Management discussed for heifer developmentWritten by Natasha Wheeler
Riverton – “There is more to breeding heifers and cows than simply getting them bred and bred the first time,” stated retired Montana State Extension Specialist Ray Ansotegui at Fremont County Farm and Ranch Days on Feb. 11.
Ansotegui explained that the major goals for heifer development include calving early in the calving season, conceiving early in the breeding season, providing adequate milk and producing a calf every 365 days.
Without proper nutrition in heifers he explained, “She is going to be older before she reaches puberty, conception isn’t going to be as good, and there will be increased calving difficulty, sickness and mortality. Also, her calf will be born later and lighter.”
A consistent feeding schedule for gradual weight gain is one way that he suggests maintaining proper nutrition.
“When it’s been a big, long winter and all of the sudden, it’s March, we often push extra feed to the heifer to get her to the target weight,” he commented.
Instead, he suggested using feed rationed throughout the season so the heifer reaches her target weight gradually throughout the year.
“She has a genetic potential to put on red meat at two to 2.5 pounds a day,” he stated.
When her feed is pushed at the end of the season, and she is gaining 3.5 pounds a day, Ansotegui explained that the extra pounds are put on as fat tissue.
“She will have the weight, but she won’t have the maturity,” he said.
One problem that he noted from this type of fat build up was increased calving difficulty.
“When we get that heifer putting on fat, she is getting a lining of fat inside the pelvis,” he noted.
The extra tissue causes less space in the birth canal for the calf to exit through.
“We have also ruined the lifetime productivity of that heifer because that is when she is developing her udder,” he added.
There is a short window for udder production, and no further development of the mammary tissue occurs after puberty.
Another feeding strategy Ansotegui recommended was separating heifers by body weight.
“Usually, we put all of our replacement heifers together in a big pen, and we feed them so much per heifer,” he said.
He suggested separating them into two groups, with the heavier half in one pen and the lighter half in another.
“We are talking about the same amount of feed,” he commented, indicating that the heifers are fed the same amount each day per animal as they would be if they were all penned together.
Study results show that the larger heifers remain nearly the same size, but the smaller ones show improvement in gain.
“When they aren’t competing with their big sisters, they can gain up to half a pound per day more,” he stated.
This practice may be easier to execute in a feedlot than a pasture.
“The big problem is we have to get up and down and close the gate,” he noted.
Ansotegui also encouraged feeding older cows apart from the younger animals.
“We must feed two-year-olds separately. They cannot be put in with mature cows,” he said.
As two-year-olds, the heifers are getting new teeth, which makes it harder for them to compete with the older cows for feed.
Also, he explained, “The heifer is socially unacceptable. She is at the bottom of the pecking order.”
Another nutritional recommendation provided by Ansotegui was adding a protein supplement during the last trimester and early lactation of a heifer or cow’s pregnancy.
Looking at a study done in Nebraska, he stated, “The only time the cows in the study were not together was when the study group was getting their protein supplement.”
Otherwise, the cows were kept together and treated the same way.
Ansotegui illustrated, “At the 205-day weight, the heifers averaged at 498 pounds versus 481 pounds,” with the heavier calves being those whose mothers had received the protein supplement.
“The rebreeding weight averaged at 608 pounds for calves with supplemented mothers versus 586 pounds for the others,” he added.
Overall pregnancy rate in the heifers proved to be better as well, with 94 percent in those whose mothers had supplement versus 73 percent in those who did not.
In another study, researchers exposed a group of heifers to some bulls.
“We are talking about sterile bulls in this situation,” Ansotegui commented.
Leaving the bulls in with the heifers affected the onset of puberty.
“Exposure changed the puberty date by about 40 days, and 51 percent of those heifers became pregnant within 21 days versus only 17 percent of the heifers that were not exposed,” he explained.
Lastly, Ansotegui warned producers about transporting cows after they have been artificially inseminated (AIed).
“In the first seven days, we aren’t going to hurt anything,” he said.
At 17 or 18 days after the cows have been inseminated, the calf is just beginning to form, and it is extra-sensitive to the jostling of the mother cow as she is being moved from one place to another.
If cows are moved around this time, he warned, “Those cows might come back into heat.”
He recommended planning AI and transportation schedules around the sensitive breeding times of the cows.
“There are many challenges in beef production but management can help,” stated Ansotegui.