A Review of the Use of Ultrasound for Reproductive Purposes in Beef Cattle
JOPLIN, Mo. (Aug. 31, 2011) — For many years, rectal palpation has been a mainstay of veterinarians for pregnancy diagnosis, and that will likely continue. But ultrasound has grown in importance over the past two decades because it can tell more, earlier and with less risk.
Scott Poock, University of Missouri (MU) veterinarian and dairy specialist, elaborated on those advantages while giving a series of live demonstrations at the Joplin Regional Stockyards Wednesday evening, Aug. 31, as part of the Applied Reproductive Strategies in Beef Cattle (ARSBC) meeting.
Noting the calibrated instrument screen, Poock provided a play-by-play account. “Here’s the head of the calf. You can see it is about 4 cm long, so that is 75 to 80 days. Here’s the umbilical cord, the spine, ribs, the beating heart. That’s important because you want to know it’s alive,” he said.
At that age the calf is “the size of a small rat,” but beyond the umbilical cord the presence of a scrotum indicated a male. Females can be discerned a bit sooner, as early as 55 days, Poock said.
“A great time to process a herd for diagnosis is 90 days after fixed-time AI (FTAI), he noted. “I can sex the AI calves and the first cleanup round, plus determine pregnancy on the third round.”
Confessing, “I’m not 100% accurate,” Poock noted the most experienced technicians are 92% up to 100%. Some of the variation could also relate to facility and time spent with each.
“I have done 30 in an hour, and nearly 90 in an hour,” he said, depending on how fast they are presented and days bred as well.
A reference table from research veterinarians Colloton and Stroud published in the proceedings lists the sizes of observed structures in the calf fetus with correlating days pregnant.
Poock spoke during an evening session of the ARSBC symposium hosted Wednesday evening, Aug. 31, at the Joplin Regional Stockyards. Summaries of other presentations at the ARSBC wil be available online at www.appliedreprostrategies.com. Compiled by Angus Productions Inc. (API; publisher of the Angus Journal and the Angus Beef Bulletin), the site is made possible through sponsorship by the Beef Reproductive Task Force, SEK Genetics, and liveauctions.tv. Coverage will include summaries of the speaker presentations, PowerPoints, proceedings and audio.
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