Abstract #111
Section: Reproduction (orals)
Session: Reproduction 1
Format: Oral
Day/Time: Monday 11:30 AM–11:45 AM
Location: Room 207/208
Session: Reproduction 1
Format: Oral
Day/Time: Monday 11:30 AM–11:45 AM
Location: Room 207/208
# 111
Fertility of fresh and frozen sex-sorted semen in dairy cows and heifers in seasonal-calving pasture-based herds.
C. Maicas*1,2, I. Hutchinson1, J. Kenneally1, J. Grant3, A. Cromie4, J. Moreno5, R. Vishwanath5, E. Maia5, P. Lonergan2, S. Butler1, 1Animal and Grassland Research and Innovation Centre, Teagasc, Moorepark, Fermoy, Co. Cork, Ireland, 2School of Agriculture and Food Science, University College Dublin, Dublin, Ireland, 3Research Operations Group, Teagasc, Ashtown, Dublin, Ireland, 4Irish Cattle Breeding Federation, Bandon, Co. Cork, Ireland, 5Sexing Technologies, Navasota, TX.
Key Words: sex-sorted semen, pasture-based system
Fertility of fresh and frozen sex-sorted semen in dairy cows and heifers in seasonal-calving pasture-based herds.
C. Maicas*1,2, I. Hutchinson1, J. Kenneally1, J. Grant3, A. Cromie4, J. Moreno5, R. Vishwanath5, E. Maia5, P. Lonergan2, S. Butler1, 1Animal and Grassland Research and Innovation Centre, Teagasc, Moorepark, Fermoy, Co. Cork, Ireland, 2School of Agriculture and Food Science, University College Dublin, Dublin, Ireland, 3Research Operations Group, Teagasc, Ashtown, Dublin, Ireland, 4Irish Cattle Breeding Federation, Bandon, Co. Cork, Ireland, 5Sexing Technologies, Navasota, TX.
The objective was to evaluate the reproductive performance of dairy heifers and cows inseminated with fresh and frozen sex-sorted semen (SS) in seasonal-calving pasture-based dairy herds. Ejaculates from 10 Holstein-Friesian bulls were split and processed to provide 1 of 4 semen treatments: (1) fresh conventional semen at 3 × 106 sperm per straw (CONV); (2) fresh SS at 1 × 106 sperm per straw (SS-1M); (3) fresh SS semen at 2 × 106 sperm per straw (SS-2M); and (4) frozen SS at 2 × 106 sperm per straw (SS-FROZEN). Semen from all treatments was used to inseminate cows and heifers following detection of spontaneous estrus during the 2 d following processing. Pregnancy per artificial insemination (P/AI) was determined using subsequent calving records supplemented with pregnancy diagnosis data when available. Separate generalized linear mixed models for heifers (n = 3,214) and cows (n = 5,493) were used to examine effects on pregnancy per artificial insemination (P/AI), with semen treatment (n = 4), bull (n = 10) and treatment by bull interaction as fixed effects, and herd as a random effect. Additional relevant variables for cows and heifers were also tested (e.g., DIM, parity, genetic traits), and retained where significant. CONV semen had greater P/AI than SS-FROZEN in heifers and greater P/AI than any SS treatment in cows. None of the SS treatments differed from each other (Table 1). P/AI increased with greater DIM, Economic Breeding Index and Body condition score, and decreased as parity number increased, but none of these variables interacted with semen treatment. The relative P/AI for frozen SS compared with conventional semen was greater (>84%) than previously reported in lactating cows, but fresh SS semen did not have greater P/AI compared with frozen SS.
Table 1 (Abstr. 111). Pregnancy/AI (P/AI, %) and performance of sex-sorted semen relative to conventional semen (SS/CONV, %) in dairy heifers and cows
a,bLSM within a column with different superscripts differ (P < 0.05).
| Treatment | Heifers | Cows | |||
| P/AI | SS/CONV | P/AI | SS/CONV | ||
| CONV | 60.9a | — | 48.0a | — | |
| SS-1M | 54.2ab | 88.9 | 37.6b | 78.4 | |
| SS-2M | 53.5ab | 87.8 | 38.9b | 81.0 | |
| SS-FROZEN | 52.8b | 86.7 | 40.6b | 84.7 | |
Key Words: sex-sorted semen, pasture-based system
