A note on fertilization and embryo production in superovulated cattle with various levels of subcutaneous fat tissue

Abstract

One hundred and five Holstein cattle, with a mean body weight of 668 kg, were superovulated using a total dose of 18 mg FSH. Five animals did not have corpora lutea (CL). No ova or embryos were recovered from 12 of the 100 animals which had CL. A total of 810 ova/embryos were collected from the remaining 88 animals and 432 of these were of transferable quality. The mean (range) measurements for subcutaneous fat deposition in samples taken at slaughter from the back, rump and ventral abdominal wall were 14 mm (3 to 34), 7 mm (0·7 to 33) and 7 mm (0·8 to 32), respectively. The number of transferable embryos and fertilized ova decreased as fat levels increased, but the differences between the groups were not significant (P > 0·05). There was a positive relationship between the number of CL and (a) the number of fertilized ova, and (b) the number of transferable embryos (r = 0·53, P < 0·001 and r = 0·48, P < 0·001). The correlation between the number of fertilized embryos and the number of transferable embryos was r = 0·91, P < 0·001.

The effects of varying dose and pattern of administration of ovine FSH on the response to superovulation in performance tested, juvenile Simmental heifers

“…Newcomb, Rowson and Trounson (1978) achieved a greater degree of superovulation in heifers (<3 to 5 years old) than in cows (3-5 to 7 years old); embryo recovery rates were, however, higher in cows than heifers. Bielanski and Yadav (1990) showed that body condition (fat depth) affected superovulatory response in obese dairy cattle but we were unable to identify such a relationship in obese juvenile Simmental beef heifers (Tregaskes, Broadbent, Roden, Hutchinson and Dolman, 1996). Armstrong and Leung (1990) suggested that the lower yield of viable embryos was due to the immaturity of the reproductive tract which may compromise sperm and embryo transport.…”