Effect of Energy Intake on Reproductive Performance of Dairy Bulls. II. Semen Production and Replenishment

Association between scrotal circumference, live weight and sperm output in cattle

“…Testis measurements generally were positively correlated with the output of spermatozoa obtained by frequent ejaculation (Boyd & VanDemark, 1957;Almquist & Amann, 1961;Adrich, 1976). VanDemark & Maager (1964) noted a positive correlation between scrotal circumference and liveweight, especially in bulls over 18 months of age, although Amann (1970) was later unable to repeat this finding. Using wither height as an indication of body size, Hahn, Foote & Seidel (1969) found that generally there was a low correlation, below +0-39, with testis size, indicating that larger, faster growing bulls did not necessarily have larger testes than did smaller bulls of the same age.…”

Parental diet, pregnancy outcomes and offspring health: metabolic determinants in developing oocytes and embryos

“…sperm count and sperm motility) are decreased by undernutrition (Parker and Thwaites 1972;Robinson et al 2006). In bulls up to the age of 2 years, levels of nutrition affect testicular development and sperm production (Vandemark et al 1964;Gauthier and Berbigier 1982). Histological analysis reveals male nutrition to affect the diameter and proportion of the testes occupied by seminiferous tubules and seminiferous epithelium (Martin et al 2010).…”

240 Sire verification in multi-sire breeding systems

“…Although no work has been conducted assessing DMI of lame bulls it can be extrapolated from data on feedlot steers that this reduced intake would also apply to bulls, especially when in pasture conditions, or in group feeding situations where bulls must search or compete for food. It can then be hypothesized that some of the decreased sperm quality may be associated with low feed intake (Meacham et al 1963;VanDemark et al 1964;Rekwot et al 1988;Martin et al 1994). Bulls with low DMI are known to have reduced scrotal circumferences, reduced semen production, reduced number of sperm per ejaculate, and decreased sperm motility (Meacham et al 1963;VanDemark et al 1964;Rekwot et al 1988;Martin et al 1994).…”

“…Although Mwansa and Makarechian (1991) suggest that bulls should not be maintained on a high-energy diet, it is also important not to restrict diet too much. VanDemark et al (1964) showed that when bulls were restricted to 60% of the recommended total digestible nutrients (TDN) a reduction in semen production and number of sperm per ejaculate was found and bulls never fully recovered to their maximum semen production.…”