Early puberty attainment for heifers can be nutritionally influenced
“We can utilize nutrition to help push heifers to have the best opportunity to get bred early,” says Shelby Rosasco, University of Wyoming Extension beef specialist, during a Beef Reproduction Task Force webinar on Feb. 15, 2022. “We can also utilize nutrition to make sure heifers are reproductively mature and reach puberty.”
Rosasco notes nutrition can be used to the advantage of ranchers when planning how to develop replacement heifers. Post-natal nutritional and developmental programming shows heifers can be nutritionally programmed during the first year of their lives.
“We can actually use nutrition to impact puberty attainment and potentially program the timing of the onset of puberty attainment. We can also potentially program the ovarian reserve,” Rosasco adds.
Management decisions can certainly impact puberty attainment, emphasizes Rosasco, who notes data shows nutrition can impact puberty attainment both pre- and post-weaning.
“When we really get into the data, we see we can have a pretty significant impact on the timing of puberty and program when puberty is going to occur with some pre-weaning nutrition,” she explains. “We have really important developmental windows early in life.”
The pre-pubertal period from four to roughly eight months of age can be a target to ensure heifers have the best opportunity to attain puberty and decrease the age at which puberty is attained.
“A study by Gasser and others in 2006 tried to answer the question of whether early weaning could hasten puberty,” Rosasco explains.
In the study, heifers were assigned to one of three treatments: early weaning and a high-concentrate diet, early weaning and a controlled diet and normal weaning with a controlled diet. In early weaning, heifers were weaned at 104 days.
“The timing of puberty was really similar between our early weaned control and normal weaned heifers. We didn’t necessarily have a significant decrease in the age at puberty attainment or hasten when puberty onset occurred,” she summarizes.
“But, in our early weaned heifers fed a high-concentrate diet, we can see a significant decrease in the mean age at puberty, so we were able to hasten puberty by target feeding a high-concentrate diet early in life in these heifers,” she adds.
Cardoso and others looked at utilizing a stair-step nutrition regimen with the goal of programming puberty attainment. All the heifers were weaned at 3.5 months of age and placed on one of four treatment diets – a low control aimed at one pound per day of gain, high control aimed at gaining 2.2 pounds per day – stair-step one and stair-step two.
The stair-step diets were targeted to program the onset of puberty attainment. Stair-step one started at a high rate of gain, then dropped to a low rate, repeating the sequence a second time, while stair-step two reversed the treatment of stair-step one, starting with a low rate of gain.
The group fed a low control diet aimed at gaining one pound per day saw a decrease in the number of heifers attaining puberty, as well as the age of puberty attainment, compared to the high controls and the stair-step treated heifers.
The high control and the stair-step one heifers had similar results, attaining puberty early on, between 10 and 12 months of age. The majority of heifers on the stair-step two diet attained puberty between 11 and 13 months of age.
“This suggests timing of puberty can be controlled or manipulated by nutritional management,” Rosasco explains. “We know we can impact puberty based on when we feed levels of a high-concentrate diet or target nutrition. Increased nutrition between four and six months of age had a greater influence on accelerating puberty.”
Rosasco warns, “We want to also be cognizant we don’t have periods of precocious puberty because this can certainly be detrimental to performance and is not recommended. Targeting a higher rate of gain between six and nine months of age, targeted to achieve puberty between 11 and 14 months of age, avoided increased incidents of precocious puberty.”
Cattle breed influence
Rosasco notes puberty attainment may be more of a challenge in Bos taurus and Bos indicus cattle.
“In Bos taurus cattle, we have done a good job in putting selection pressure on puberty attainment,” she explains. “We know we don’t have as many issues with puberty attainment in our British animals as we see in Bos indicus animals.”
Using these nutritional regimens can be helpful, however, if puberty attainment is a challenge in the herd.
Saige Zespy is a corresponding writer for the Wyoming Livestock Roundup. Send comments on this article to firstname.lastname@example.org.