One-Day Supplementation With Tyrosine Did Not Affect Reproductive Traits Of Sows

Kansas State University Swine Reserach. Primiparous and multiparous sows received a single dietary supplement of L-tyrosine in their feed on the day after weaning, and the efects on various reproductive traits were evaluated. Sows received either none (control; n = 21) or 45.5 mg L-tyrosine/lb BW (tyrosine; n = 22) on the day after weaning. In Exp. 1, days from weaning to estrus (5.1 1 vs 5.3 .9 d) and ovulation rate (number of corpora lutea on ovaries on d 5 after estrus) (16.3 4.4 vs 16.2 4) were similar in control and tyrosine-supplemented sows. In Exp. 2, (control; n = 63; tyrosine; n = 53) days to estrus were extended by tyrosine supplementation (6.4 .5 d) compared to control sows (4.6 .5 d), but total numbers of piglets born (10.6 .4 vs 10.1 .4) were similar in control- and tyrosinetreated groups. Therefore, a single dietary supplementation with tyrosine on the day after weaning failed to influence interval to estrus, ovulation rate, or litter traits.