Progesterone release profile and follicular development in Holstein cows receiving intravaginal progesterone devices.

The aim of this study was to evaluate the progesterone (P4) release profile provided by eight commercial intravaginal P4 devices, as well as the effect of circulating P4 concentrations produced exclusively by these devices on the development of the dominant follicle (DF) in non-lactating multiparous Holstein cows. All cows were submitted to the same experimental design starting with the insertion of a reused P4 device (2 g - original P4 load) for 7 d, followed by two treatments of cloprostenol sodium (PGF; 0.482 mg), 24 h apart, 6 and 7 d after device insertion. Just before device removal, a Norgestomet ear implant was inserted and, 2 d later (Day 0), simultaneously to Norgestomet withdrawal, cows received one of the tested intravaginal devices and 2 mg of estradiol benzoate (EB) im. In Exp.1 (n = 22; three replicates), cows were randomized to receive: CIDR (1.38 g); PRID-Delta (1.55 g); Prociclar (0.75 g); or Repro sync (2 g). In Exp. 2 (n = 29; four replicates), cows were randomized to receive: Cue-Mate (1.56 g); DIB 0.5 (0.5 g); DIB (1 g); PRID-Delta (1.55 g); or Sincrogest (1 g). Blood samples were collected before P4 device insertion (Day 0), 12 h later and daily over 15 d (1 d after P4 device removal). Ultrasound examinations were performed to evaluate growth of the DF on Days 0, 7, 8, 9, and 10. Results are presented as mean ± SEM and differences were considered when P ≤ 0.05. Overall, the circulating P4 profile and mean circulating P4 over 10 d differed among treatments. However, no effects were observed on the DF diameter and follicular growth rate from Day 7-10 after P4 device insertion. In Exp. 2, devices that provided higher circulating P4 concentrations were associated to a slower DF growth during the treatment period. Finally, this study provided a better understanding of the P4 release profile produced by intravaginal P4 devices as well as their effect on circulating P4 concentrations and DF development in non-lactating Holstein cows.

Genetic market in cattle (Bull, AI, FTAI, MOET and IVP): financial payback based on reproductive efficiency in beef and dairy herds in Brazil

A number of reproductive biotechnologies are currently available to multiply offspring from high genetic merit animals to enhance reproductive efficiency and profitability both in dairy and beef herds. Some of these technologies such as fixed time artificial insemination (FTAI), when correctly implemented,generally allow greater reproductive performance than natural breeding. Besides the use of frozen-thawed semen during artificial insemination, cattle recipients can also be synchronized to receive embryos (produced in vivo or in vitro) at set dates with fertility results that usually outperforms natural breeding as well as artificial insemination (AI), particularly during warm seasons and in repeat breeders cows. Altogether, the use of hormonal programs to synchronize ovulation time simplify field routine, can easily fix physiological limitations related to postpartum anestrus (beef cows), poor estrus detection efficiency due to less evident estrus signs (dairy cows), making AI and ET viable to commercial herds both in terms of results and economical returns.(AU)

Genetic market in cattle (Bull, AI, FTAI, MOET and IVP): financial payback based on reproductive efficiency in beef and dairy herds in Brazil

A number of reproductive biotechnologies are currently available to multiply offspring from high genetic merit animals to enhance reproductive efficiency and profitability both in dairy and beef herds. Some of these technologies such as fixed time artificial insemination (FTAI), when correctly implemented,generally allow greater reproductive performance than natural breeding. Besides the use of frozen-thawed semen during artificial insemination, cattle recipients can also be synchronized to receive embryos (produced in vivo or in vitro) at set dates with fertility results that usually outperforms natural breeding as well as artificial insemination (AI), particularly during warm seasons and in repeat breeders cows. Altogether, the use of hormonal programs to synchronize ovulation time simplify field routine, can easily fix physiological limitations related to postpartum anestrus (beef cows), poor estrus detection efficiency due to less evident estrus signs (dairy cows), making AI and ET viable to commercial herds both in terms of results and economical returns.

Number of oocytes retrieved per donor during OPU and its relationship with in vitro embryo production and field fertility following embryo transfer

The association of OPU-IVEP is an important instrument to drive genetic progress. In vitro embryo production (IVEP) has remarkably expanded in the last decade compared to in vivo embryo production. Because of the high repeatability of oocyte retrieval within oocyte-donors, studies exploring the relationship between the number of oocytes recovered per OPU section with IVEP efficiency, as well as with field fertility (pregnancy results following embryo transfer; P/ET) are extremely important to guide cow-donor selection and optimize field reproduction efficiency and the herds genetic gain. Based on this rationale, our group conducted a retrospective analysis of a large database comprising IVEP records from several cattle breeds, including Bos indicus and Bos taurus for either beef or dairy purposes. A total of 205,140 oocytes recovered from 7,906 OPU procedures of 6,902 donors (5,227 beef and 1,675 dairy) of Brazilian farms were analyzed. Beef breeds analyzed were Nelore (Bos indicus) and Senepol (Bos taurus) and dairy breeds Were Gyr (Bos indicus) and Holstein (Bos taurus). According to our analysis, the IVEP in beef cattle had a great improvement throughout the last years, with a remarkable increase in numbers of pregnancies per OPU compared to late 90s (averaging only 1 pregnancy per OPU in 1998 vs 2,4 in 2014). As for the distribution of oocytes retrieved, both Bos indicus beef (Nelore = 27.2) and dairy (Gyr = 23.8) breeds seem to yield greater average numbers of oocytes per OPU compared to Bos taurus (Senepol = 21.8; Holstein = 19.3).(AU)

Number of oocytes retrieved per donor during OPU and its relationship with in vitro embryo production and field fertility following embryo transfer

The association of OPU-IVEP is an important instrument to drive genetic progress. In vitro embryo production (IVEP) has remarkably expanded in the last decade compared to in vivo embryo production. Because of the high repeatability of oocyte retrieval within oocyte-donors, studies exploring the relationship between the number of oocytes recovered per OPU section with IVEP efficiency, as well as with field fertility (pregnancy results following embryo transfer; P/ET) are extremely important to guide cow-donor selection and optimize field reproduction efficiency and the herd’s genetic gain. Based on this rationale, our group conducted a retrospective analysis of a large database comprising IVEP records from several cattle breeds, including Bos indicus and Bos taurus for either beef or dairy purposes. A total of 205,140 oocytes recovered from 7,906 OPU procedures of 6,902 donors (5,227 beef and 1,675 dairy) of Brazilian farms were analyzed. Beef breeds analyzed were Nelore (Bos indicus) and Senepol (Bos taurus) and dairy breeds Were Gyr (Bos indicus) and Holstein (Bos taurus). According to our analysis, the IVEP in beef cattle had a great improvement throughout the last years, with a remarkable increase in numbers of pregnancies per OPU compared to late 90’s (averaging only 1 pregnancy per OPU in 1998 vs 2,4 in 2014). As for the distribution of oocytes retrieved, both Bos indicus beef (Nelore = 27.2) and dairy (Gyr = 23.8) breeds seem to yield greater average numbers of oocytes per OPU compared to Bos taurus (Senepol = 21.8; Holstein = 19.3).