Use Progesterone To Induce Estrous In Late-Calving Beef Cows For AI Or Natural Service

May 11, 2015

By Aaron Berger

Calves born in the first 30 days of the calving season have many advantages over later born calves. Early born calves weigh more at weaning and replacement heifers born early in the calving season are more likely to conceive early in the breeding season as a yearling.

Research has shown two-year-old heifers that calve early in the calving season are more productive throughout their lives than later-calving herd mates.

In a fixed-breeding season, late-calving cows are less likely to become pregnant in the subsequent breeding season than early-calving cows. Cows calving early will have more opportunity to have multiple estrous cycles during the breeding season and therefore be more likely to conceive. The economic loss associated with later-born calves and the higher tendency of late-calving cows to not conceive highlights the benefits of inducing estrus earlier than may naturally occur for later-calving cows.
Progesterone use

Research has shown the use of a progesterone controlled internal drug releasing device (CIDR) for 7 days can shorten the time it takes for cows to come into heat after calving. The use of a CIDR can induce ovulation and initiate cycling earlier than may occur naturally, in cows that are at least 20 days post calving. By initiating estrus earlier, cows are more likely to conceive earlier in the breeding season. This initial estrus induced through the use of a CIDR is fertile and cows can be bred either by artificial insemination or through the use of natural service.

Dr. Rick Funston (UNL Reproductive Physiologist) has worked with producers interested in advancing the subsequent breeding date in later calving cows. In one group of approximately 55 cows, pregnancy diagnosis with ultrasonography estimated an average advance in calving date of 30 days by using a 7-day CIDR protocol with prostaglandin upon CIDR removal and immediate bull exposure.
CIDR device use with natural service

Many producers associate the use of a CIDR device with estrus synchrony for the purpose of artificial insemination. However, a CIDR device may also be used effectively with natural service.

The CIDR label indicates that it is "for synchronization of estrus in suckled beef cows and replacement beef and dairy heifers, advancement of first postpartum estrus in suckled beef cows, and advancement of first pubertal estrus in beef heifers."

Cow-calf producers who utilize natural service may benefit from identifying non-cycling cows that are at least 20 days post calving and utilizing a 7-day CIDR protocol to initiate estrus that coincides with the start of the breeding season.

Source:unl.edu

Video: FLEECED! Sheep Shearer Hands Over Clippers!

It's sheep shearing day at Ewetopia Farms! ?? Our Dorset lambs and ewes are getting fleeced — and for the first time, our shearer hands over his clippers to a beginner. We finish shearing the last of our adult ewes and this year’s Dorset ewe lambs.

From moving the sheep between barns, loading them into chutes, and watching the wool come off, this is always one of the most satisfying days on the farm. But this video has a twist — we welcomed a new helper, Gian, who’s not only lending a hand but also learning how to shear! With guidance from our experienced shearer, he got a crash course in sheep shearing and even tried his hand at shearing a couple of lambs himself.

You’ll see firsthand how both teacher and student handled this unique challenge. Shearing is more than just removing wool — it’s about sheep health, comfort, and giving us a closer look at the flock. It’s always amazing to see the transformation from woolly sheep to freshly shorn ewes and lambs.