Abstract
Multiple pregnancies have devastating consequences on the herd economy of dairy cattle. This observational study examines incidence patterns based on data from the ultrasonographic examination of 1130 multiple pregnancies in cows in their third lactation or more carrying twins (98.8%), triplets (1.1%), or quadruplets (0.08%), and 3160 of their peers carrying singletons. Cows became pregnant following a spontaneous estrus with no previous hormone treatments. Irrespective of a significant decrease (p < 0.0001) in the conception rate (28-34 days post-insemination) during the warm period of the year, the multiple pregnancy rate was similar for both warm (26.5%) and cool (26.3%) periods. The incidence of unilateral multiple pregnancies (all embryos in the same uterine horn) was higher than that of bilateral pregnancies (at least one embryo in each uterine horn): 54.4% versus 45.6% (p < 0.0001). This difference rose to 17% during the warm season (p = 0.03). Pregnancy was monitored in unilateral multiple pregnancies until abortion or parturition (n = 615). In the warm period, the parturition rate was 43% compared to 61% recorded in the cool period (p < 0.0001). Thus, a warm climate is the main factor compromising the fate of multiple pregnancies. Some clinical suggestions are provided.
Highlights
Low fertility and abortion are a major source of economic losses for dairy herds [1]
Since there were no differences in terms of years for the different parameters investigated, data were grouped as a single year (Table 1)
The findings of our study suggest that the development of two pre-ovulatory follicles, one in each ovary, is impaired under heat stress conditions to a greater extent than when there are two co-dominant follicles in the same ovary
Summary
Low fertility and abortion are a major source of economic losses for dairy herds [1]. The economic burden of a twin pregnancy has been estimated at up to $225 [6]. Twin pregnancies are classified into bilateral (one fetus in each uterine horn) and unilateral (both fetuses in the same uterine horn, right or left). The risk of pregnancy loss during the first trimester of gestation for cows carrying twins may be from three to seven times higher than for cows carrying singletons, and from five to nine times higher for unilateral than for bilateral twins [7]. The risk of twin pregnancy is much more common in older cows [8,9] and so is the associated risk of abortion [7,10].
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
