H. D. Norman,1 J. L. Hutchison, and R. H. Miller
Animal Improvement Programs Laboratory, Agricultural Research Service, USDA, Beltsville, MD 20705-2350
2009 J. Dairy Sci. (?)
© American Dairy Science Association,
2009. All rights reserved.
Individuals may download, store, or print single
copies solely for personal use.
Do not share personal accounts or passwords
for the purposes of disseminating this article.
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. Breeding year followed by service number accounted for the most variation in sexed-semen use for both heifer and cow breedings. 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 for percentage of herds with sexed-semen use (range of 25 to 58% for heifers and 8 to 16% for cows). Mean sexed-semen use 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%); for heifers, sexed-semen use was greatest in the Mideast, Mountain-Prairie, and Southeast (21 to 25%) compared with other regions (7 to 17%). Mean sexed-semen use 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 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%. Evaluations for active AI bulls with sexed semen available were superior to evaluations for 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.
(Key words: sexed semen, breeding, Holstein, Dairy Herd Improvement)