Effect of education on ability of AI professionals and herd-owner inseminators to detect cows not in oestrus and its relation with progesterone concentration on day of re-insemination.

The effect of training background of persons performing artificial insemination (AI) (herd-owner inseminators (OWNER), AI technicians (AI-T), and fertility consultants (FC)) on pregnancy rate and their ability to detect cows not in oestrus were studied. A total of 1584 re-AI occasions on 754 dairy farms were included. Milk samples for progesterone (P4) analysis in all cases were collected, as were data on the herd, previous breeding attempts, oestrous signs, uterine tone, slipperiness of cervix, and co-operation of the cow. Further breeding attempts and next calving or culling date were sought from registers. The cases were distributed into three categories based on P4 concentrations; <6 nmol/l (no luteal activity, could be in oestrus), 6-10 nmol/l (some luteal activity), and >10 nmol/l (high luteal activity, not in oestrus). Of cows offered for re-AI 7.7% had P4 concentration >10 nmol/l, with no difference between OWNER farms and farms using AI service. OWNERs chose for AI more cows having intermediate P4 than farms using AI service (9.8% vs. 5.9%, p < 0.05). AI-Ts recommended no AI significantly less often than FCs (1.6% vs. 4.9%, p < 0.01). Both groups were equally right: 71% and 68% of cows that were recommended to have no AI had high P4 concentration. Due to courageous and correct rejection of cows with high P4, FCs inseminated proportionally more cows in low P4 and less cows in intermediate P4 than OWNERs (p < 0.05). Of cows finally inseminated, 36.7% became pregnant, with no difference between OWNER farms and farms using AI service. Fertility consultants had higher pregnancy rates than AI-Ts (39.6% vs. 32.6%, p < 0.05). Toneless uterus and sticky cervix at AI significantly correlated with AI occurring at the wrong time (p < 0.001). Behaviour of the cow at AI did not predict P4 concentration. In conclusion, 7.7% of cows offered for re-AI had high P4 concentration. Training of AI personnel increased their ability to detect and reject these cows.

The effect of ascorbic acid during biopsy and cryopreservation on viability of bovine embryos produced in vivo.

Multiple ovulation embryo transfer (MOET) is used to make more rapid progress in animal breeding schemes. On dairy farms, where female calves are more desired, embryo sex diagnosis is often performed before embryo transfer. Fresh transfers have been favored after biopsy due to cumulative drop in pregnancy rates following cryopreservation. The aim of this study was to explore whether exposure to ascorbic acid (AC) during biopsy and freezing increases the viability of biopsied embryos after cryopreservation. Data on presumptive pregnancy and calving rates of biopsied and cryopreserved/overnight-cultured embryos were gathered. Results showed differences in presumptive pregnancy rates between the groups: 45% for both biopsied-cryopreserved groups (control and AC), 51% for biopsied-overnight-cultured embryos and 80% for intact-fresh embryos. Differences between the groups were also apparent in calving rates: 22% for biopsied-cryopreserved control embryos, 31% for biopsied-cryopreserved AC-embryos, 23% for biopsied-overnight-cultured embryos and 63% for intact-fresh embryos. It is concluded that manipulated embryos are associated with lower presumptive pregnancy and calving rates compared with intact-fresh embryos. The highest calving rates for groups of manipulated embryos were achieved in the AC-group. Therefore, addition of AC can be recommended if biopsy is combined with freezing before transfer.

Embryo production from superovulated Holstein-Friesian dairy heifers and cows after insemination with frozen-thawed sex-sorted X spermatozoa or unsorted semen.

The aim of this study was to evaluate embryo production in superovulated Holstein-Friesian dairy heifers and cows inseminated with either X-sorted spermatozoa (2 million/dose) or unsorted semen (15 million/dose). Experiment 1 at the research farm involved eight heifers, six cows and semen of one Holstein bull. All transferable embryos were diagnosed for sex. Experiment 2 included embryo collections on commercial dairy farms: X-sorted spermatozoa from three Holstein bulls were used for 59 collections on 28 farms and unsorted semen from 32 Holstein bulls were used for 179 collections on 79 farms. Superovulations were induced by eight declining doses of FSH (total of 12 ml for heifers and 19 ml for cows) starting on days 8-12 of the estrus cycle. Inseminations began 12h after the onset of estrus and were performed two to four times at 9-15 h intervals. Low-dose X-sorted inseminates were deposited into uterine horns and unsorted semen was placed into the uterine body. In Experiment 1, on average 70.3 and 75.0% of embryos recovered from heifers, and 48.4 and 100% of embryos recovered from cows were of transferable quality in X-sorted and unsorted groups, respectively. The proportion of transferable female embryos produced approximately doubled when insemination was with X-sorted spermatozoa compared to insemination with unsorted semen (heifers 96.4% versus 41.1%; cows 81.1% versus 39.8%). In Experiment 2, estimated 53.9 and 65.5% of embryos recovered from heifers, and 21.1 and 64.5% of embryos recovered from cows were of transferable quality in X-sorted and unsorted groups, respectively. Proportions of unfertilized oocytes were 21.1 and 10.6% for heifers and 56.0 and 14.4% for cows in X-sorted and unsorted groups, respectively. Consequently, cows inseminated with X-sorted spermatozoa produced significantly smaller proportions of transferable embryos (p<0.005) and significantly larger proportions of unfertilized oocytes (p<0.001) than those inseminated with unsorted semen. Proportions of quality 1 or degenerated embryos were similar for the two treatments in both heifers and cows. Within treatments, bulls did not significantly affect the proportions of transferable, unfertilized or degenerated oocytes/embryos. It was concluded that using low-dose X-sorted spermatozoa rather than normal-dose unsorted semen for the insemination of superovulated embryo donors can improve the proportion of transferable female embryos produced but this potential may not be achieved in commercial practice, particularly in cows, because of reduced fertilization rates when using low doses of X-sorted spermatozoa.