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Beef semen management practices in California dairy herds.

J. M. V. Pereira

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06-24-2020

Abstract:

308
Beef semen management practices in California dairy herds.
J. M. V. Pereira*1,2, D. Bruno3, M. I. Marcondes1, F. C. Ferreira2. 1Universidade Federal de Vicosa Vicosa, MG, Brazil, 2Department of Population Health and Reproduction, University of California Davis, CA, 3University of California Cooperative Extension Fresno, CA.

Beef semen (BS) usage in dairy cows has been employed as a reproductive management strategy. Our aim was to describe the CA dairy farmer's management practices on the use of BS. On Jan 17th, 2020 we mailed a 1,070 BS surveys to dairy producers in CA. Survey questions (n = 43) were divided into dairy information (n = 10), BS (n = 17), and sexed semen (SS, n = 6) usage. As of Feb 14th, 2020, 100 dairies (9.3%) representing 8.6% of all cows in CA (n = 149,456) had returned the survey. This abstract will present our preliminary results. Herd size averaged 1,590 milking cows (range 105—5,500) with 34.8 kg of milk/cow/d (range 18—43). Of the 100 respondents, 6% did not identify the herd breed, 71% were Holstein, 13% mixed (Holstein and Jersey), 8% Jersey and 2% crossbred. Most producers are using BS (n = 77, 77%), of which 64.9% are using Angus, followed by Wagyu (11.7%) and Limousin (9.1%). Preference of the calf ranch (42.7%), cost (40%) and calving ease (24%) were the main factors driving the selection of the BS. The majority of the respondents (70%) started BS use less than 3 years ago, and 28.9% of all dairies are breeding more than 30% of all eligible cows with BS. Dairies are considering cow's reproductive performance (73.7%), lactation number (46.1%), milk production (40.8%) and genomic testing (35.5%) as their criteria to select them to receive BS. Regarding lactation number, the majority of herds (59.2%) start breeding with BS on 3rd lactation and plus followed by 34.7% on 2nd, 30.6% on heifers, and 11.6% on 1st. Concerning reproductive performance, 45.3% start breeding after 3rd breeding, 32.8% after 4th, and 28.1% after 5th or more. Extra profit and managing the extra number of heifers were the mains reasons for using BS. Among the BS users, 63% also use SS. Lactation number (45.2%) and genomic testing (42.5%) are the main factors to select cows for SS breeding. When asked about their perspectives for the crossbred future market, 58.1% of the respondents using BS agreed that the crossbred calf price will decrease. Survey results demonstrated the widespread use of beef semen in dairies in CA and the main breeding strategies adopted by dairy farmers.

Keywords: beef semen, dairy management, California.

Biography: Animal Scientist, PhD student in Ruminant Nutrition and Production at the Universidade Federal de Vicosa,�visiting research scholar�at University of California - Davis.