambs at puberty
Healthy thirty single births of Sohagi ram lambs with an average age of 188.6±7.3 days were divided into three groups (10 animals per each group) according to the previous growth rate from birth until 6 months of age
Summary
The efficiency of sheep production meat production in developing countries is important and depends mainly on the reproductive efficiency of the sheep. Male lambs with early puberty and distinctive sexual behavior can improve flock fertility during breeding and indirectly genetic improvement (Ibarra et al, 2000). Characterization of puberty and early sexual development is a valuable tool for genetic selection within the breed (ElShahat et al, 2014). Researchers interested in age at puberty are agreed that achieving an early age at puberty is associated with the time of birth and the nutritional planes (Khalifa et al, 2013). Moulla et al (2018) revealed that the complexity to define accurately onset of puberty in species with seasonal reproduction activity.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
