Effect of artificial cooling and its combination with timed artificial insemination on fertility of holstein heifers during summer

Abstract

In order to evaluate artificial cooling and timed artificial insemination (TAI) protocol on fertility during summer months, 90 Holstein heifers were randomly and equally assigned to three treatments: a) control group (S) with visual heat detection and insemination a.m-p.m after heat detection; b) a group (TAI+C) using a norgestomet ear implant (3 mg) plus an injection of 3 mg of norgestomet and 5 mg of estradiol valerate. The implant was removed after 9 d and 500 IU i.m of eCG were administered at the same time, plus a cooling period with spray and fans beginning at time of implantation until 21 d after AI; c) a third group (C) with heat detection and Al a.m-p.m, starting the artificial cooling when animals initiated in the treatment until 21 d after Al. Temperature-humidity index (THI) averaged 85 during the trial. T3 concentration increased in treatment groups. Conception rate among treatment groups was similar (P>.05). Artificial cooling increased heifers comfort and TAI plus cooling did not show any improvement on fertility. © GSP, India.