Why challenge heifers to calf at 14 months and how do you know they are ready?

“We've been hitting this key since 2011, it's been almost a decade”, said veterinarian Leonardo Souza, managing partner of Qualitas Genetic Improvement, about the need to impregnate females at 14 months.

“We have already begun to understand, in fact, that this is the way to improve the productivity of the calf. There is no other strategy that increases the productivity of the offspring more than impregnating the female at 14 months . We have already proven that, with the same number of females in a calf herd, it is possible to produce more than 30% more calves ! So there's no other technology, no other tool, let's think like this, that can increase the productivity of the calf as much as the pregnancy at 14 months”, defended Souza.


The veterinarian also informed which indicator the rancher can observe to know if he is ready for the challenge of precocinhas. “First the breeder feels in his herd that he has the ' heifers left over '. What do we call a leftover heifer? This is the main point. Staff impregnate females usually around 300 kg at two years of age. If that's still your case, producer, don't try to handle pregnancy at 14 months. You are not ready because your females are not 'left over'. Your females are left over when they are 400, 450 kg at 24 months of age to get pregnant. If you have this reality on your farm, you are advanced in the process of both genetics and nutritional management of your herd, you are ready to start this process. So I think that maybe the best recipe I can pass on to a producer so that he doesn't start mistakenly on his farm would be to really have his heifers left over”, pointed out Leonardo.

As revealed by the specialist, with heifers reaching 300 kg at 14 months , it is possible to challenge them to participate in the breeding season. But to reach this level of maturity, the breeder needs to “prepare the ground” from the moment these heifers are conceived.

“We have also verified the following: calves, in general, including this female, have to be born in good times. What are good times? They are arriving now. Now, in the months of August and September, are the months where the best calves on the farm will be born – and also the best calves. So the first step is to concentrate the birth of your calves that will become matrices that will become pregnant at 14 months at the best time of the year. So that we can do this, we create a breeding season that allows births at the best time of the year and, above all, that the breeding season is short, so that we have the largest number of calves being born at this time. When you do that, automatically we will have the first phase being attended, which would be weaning a calf around 200 kg of weight”, he calculated.


Once the calf is weaned at 200 kg, it becomes a serious candidate for breeding before 14 months, as the veterinarian explained. “If you weaned a calf weighing 200 kg, you need to add another 100 kg to her so that she reaches 300 kg when she is 14 months old to start mating. This is a simplified protocol of the process. Weaning a heifer weighing 200 kg so that it weighs 300 kg at the time of pregnancy , insemination, because the history that we have in the Qualitas herd for a decade has shown that with this female weighing 300 kg at 14 months, within a breeding season of 70 days , you will be able to impregnate over 80% of them. Point. The recipe is given ”, summarized Souza.

Leonardo reinforced the importance of nutritional conditions so that genetics can be expressed and enable a good chance of pregnancy at 14 months. According to the expert, there are even many producers who try the challenge in a particular crop end up abandoning the attempt the following year because they understand that they are not yet ready.

For the veterinarian, the journey is even longer for the Nellore , as the Angus , for example, has a greater selection history for sexual precocity . “It's a huge challenge, but it needs to be done,” said the vet. In addition to genetic selection for precocity, nutrition reinforcement, the breeder must be careful to keep females with good maternal ability , good amount of milk in his herd, so that in addition to impregnating, she gives good conditions to her calves. The bulls selected to breed these heifers must also have characteristics for calving ease , as calves cannot be born too large due to the smaller size of the dams.

More than guaranteeing the first precocious pregnancy, Leonardo informed that, in order to be as productive as possible, a sow must have weaned three calves over 200 kg with up to 60 months.

“The main reason is actually a focus on financial results, on economic results. Why does the female have to wean three calves over 200 kg up to 60 months of age, actually up to four and a half years or, at most, five years? Because this female will leave more money on the farm compared to a female who left only two cubs. And not only that – the biggest cost that exists in the breeding phase is precisely the cost of rearing females that are unproductive. […] Regardless of when she becomes pregnant, it will cost at least R$ 3,200.00 today on a farm. To give birth to the first calf, it cost more than R$ 3,000.00. He's a mathematician!”, he exposed. Hence the importance of spreading this cost over more calves weaned throughout their productive life.

Asked if there is still time to prepare the matrix that is not well nourished for the next breeding season, Leonardo Souza was emphatic. “Unfortunately for this breeder, the year is over!”, he lamented. In order to be able to start breeding, the female, as the veterinarian taught, must have given birth to her last fat calf, with a good score, to arrive with reservations at this moment before the breeding season, when the pastures are dry and the corn, which could help with this body score, is expensive.

Even so, Souza believes that, especially in 2020, many females that shouldn’t still enter the breeding season due to calf appreciation, so at weaning of the crop conceived this season, in 2022, the “batch”, on average, will have worse quality.

The veterinarian concluded his interview with Giro do Boi by summarizing the tips for good reproductive management. “If you want to have a highly productive breeding farm, make a short breeding season , at the right time of year , that you will harvest fruits that you didn't believe was possible to have on your farm. The first thing that will change is that you will have calves weaned on your farm from 250 to 300 kilos , which you have not seen before”, he concluded.

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