When does a cow have the most nutritional needs? Before she calves, and after. That’s according to Bill Doig, regional livestock specialist at the University of Missouri Extension office in West Plains.
“When a cow is in her peak lactation,” he told Ozarks Farm & Neighbor, “which is approximately 30-90 days after she has calved, that is when she is needing the most nutritional components.” That’s due to the stresses of pregnancy and lactation; at the same time, he went on, “As a cow is in her last trimester of gestation – so, right before she calves – her nutritional needs are really increasing at a fast rate at that point as well.” Although there is, as Doig put it, “no magic formula” for computing a mama cow’s needs, there is a guide to help get you there. It’s "Nutrient Requirements of Beef Cattle," now in its seventh edition, a publication of the National Research Council.
Doig said a nutritionist will use the recommendations in this publication to formulate a diet, but he added, “There’s several different ways of doing this. You could take essentially the production cycle of the animal, which in the case of the animals that we’re talking about they’re in either the last trimester of gestation or they’re in peak lactation; or, we can look at their body weight.
We can also look at their body condition scoring, which essentially tells us how much fat cover does the animal have on it.” For instance, the book will tell you a cow with average lactation that’s two months past calving needs about 25 pounds of dry matter intake daily. But, “if you have cows that are lighter versus cows that are heavier in their weight and their body condition, then you want to adjust that.”
But Doig agreed the typical operator is not likely to break his cows down into many sub-feeding groups; the most they’ll typically do, he said, is put their spring calving animals in one group, and their fall calving animals in another. That means if a producer has a 90-day breeding season, there will be a significant difference in the needs of animals bred early in the season, from the needs of those bred near the end.
Depending on the time of year, the most likely need will be energy, and this can be met in a number of ways. Doig said you can utilize a high-protein feed source, “but most often when you’re feeding forages to the animal, whether it’s in the form of hay or perhaps spring pasture – or even stockpiled fescue-type pastures in the fall – you’re going to be fairly close on the protein requirements of that animal.” So, in addition to the condition of the animal – its stage of pregnancy, weight and body condition – the producer has to know the value of the feedstuff.
It’s essential to have forage tested, and to get information on grain supplements from the supplier. It’s also important to have cows in reasonable condition before they head into the last trimester of gestation. Otherwise, “it’s tough to get ahead of them at that point,” said Doig.
“The animal will start to lose weight; it’ll start to lose potential body condition.” That, in turn, will reduce lactation and the calf’s performance.
