Producers should start considering cow management for rebreeding
Calving season has kicked off for many producers and it’s important to start thinking about managing cows during the early postpartum phase for a successful breeding season.
University of Nebraska-Lincoln (UNL) Cow/calf Extension Specialist Kacie McCarthy discusses how producers can manage postpartum anestrus during a UNL BeefWatch podcast on March 4.
Postpartum anestrus is the interval of infertility which cows experience after calving, she explains. During this time, the uterus is returning to its normal size, shape and position, and repairing itself to start another pregnancy.
This process, referred to as uterine involution, is completed in approximately 20 to 40 days following calving, if no complications arise.
McCarthy notes, due to short calving windows, late-calving cows and a limited breeding season can be a challenge for producers.
Producers who plan effectively for reproductive health and limit the impact of anestrus can ensure cows are set up for the upcoming breeding season.
“Producers should try to get cattle cycling early on in the breeding season,” shares McCarthy. “This will help cows acheive higher pregnancy rates and increase opportunities to become pregnant during the limited breeding season.”
Postpartum interval
Cows need time to recover from the high nutrient and physical demands of a growing fetus.
“Cows have 80 to 85 days to start their estrus cycle,” explains McCarthy. “Hopefully, cows will maintain a yearly calving interval and not fall behind.”
Producers who don’t manage the postpartum interval (PPI) successfully are a major cause of reproductive loss, especially in younger cows, McCarthy adds.
During the first ovulation after calving, producers may notice a shorter estrous cycle and subfertility in those females.
“Due to this, cows need to start their estrous cycle prior to the start of the breeding season to become pregnant,” McCarthy adds. “If cows don’t show signs of estrous, or are still in anestrus, the chance for those females cycling or becoming bred early enough in the breeding season decreases.”
“Producers should be asking how to manage cows who calve late or are not cycling early enough after calving,” she says. “Once cows fall behind the herd, it is hard for them to catch up unless they are left open for a year.”
Late-calving cows
Late-calving cows can create problems throughout cow/calf operations. Cows who calve late will rear a smaller, lighter calf at weaning, resulting in the loss of money for producers.
McCarthy notes, “Producers are losing money when cows calve late, so of course they want to know how to get cows to cycle faster.”
“A controlled intravaginal drug release (CIDR) can be used to start the heat cycle of late-calving cows earlier,” explains McCarthy. “A CIDR is a slow-release progesterone device commonly used as a heat synchronization tool.”
“A CIDR can also start a heifer’s heat cycle, she adds. “Data has shown inserting the CIDR 20 days after calving, and no sooner, can initiate cycling earlier than what may occur naturally.”
Even if artificial insemination is not being utilized, estrus synchronization can help shorten the PPI of thin cows in the breeding season.
Additionally, she adds, optimal reproductive performance of a herd requires
cows with a body condition score (BCS) of five or better. Utilizing heat synchronization tools, including prostaglandin, may have advantages for producers regarding prevention of late calving.
Body condition score
Many producers fail to realize BCS can affect the fertility of cattle. BCS also affects a cow’s ability to bounce back after calving.
McCarthy comments, “Body condition score is an effective management tool to estimate energy reserves of a cow.”
She continues to share body condition at calving has the greatest impact on rebreeding performance.
“Producers should evaluate the BCS of their cowherds,” McCarthy states. “Body condition before calving and throughout breed seasons allows producers to make nutritional changes. This ensures females are in proper body condition.”
Producers who manage nutrient intake and BCS of cows before and after calving can contribute to improved reproductivity within their herd.
For reproductive success, producers should be aiming for a BCS score of five to 5.5 on the scale of one to nine’ for mature females and 5.5 to six for first calf heifers by the breeding season.
McCarthy shares several studies indicate cows that gain BCS during the last trimester tend to have shorter PPI compared to cows just maintaining body condition.
“Nutritional adjustments within the last trimester to increase calving BCS can potentially impact reproductive performance,” McCarthy continues. “Nutritional adjustments should be part of a nutritional management strategy.
Madi Slaymaker is the editor of the Wyoming Livestock Roundup. Send comments on this article to roundup@wylr.net.
