Association between energy status early postpartum and subsequent embryonic mortality in high-yielding recipient cows.

High-yielding Holstein-Friesian recipients (n = 43) were used in order to investigate the relation between energy balance status during the early postpartum period and subsequent embryonic mortality after transferring good-quality frozen embryos. Blood samples were collected during the second, third, fourth, fifth, sixth and seventh weeks postpartum in order to measure energy status indicators. These indicators include ß hydroxyl butyric acid (BHBA), non-esterified fatty acid (NEFA), total cholesterol (T-chol), glucose and blood urea nitrogen (BUN). Moreover, body condition scores (BCS) were assessed during the same period. Pregnancy diagnosis by ultrasonography at the 28th day postestrus and embryo viability was ascertained until 45 days postestrus in order to detect late embryonic mortality (LEM). The pregnancy rate on day 28 was 44.2% (19/43); however, five cows (11.6%) experienced LEM by day 45. Based on the non-return rate at day 24, non-pregnant animals, as diagnosed by ultrasonography, were allocated into animals with longer estrus intervals than 24 days (32.5%; mid-embryonic mortality (MEM) group) and animals returning to estrus by day 24 postestrus (23.5%; early embryonic mortality (EEM) group). At week 5 postpartum, BCS was significantly (P < 0.05) lower in the LEM group than that of pregnant (PREG), EEM and MEM groups. NEFA was significantly higher in animals that experienced LEM (LEM group) at week 7 postpartum (289.6 ± 47.0 µEq/L; P < 0.01) than that of PREG (196.8 ± 16.0 µEq/L), EEM (157.2 ± 18.6 µEq/L) and MEM groups (191.5 ± 14.4 µEq/L). In conclusion, lower BCS at week 5 postpartum and higher NEFAs at week 7 postpartum may be associated with subsequent LEM in high-yielding recipient cows.

Effects of growth hormone gene polymorphism on lipogenic gene expression levels in diaphragm tissues of Japanese black heifers.

Two SNPs, i.e. L127V and T172M, of bovine growth hormone (GH) causing the presence of GH gene haplotypes A, B, and C was previously shown to alter intramuscular fatty acid (FA) composition in Japanese Black (JB) heifers. To determine the SNP effect on somatotropic hormone concentration and lipogenesis, we measured plasma GH, insulin, and insulin-like growth factor-1 (IGF-1) concentrations. We also measured mRNA levels of fatty acid synthase (FASN), stearoyl-coA desaturase (SCD), and sterol regulatory element binding proteins-1 (SREBP-1) and FA composition in diaphragm tissues. Heifers with genotype CC had the lowest plasma insulin concentration and FASN and SCD mRNA levels among genotypes. FASN mRNA levels in haplotype A tended to positively correlate with saturated FA (SFA) content and negatively correlated with C18:2 and unsaturated FA (USFA) contents. SCD mRNA levels in haplotype A positively correlated with monounsaturated FA (MUFA) contents and negatively correlated with C18:0 content. They also tended to positively correlate with C16:1, C18:1, and USFA contents and USFA/SFA ratio and negatively correlate with SFA content. Taken together, GH gene polymorphism affects the lipogenic genes expression levels and their relationships with fatty acid compositions in diaphragm tissues of JB heifers at 31 months of age.

Effect of synchronisation of ovulation on ovarian profile and days open in holstein cows diagnosed as nonpregnant 26 days after timed artificial insemination.

The objective of this study was to clarify the effects of a second protocol of ovulation synchronisation starting on day 26 after timed artificial insemination on ovarian profile and days open in dairy cows diagnosed as nonpregnant. Ninety-four Holstein-Friesian cows received intramuscular injections of a GnRH analogue (GnRH), 100 microg fertirelin, on day 0 and a prostaglandin F(2alpha) analogue (PG), 5 mg etyprostontromethamine, on day 7. GnRH was again administered 48 h after the PG injection, and timed artificial insemination was performed 16 to 20 h later (Ovsynch/TAI). Twenty-six of the 94 cows returned to oestrus within 26 days after TAI and were inseminated. Of the other 68 cows, 44 were not pregnant and were randomly allocated to undergo another Ovsynch/TAI protocol (Resynch group; n=23) or AI only after detection of oestrus (Control group; n=21). The ovarian and hormonal profiles were compared between the first and second Ovsynch protocol periods in the Resynch group. The diameter of the dominant follicle and plasma oestradiol-17 beta concentration at the second GnRH injection were significantly greater than those at PG injection during the second Ovsynch period. Ovulation was synchronised in all of the animals in the second Ovsynch period. The AI submission rates, mean AI intervals and pregnancy rates of the Resynch and Control groups were 100% and 57.1%, 36.0 +/- 0.0 and 43.2 +/- 10.9 and 30.4% and 14.3%, respectively. The mean AI interval was 7 days shorter and the pregnancy rate was higher in the Resynch group than in the Control group, although no significant differences were found due to the small number of the animals. In conclusion, the Resynch protocol initiated on day 26 after TAI in the first protocol has the potential to reduce days open and increase the pregnancy rate in dairy cows.