Effect of type and quantity of concentrates on superovulation and embryo yield in beef heifers

• Published in: Theriogenology 1999-05, Vol.51 (7), p.1259-1266
• Main Authors: Yaakub, H., O'Callaghan, D., Boland, M.P.
• Format: Article
• Language: English
• Subjects: Animal Feed; Animal Nutritional Physiological Phenomena; Animals; beef heifers; Cattle - embryology; Chenopodiaceae; Cryopreservation; Diet; embryo; Embryo Transfer - veterinary; Embryo, Mammalian - physiology; Female; Hordeum; nutrition; Progesterone - administration & dosage; Silage; Superovulation
• ISSN: 0093-691X; 1879-3231
• DOI: 10.1016/S0093-691X(99)00070-9

Embryo yield and quality can be decreased following superovulation of cattle on high levels of concentrates. Concentrate type can alter rumen fermentation patterns and so affect energy availability and thus embryo quality. The objectives of this experiment were to examine the effect of 2 levels and 2 types of concentrate on superovulatory response and embryo quality in beef heifers. Beef heifers received grass silage as a basal diet and barley at 3 kg (n=20) or ad-libitum (n=19), or citrus/beet pulp at 3 kg (n=18) or ad-libitum (n=19) as the source of concentrate supplement. Silage was available ad-libitum for heifers offered 3 kg but was restricted to 1 kg DM/day for heifers on ad-libitum concentrate intake. Both concentrates contained 14% crude protein. After 100 d, heifers were treated with an intravaginal progesterone releasing device (CIDR) for 7 d, and superovulation was initiated 60 h before CIDR withdrawal. Heifers received pFSH (a total of 265 mg NIH-FSH-P1 equivalent) administered over 8 injections at 12 h intervals with the last 2 injections administered at 12 and 24 h after CIDR withdrawal, they were inseminated at 56 and 72 h after CIDR withdrawal without reference to estrus. Heifers, were slaughtered 6, 7 or 8 d after the first insemination, and embryos were flushed from the uterus with PBS and were graded morphologically. Statistical analyses were performed using analysis of variance. There was no interaction between level and type of diet, and thus data for the main effects are presented separately. Final live weights at the end of the experiment and carcass weights for heifers offered ad-libitum concentrate (643.8±6.9 kg; 354±8 kg, respectively) were higher (P0.05). Superovulatory responses (number of corpora lutea at slaughter) was gteater (P0.05). Heifers offered 3 kg concentrates produced greater (P