Management aspects of induced twinning in beef suckler cows using in vitro fertilised embryos.
Twin and single pregnancies were induced in two groups of oestrus-synchronised beef cows by using a combination of artificial insemination and the transfer of in vitro fertilised (IVF) embryos. Single IVF embryos transferred non-surgically to the uterine horn contralateral to the corpus luteum of 43 previously inseminated cows resulted in a calving rate of 72 per cent with a twinning rate of 38.7 per cent. In 45 cows, two IVF embryos were transferred non-surgically to one uterine horn resulting in a calving rate of 51.1 per cent with a twinning rate of 39.1 per cent. The median gestation length for cows bearing twins was 10 days shorter than that of cows bearing single calves (P < 0.001). The proportions of cows that received assistance at calving were similar for twin and single births (57 per cent vs 45 per cent, P > 0.05), but the incidence of retained fetal membranes was much higher after the birth of twins (62 per cent vs 3 per cent, P < 0.001). Nineteen per cent of twin calves were stillborn compared with 6 per cent of single calves (P > 0.05). The median birthweight of the twin calves was 32 kg (68 per cent of the median weight of single calves). The nutrition of twin-bearing cows in late pregnancy was adequate when assessed in terms of their plasma glucose, non-esterified fatty acid and beta-hydroxybutyrate concentrations. Serum immunoglobulin concentrations were similar in single and twin calves suggesting that the passive transfer of antibody was not compromised in the twin calves.
Penny
C D
CD
Department of Veterinary Clinical Studies, Royal (Dick) School of Veterinary Studies, Easter Bush, Roslin, Midlothian.
Lowman
B G
BG
Scott
N A
NA
Scott
P R
PR
Voelkel
S
S
Davies
D A
DA
D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D000831:Animals, Newborn / Q000502:physiology; D001724:Birth Weight; D001774:Blood Chemical Analysis / Q000662:veterinary; D002417:Cattle / Q000502:physiology*; D002418:Cattle Diseases / Q000209:etiology; D004420:Dystocia / Q000209:etiology / Q000662:veterinary; D004624:Embryo Transfer / Q000662:veterinary*; D004973:Estrus Synchronization; D005321:Extraembryonic Membranes / Q000473:pathology; D005260:Female; D005307:Fertilization in Vitro / Q000662:veterinary*; D005313:Fetal Death / Q000209:etiology / Q000662:veterinary; D007315:Insemination, Artificial / Q000662:veterinary*; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000662:veterinary; D011270:Pregnancy, Animal / Q000502:physiology*; D011272:Pregnancy, Multiple / Q000502:physiology*; D011897:Random Allocation; D014427:Twins