Abstract
Body morphometry and temporary weaning (TW) associated to two protocols of fixed-time artificial insemination (FTAI) with intravaginal progesterone releasing device (IPRD) upon pregnancy rates were evaluated. Cows, at 45-59 days post-partum, were randomly divided into group 1 (n=147) and group 2 (n=197). Group 1: received 1g progesterone (IPRD) and 2mg estradiol benzoate on day 0 (EB-D0); 150μg D-cloprostenol on day 7 (PGF-2α-D7); 0,5mg estradiol cypionate and (TW-48 hours) on day 9 (EC+TW-D9); FTAI on day 11 (D11); group 2: IPRD+EB (D0); PGF-2α+EC+TW (72 hours) on D8; FTAI (D11). The pregnancy rate was higher in cows submitted to TW (72 hours) than in cows with TW (48 hours), or rather, 49.74% vs 30.60% (p<0.05). There was a statistical difference (p<0.05) in groups 1 and 2 between pregnant or non-pregnant cows with regard to body weight (412kg vs 400kg and 419kg vs 390kg) and body condition score (BCS) (3.33 vs 3.08 and 3.53 vs 3/32) respectively. Further, 72-hour weaning associated to the applied protocol improved the pregnancy rate. The evaluation of BCS during post-partum may adjust the start of the breeding season.
Highlights
With a pregnant period of approximately 280 days, cows should conceive between 80 and 85 days after birth.anestrus may occur during this period (SALES, 2011)
They were treated on day zero (D0) with 2 mg of estradiol benzoate - EB (Gonadiol ) intramuscular mode (IM) and the placing of an intravaginal progesterone release device with 1g – intravaginal progesterone releasing device (IPRD)
Group 2 (G2) = 197: the cows were fed on D0 with EB and the placement of IPRD; on D8 the IRPD was removed and PGF-2 and EC associated with RTB was conducted for 72h
Summary
With a pregnant period of approximately 280 days, cows should conceive between 80 and 85 days after birth. High anestrus rate, associated with low efficiency in the detection of heat among cows in the estrum cycle, provides low service rates. Pregnancy rates in milk-feeding cows are approximately 25% (CACHAPUZ, 1997) and the use of treatments with progestagens associated to the temporary removal of the calf (TRC) makes easier artificial insemination in extensive breeding of suckling cows (JAUME & MORAES, 2001). The employment of hormonal protocols for fixed time artificial insemination (FTAI) is justified to provide a high rate service and eliminate the need of estrum detection (ZANELA et al, 2010). In the case of animals in post-partum anestrus and with good body scores, a source of progesterone/ progestagen, estrogen and/or other hormones (BARUSELLI et al, 2003) and semen quality (OLIVEIRA et al, 2012; KASIMANICKAM et al, 2012) are associated for the synchronization of ovulation and FTAI. Current assay evaluates body morphometry and the temporary removal of calves (TRC) in two protocols of fixed time artificial insemination (FTAI) by intravaginal progesterone release device (IPRD), on pregnancy rates
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