Use of sexed semen and its effect on conception rate, calf sex, dystocia, and stillbirth of Holsteins in the United States

Authors: Norman, H; Hutchison, Jana; Miller, Robert

Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/29/2010
Publication Date: 8/1/2010
Citation: Norman, H.D., Hutchison, J.L., Miller, R.H. 2010. Use of sexed semen and its effect on conception rate, calf sex, dystocia, and stillbirth of Holsteins in the United States. Journal of Dairy Science. 93(8):3880-3890.

Interpretive Summary: Sexed-semen breedings of Holstein heifers and cows on US dairy farms were characterized by parity, service number, herd size, herd milk yield, and region. Bulls with marketed sexed semen were compared to all bulls with conventional semen available. Trends showed rapid adoption (especially for heifers) since 2006 when sexed semen became commercially available, which could contribute to a surplus of milking animals at a time when milk prices and value of replacement stock is extremely low.

Technical Abstract: Sexed-semen use for breeding Holstein heifers and cows in Dairy Herd Improvement herds was documented by frequency and percentage for parity and service number as well as for herd region, size, and milk yield. Year of breeding accounted for the most variation in the amount of use of sexed semen for both heifer and cow inseminations, followed by service number. Sexed semen was used for 1.4, 9.5, and 17.8% of all reported breedings for 2006, 2007, and 2008, respectively, for heifers, and 0.1, 0.2, and 0.4% for cows. For heifers, 82% of sexed-semen use was for first service, whereas conventional semen tended to be used for subsequent services (85 to >99%); for cows, 61% of sexed-semen use was for first parity and 43% for first service of first parity. Across parities for cows, 68% of sexed-semen use was for first service; first and second services accounted for 88% of sexed-semen use for cows. Some regional variation was evident in percentage of herds that had used sexed semen (range of 25 to 58% for heifers and 8 to 16% for cows). Average amount of sexed-semen used for cows was greater in the Mideast, Midwest, Northeast, and Southeast (2 to 3%) than in the Mountain-Prairie, Northwest, and Southwest regions (<1 to 1%); percent of herds that had used sexed-semen for heifers was greatest in the Mideast, Mountain-Prairie, and Southeast (21 to 25%) compared with other regions (7 to 17%). Average amount of sexed-semen used tended to increase for heifers and decrease for cows as herd size increased (16% for heifers and 5% for cows in herds with <=50 animals compared with 18 to 19% and <2% for herds with >100 animals). For both heifers and cows, sexed semen use was more frequent for herds with lower milk yield (22% for heifers and 6% for cows in herds that produced <=8,000 kg) than in herds with higher milk yield (15 to 16% for heifers and 1% for cows for herds that produced >=11,000 kg). Availability of sexed semen was examined also for active AI Holstein bulls; of 700 bulls born in 1994 and later, 260 (37%) had sexed semen available as of the August 2009 USDA-DHIA genetic evaluation. When bulls were grouped by lifetime net merit decile (low to high), the percentage of bulls with sexed semen was 14, 17, 26, 27, 27, 47, 47, 55, 45, and 58%. Active AI bulls with sexed semen available had slightly higher evaluations than did average active AI bulls for yield traits, productive life, somatic cell score, daughter pregnancy rate, service-sire calving ease, service-sire stillbirth, sire conception rate, final score, and net merit.