Efficacy of Timed Embryo Transfer with Fresh and Frozen In Vitro Produced Embryos to Increase Pregnancy Rates in Heat-Stressed Dairy Cattle

Abstract

Our objective was to determine whether pregnancy rates in heat-stressed dairy cattle could be enhanced by timed embryo transfer of fresh (nonfrozen) or frozen-thawed in vitro-derived embryos compared to timed insemination. Ovulation in Holstein cows was synchronized by a GnRH injection followed 7 d later by PGF2 alpha and a second treatment with GnRH 48 h later. Control cows (n = 129) were inseminated 16 h (d 0) after the second GnRH injection. On d 7, a fresh (n = 133) or frozen-thawed (n = 142) in vitro-derived embryo was transferred to cows assigned for timed embryo transfer after categorizing the corpus luteum by palpation per rectum as 3 (excellent), 2 (good or fair), 1 (poor), and 0 (nonpalpable). Response to the synchronization treatment, determined by plasma progesterone concentration (ng/ml) < or = 1.5 on d 0 and > or = 2.0 on d 7, was 76.2%. Mean plasma progesterone concentration on d 7 increased as the quality of corpus luteum improved from category 0 to 3. Concentrations of progesterone in plasma were elevated (> or = 2.0 ng/ml) at 21 d in 64.7 (fresh embryo), 40.3 (frozen embryo), and 41.4 +/- 0.1% (timed insemination) of cows, respectively. Cows that received a fresh embryo had a greater pregnancy rate at 45 to 52 d than did cows that received a frozen-thawed embryo or timed insemination (14.3 > 4.8, 4.9 +/- 2.3%). Body condition (d 0) of cows influenced the pregnancy rate and plasma progesterone concentrations. In summary, timed embryo transfer with fresh in vitro-produced embryos in heat-stressed dairy cattle improved pregnancy rate relative to timed insemination.

Effect of supplementation of different growth factors in embryo culture medium with a small number of bovine embryos on in vitro embryo development and quality

“…Moreover, IVEP from slaughterhouse material provides a high number of oocytes or embryos (after in vitro maturation and fertilisation) at a low cost to carry out other associated embryo technologies such as cryobiology. In bovine, IVEP is especially interesting to mitigate the decrease in fertility suffered by dairy cattle during environmental heat stress conditions (Ambrose et al, 1999; -E-mail: miguel.silvestre@uv.es Al-Katanani et al, 2002) or to take advantage of the ovum pick-up technique (OPU). In the latter case, a small number of oocytes per female are usually recovered after OPU (approximately three to six oocytes recovered per nonstimulated cow and session; Rizos et al, 2005;Chaubal et al, 2006).…”

Environmental Stress Effect on Animal Reproduction

“…A few years earlier, Gilad et al, [4] reported that conception rates in Israel fell from 52% in winter to 24% in the summer. In summer, 80% of estrus may be undetectable [15]. Also indicated, Ryan et al, [22] that when the rectal temperature of the animals increased from 38.5°C to 40°C in 72 hours after insemination service, pregnancy rates can decrease up to 50%.…”

“…In other studies in Florida, [15] showed that in summer with heat and humidity conditions, pregnancy rates are down to 10%.…”

“…Several studies [12,15,23] have indicated that in cattle, embryonic development is highly sensitive to high temperatures, in the top three to 11 days after service; acquiring more heat tolerance as the gestation period progresses. It is known that the embryos obtained by in vitro fertilization (IVF) are more susceptible to heat stress than those obtained under natural conditions.…”

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

“…Besides to faster genetic progress, ET also has the potential to increase fertility in dairy cows experiencing heat stress (Putney et al, 1989;Ambrose et al, 1999;Baruselli et al, 2010;Rodrigues et al, 2004Rodrigues et al, , 2007Rodrigues et al, , 2011 and those diagnosed as repeatbreeders (Dochi et al, 2008;Rodrigues et al, 2011), because it bypasses problems associated with fertilization failure and disruption of the oocyte quality in dairy cows (Ferreira et al, , 2016. For example, Baruselli et al 2011, utilizing data from a large commercial herd in Brazil, showed that conception results can be increased in about ~8% (cooler months) to 20% (warmer months) percentage points with the use of ET when compared to AI (Fig.…”