141 Reproductive characteristics of post-pubertal lambs after being rendered short scrotum

Abstract

Abstract A follow-up study was conducted to validate observations from an earlier trial on reproductive function in ram lambs following short scrotum castration. Again, East Friesian x Lacaune male dairy lambs from a commercial sheep dairy born in February and March were either left intact (IN, n=25), rendered short-scrotum (SS; n=18), or completely banded (WE; n=25) within 10 d of birth. At a mean age of 65 d, lambs were moved to the study site and managed as one group on cool season forages and supplemented with grain at 2–3% BW. At a mean age of 172 d, lambs were tested for libido in a 5 min pen test, and semen was collected from 7 IN and 7 SS lambs. Four estrus-induced teaser ewes were used for libido testing and semen collection by artificial vagina. Lambs were harvested the day after testing/collection, and reproductive tracts were recovered from 5 IN and 5 SS lambs at random. Differences between male lamb types were analyzed using PROC GLM. No statistical differences (P >0.05) in reproductive behaviors were observed between IN and SS, though number of services and kicks were numerically higher in IN than SS (1.3 vs. 0.45; 1.6 vs. 0.73). No reproductive behaviors was observed in WE. Ejaculate volume was not different between IN and SS (0.56 vs. 0.49 ml), but percent motile sperm (45 vs. 6 %; P< 0.01) and sperm concentration (1.52 vs. 0.05 billion/ml; P< 0.05) were higher in IN then SS lambs. Total testis and epididymis weight were also higher (P< 0.01) in IN than SS lambs (291 vs. 109 g; 53.8 g vs. 17.7 g). Additionally, epididymal sperm reserves were higher (P< 0.05) in IN than SS (9.42 vs. 0.89 billion) lambs. Results confirm our earlier findings that reproductive function was greatly reduced, but did not cease in short scrotum ram lambs.