title: Effects of AI protocol and time interval from onset of estrus to AI on conception rate in Japanese Black cows.
abstract: Two different artificial insemination (AI) protocols were investigated to determine the effect of the time interval from the onset of estrus (as detected by a pedometer) to the AI on the conception rate in Japanese Black cows. Seventy-three cows were divided into two groups that received AI either after the induction of synchronized ovulation (synchronized AI group; n = 26) or at the time of observed estrus (control AI group; n = 47). Each group was further divided into two subgroups, which were artificially inseminated either 0-12 h (early AI group; n = 21) or 12-24 h (late AI group; n = 52) after the onset of estrus. There was no significant difference in the conception rate between the synchronized AI and control AI groups. The AI protocol and the detection of estrus using a threshold of counted steps (as measured by a pedometer) in this study could be effective for planned reproduction management without the observation of standing estrus in Japanese Black cows.
authors.affiliation: Faculty of Agriculture, University of Miyazaki, Miyazaki             Soo Agricultural Mutual Aid Association, Kagoshima, Japan.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Hemmi
authors.forename: Ikuo
authors.initials: I
authors.lastname: Kobayashi
authors.forename: Makoto
authors.initials: M
authors.lastname: Kajisa
authors.forename: Go
authors.initials: G
authors.lastname: Kitahara
authors.forename: Kiichi
authors.initials: K
authors.lastname: Fukuyama
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Harada
authors.forename: Shunichi
authors.initials: S
authors.lastname: Kamimura
mesh_terms: D000818:Animals; D002417:Cattle / Q000502:physiology*; D004971:Estrus / Q000502:physiology*; D004972:Estrus Detection / Q000295:instrumentation; D005260:Female; D005306:Fertilization / Q000502:physiology*; D007315:Insemination, Artificial / Q000379:methods*; D010060:Ovulation / Q000502:physiology; D010062:Ovulation Induction / Q000379:methods; D011247:Pregnancy; D013997:Time Factors