By Hubert J. Karreman, V.M.D.
It is common knowledge that cows grazing well-managed pastures will have dramatically fewer general health problems, and especially less digestion problems since they are eating what they were created to eat. The key to fewer health problems, of course, is well-managed pastures. Yet young stock, those around the time of weaning and then placed out on pasture, are a slightly different story. As everyone is well aware, young stock six months of age and older must also be eating at least 30 percent dry matter on average from pasture during the entire grazing season. We thus need to balance the environment and nutrition of these more delicate animals before being placed on pasture so they do not succumb to common problems that adult animals tend to fend off better.
A lot depends on how strong the calves are as they are weaned and shortly thereafter. Weaning time is extremely stressful for the calves, regardless of how they were given milk: from an individual bottle in a hutch or if they have been running freely with nurse cows. Weaning may be more stressful to calves having been on nurse cows, but those calves tend to be more robust as well. There are good points and bad points to everything.
Unlike drying off a cow abruptly to get the best results by stopping the brain’s signal to make milk, weaning should be done as gradually as possible to avoid stressing calves, especially upsetting their digestion. Prior to weaning, your calves should already be eating all the kinds of feed that they soon will be completely reliant on. They should already be used to the forage and grain. Their rumens are functional prior to weaning time, and having forage as part of the feeding routine enhances health of the rumen by keeping a fiber mat for the calves to chew cud, which provides saliva and sodium bicarbonate to help keep the rumen pH at about 6.8, where it should be for the best internal environment for the microbes that live in there. A healthy mat of fiber in the rumen also helps to slow down the rate of passage of feed in general.
Calves fed only grain and milk as pre-weaned animals (a feeding method conjured up by academic research in the 1990s and most likely funded by grain company money) tend to have more digestive upsets and may even experience rumen acidosis, which can affect their ankles and hooves for the rest of their lives (see this by strong pink areas at the ankle). This is a terrible condition at any age but even worse in an animal so young.
Another stress to calves is dehorning/disbudding. Hopefully everyone is now using the portable burners on a regular, periodic basis for different sets of growing calves and not using choppers as a caveman would use on older calves. Using a burner is much, much less stressful than the choppers and also leaves no blood at all, which reduces the attraction for flies and their wiggling, burrowing maggot offspring that can inhabit the chopped site. Make sure when burning that there is a copper-colored ring at the base of the horn bud, usually after seen about five to ten seconds when the burner is good and hot. Do not flick off the now dead horn cap, it will fall off over a couple weeks time. If you do force it off, it could cause bleeding. Still, disbudding even with a burner is stressful and should be done well before weaning, ideally at about one to two months old, and with lidocaine for anesthesia. This of course means you are not weaning until three months old. Do not dehorn (by any method) at the time of weaning or shortly thereafter. Always give a good solid week before weaning. I’ve seen too many instances when calves are weaned and dehorned during crummy damp weather and the stressed animals come down with pneumonia.
It’s not rocket-science to realize that a cow’s milk is meant for her offspring calf. The biological signal for peak milk production of dairy cows starts to decrease at two to three months into lactation. Once the calves reach three months of age or older they need less milk and rely mainly on solid food. Calves will naturally be stronger the longer they are on milk, which will translate into animals that can weather the common problems that occur when they are weaned and put on pasture. But with the current grazing requirements for animals six months of age and older, you now have to tend to this group of animals in regards to pasture management almost as closely as your milking cows.
IT’S NOT ROCKET-SCIENCE TO REALIZE THAT A COW’S MILK IS MEANT FOR HER OFFSPRING CALF. The biological signal for peak milk production of dairy cows starts to decrease at two to three months into lactation.— Hubert J. Karreman, V.M.D., Four-Seasons Organic Cow Care
By rearing a healthy, robust calf, underlying problems such as low levels of parasites encountered on pasture will not be quite as much of an issue. You need to be aware that as you put calves out on pasture in the summer, there are stomach worm larvae waiting there to meet them from the last season if young stock were out there the last grazing season. As the warmth and humidity of spring and summer go on, the stomach worm larvae population will increase dramatically, so you really need to make sure that calves are receiving proper levels of energy, protein and minerals for their immune systems to mature quickly enough while the animals are encountering these pests for the first time. A young local farmer had a fantastic idea of putting the young animals on the pasture for a few days and then take them away for about a month, and then put them on it for real. Without realizing it, the young farmer was applying a concept of vaccination in a very natural way: expose an animal to a low amount of challenge, withdraw for three weeks for the immune system to process the incoming information, and then reexpose the animal to trigger the immune system to the fullest.
If calves born in February through April and weaned three months later are sent out back to the same paddock where such groups of animals always go, they will quickly become infested with internal stomach worms since they have no natural immunity to them. Typical signs of infestation include pot-bellied calves with obvious angularity to observable bones, a rough-looking and reddish-black coat, with diarrhea and dried manure on thin back legs. Animals in the age group between one month after weaning up to about ten to twelve months old are the most likely to become infested. Once past this age, they tend to have enough wherewithal to build a solid, natural immunity that will be with them for life. See chapter 10 for more information on parasites.
If any part of their nutritional needs is not met, however, even the best calves will start to look worse and worse over the course of the pasture season. I have seen this occur way too often over the years. But to be fair I have also seen really nice calves their first season on pasture, if they are fed properly and the pasture is managed such that it is not a wasteland of rank forage growth with more weeds than actual forage.
Source: Four-Seasons Organic Cow Care