Risk Factors Influencing Conception Rate in Holstein Heifers before Artificial Insemination or Embryo Transfer
Abstract: The objective of
this study was to show the risk factors affecting the conception rate in
Holstein heifers after synchronization of estrus. A total of 275 Holstein
heifers housed in a free barn were used for the experiment. The herd was
visited regularly at four week intervals for synchronization of estrus using
Heatsynch and CIDR-Heatsynch protocols. A group of four to 14 animals,
depending on the availability, were referred to the experiment at each visit.
Estrus induction rates in the two protocols were 93.9% and 94.9%, respectively.
There was no difference in the conception rate between the two protocols.
Conception rate after artificial insemination (AI) or embryo transfer (ET) were
46.3% and 51.4%, respectively. The risk factors affecting conception rate in
heifers were daily weight gain (odds ratio [OR]= 4.673; P= 0.036) and body
condition score (BCS) (OR= 3.642; P= 0.018). Furthermore, estrus
synchronization protocol (OR= 1.774; P= 0.083) and the absence of corpus luteum
(CL) at the initiation of treatment (OR= 0.512; P= 0.061) had a tendency to
affect the conception rate, while age (OR= 0.715; P= 0.008) was a protective
factor to conception rate. In
conclusion, positive daily weight gain before AI or ET, higher BCS, younger
age, and the presence of CL at the initiation of estrus synchronization in
dairy heifers increased the likelihood to conceive.
Keywords: risk factors;
conception rate; Holstein Heifers; induced estrus
Penulis: M. Yusuf, T. Nakao,
S. T. Long, S. Fujita
Kode Jurnal: jppeternakangg160050