ANGUS BEEF BULLETIN EXTRA

November 20, 2018 | Vol. 11 : No. 11

management

Avoid a Heifer Development Wreck

Lifetime of cow productivity begins with heifer selection.

The dust has cleared, the steer calves are loaded and gone to market. Now, your attention turns to the heifer replacement pen. How you manage that heifer now can set her up for a long, productive life — or failure in her first two years.

Selecting heifers as replacements

The first step in heifer development is selecting the right heifers for the keep pen. The time during the calving season when the heifer is born is the most important factor in determining her lifetime productivity, said Rick Funston, professor and reproductive physiologist with University of Nebraska during the 2018 Feeding Quality Forum in Omaha, Neb.

“The biggest driver in cow profitability is when she was born in the breeding cycle,” said Funston. “Heifers born in the first 21 days of the calving season stay in the herd longer and wean heavier calves than heifers born in the second or third 21 days of a calving season.”

The first heifers to sell should be any heifer you treated for bovine respiratory disease as a nursing calf, according to Che Trejo, beef technical services veterinarian for Zoetis.

The time during the calving season when the heifer is born is the most important factor in determining her lifetime productivity.

“We simply can’t reverse the lung damage after that point, and she isn’t a good replacement candidate,” Trejo said.

Preventing disease challenges

The next step is making sure the heifers are protected from reproductive diseases so they have the best chance of getting bred in the first 21 days.

“It’s a shift in protecting her from respiratory disease before weaning to protecting her from reproductive disease going forward,” said Trejo. “We want to get at least 45 days past weaning before we give the first dose of modified-live virus (MLV) reproductive vaccine. The timing of brucellosis (Bang’s disease) vaccination lines up well to give the first dose in most herds.”

Trejo recommends giving two doses of an MLV reproductive vaccine prior to the heifer being bred for the first time. He suggests that producers use a vaccine that protects against the following diseases:

  • Bovine viral diarrhea (BVD), types 1 and 2;
  • Infectious bovine rhinotracheitis (IBR) virus and IBR abortions;
  • Campylobacter fetus (vibriosis); and
  • Leptospirosis.

While most MLV vaccine labels indicate that the second dose of vaccine should be given at least 30 days prior to breeding, Paul Walz, veterinarian at Auburn University’s College of Veterinary Medicine, suggested at least 45 days prior to breeding to allow two heat cycles before breeding, during his Feeding Quality Forum presentation.

In both cases, the timing allows the heifer to have a complete immune response to the vaccination without any interference during breeding.

Nutrition and target weight

Adequate nutrition is critical during the heifer’s development, as well as throughout and after breeding for improved pregnancy rates. However, nutrition continues to play a key role throughout pregnancy with the ultimate goal of producing strong, vigorous calves.

Traditionally, the recommendation is for heifers to reach 65% of their mature weight by the time they are ready to breed, said Trejo. More recent research has looked at a lower target weight (55% of mature weight) and its impact on breeding rates.1

Research suggests there is some effect on conception rates to artificial insemination (AI), but there was not a significant difference in overall pregnancy rates between heifers developed to 55% of mature weight and 65% of mature weight.1

“If you have the flexibility to keep more heifers than you need, then put some pressure on the heifers to breed in a lower nutritional plane,” said Trejo. “Ideally, we will develop heifers to gain between 1.5 pound (lb.) and 2.2 lb. per day. The key is to keep her growing throughout pregnancy, her first calf and rebreeding for a second.

“Ideally, we need a heifer development strategy until they have their second calf,” said Trejo. “They aren’t cows yet because they are growing and developing, along with growing a full set of teeth.”

Trejo reiterates the following tips for developing heifers:

  • Select older heifers, born in the first 21 days of the season;
  • Don’t keep any heifers treated for BRD as a nursing calf;
  • Administer two doses of an MLV vaccine with fetal protection prior to breeding; and
  • Target gains of 1.5-1.8 lb. per day so heifers attain at least 55% of mature weight by breeding time.

Editor’s note: This article was provided by Zoetis, which offers its website FetalCalfProtection.com for more information on selecting vaccines for heifer development programs.

1Hall JB, Glaze Jr. JB. Heifer nutritional development and the target weight debate, in Proceedings. Applied Reproductive Strategies in Beef Cattle 2016;131-144. Source available on www.appliedreprostrategies.com.

Photo by Shauna Rose Hermel.