By Hubert J. Karreman, V.M.D.
One of the most sensitive times in a cow’s life is in the last couple weeks leading up to calving, when the body’s natural hormones are rapidly changing in preparation to deliver the newborn. For the dairy farmer, this of course means paying close attention to detail in the last two weeks before freshening, as well as observing proper calving procedures. If all goes well, a cow should calve on her own, drink five to fifteen gallons of water, get up, pass the placenta within four to six hours, start eating, and begin lactation. To have cows hit a decent peak and maintain persistence during lactation, good feeding and body condition is extremely important.
So we should think about the cow’s health prior to actually calving. Always have the animal at the farm where she is going to calve for the three weeks prior to actual calving. Do not transport her right around calving time. Her immune system isn’t very effective at this time to begin with, due to the internal stresses and hormones normally associated with calving, and the strain of transport only makes matters worse. I have seen way too many cows become critically ill when they are bought right at freshening time from a sales stable, and/or they actually calve-in on a cattle hauling truck. At three weeks before calving, we still have time to influence the cow’s immune system in a positive way, as indicated by the history of the farm. At this time you want to have the cow where she will be calving so that she will make the correct antibodies for her colostrum.
Colostrum can be positively affected by appropriate use of vaccination, if needed. Any vaccinations that you would like the calf to benefit from can be given to cows two to three weeks before freshening. You may want to vaccinate a cow with a coliform vaccine at this time in order to protect her from getting coliform mastitis when she is just fresh and, secondarily, to enrich the colostrum to protect the calf from deadly coliform scours in its first few weeks of life. If either of these two conditions occurs with some regularity on your farm, seriously consider vaccinating with J-5 or ScourGuard 4KC. If using these two specific products, you must also vaccinate the cow some three to four weeks earlier if it is the first time using it (like a few days prior to drying off). Annual boosters are also effective. For first-calf heifers (whose colostrum is never as enriched with antibodies as a mature cow), consider using a rota/corona vaccine or First Defense, a source of antibodies that can be given orally to newborns if scours in calves always seems to be a problem.
It’s also a good time to give MuSe (vitamin E and selenium), which has been scientifically shown to increase immune function, lower somatic cell count when fresh, increase fertility in the coming lactation, and reduce incidence of retained placenta. Retained placentas will unfortunately happen with hard calvings, twins, early calvings, and hypocalcemic (milk fever) cows even if you use MuSe beforehand, but if retained placentas are occurring other than at these times with any regularity, definitely check your selenium levels or simply use an injection of MuSe. These are cheap methods of insurance compared to the costs of lost production and vet bills associated with coliform mastitis treatment or retained placenta/metritis with a possible twisted stomach/displaced abomasum.
One of the biggest factors shown to hinder cows that are coming into third lactation or older is low blood levels of calcium (hypocalcemia/milk fever). This needs to be prevented at all costs as it is a major factor behind a cow not passing the placenta, becoming ketotic, and/or developing a displaced abomasum (twisted stomach). Studies have found that keeping potassium to less than 2.0 percent of the dry cow ration is important in preventing milk fever. Dry cows should not be fed calcium-rich or potassium-rich feeds such as alfalfa. Feeding grassy hay is a great way to accomplish this, but you still need to make sure the hay comes from areas that do not have high potassium in the soil. Grassy hays can indeed have higher amounts of potassium than recommended, especially on farms that have spent lots of money chemical fertilizer over the years in addition to spreading barn manure. In conventional systems, anionic salts are fed to counteract diets high in potassium and calcium; however, they are very unpalatable and need to be “hidden” in the TMR (total mixed ration). Small organic farms might not use TMRs as a feeding strategy and instead use component feeding (feeding each feed sequentially), so the anionic salts aren’t able to blend/hide among other feeds. Additionally, anionic salts may not be allowed by some organic certifiers. However, there is a very nice, natural alternative to anionic salts: apple cider vinegar. Feed apple cider vinegar at the rate of two ounces twice daily for two weeks prior to calving (remember the 2-2-2 rule). Apple cider vinegar is acetic acid, which gives off a negatively charged acetate ion, somewhat like the anionic salts. In general, relatively more negative ions (like sulfates) should be fed in during the dry period relative to positive ions (like calcium and potassium), whereas during lactation, relatively more calcium and potassium should be fed compared to the negative ions like sulfates. One interesting ion is magnesium (a positive ion). This should be around 3 percent of the dry cow ration and can be even higher. Magnesium is an incredibly important mineral nutrient for healthy muscles in general, balancing contraction and relaxation in an optimal way.
If severe edema is a problem, you have too many sources of sodium in your dry cow ration (sodium is also a positive ion). Do not give free-choice salt to dry cows, especially not to springing heifers, if udder edema has been an issue on the farm.
Consider teat dipping dry cows within two weeks of freshening twice daily since the keratin plug barriers at the teat ends are softening and environmental bacteria can start to enter the teat canal and cause mastitis. This is especially dangerous during the springtime as the bacteria in the cows’ bedding and environment seem to be “waking up” with the warmer temperatures.
Also, springing heifers should start being fed at least some of what the lactating cows are eating in terms of hay quality, ensiled feeds, and grain in order to have their rumen bugs adjust. Remember to avoid sudden changes in feed rations at all costs in dairy animals. It takes about two weeks for the rumen bugs to adjust to feed changes.
Okay, that’s the pre-game plan. But what about the day-of plan for actual calving?
First of all, try to gauge when a cow will likely freshen. Cows that are within two weeks of freshening need to be observed a few times daily for loosening of the ligaments near the vulva as well as general feed intake, especially in bull-bred herds when the exact breeding dates are not known. Additionally, cows diagnosed as possibly having twins should be watched especially carefully as they tend to calve one to two weeks earlier than the expected due date. Cows that are getting ready to calve will begin to eat less at about twelve hours prior to calving. The vulva will look somewhat fuller and looser as well. Milk may be dripping from the teats for a few days beforehand (definitely dip teats if dripping). Normal signs also include gradual “bagging-up” over a couple weeks’ time (udder enlarges) and a softening of the ligaments between the tail and pin bones.
Some older cows bag up real quickly right before calving. Beware: these older cows likely become milk fever cases. I’ve seen it often. This occurs because all of a sudden at calving the bones are called upon to release lots of calcium into the bloodstream, and they are simply not able to do so at the rate needed. Then the bloodstream calcium levels become very low and the older cow either gets a slow start or goes down with real milk fever. It is much better to see a cow “bag up” over a few weeks time because to give her bones time to adjust to releasing increasing amounts of calcium into the bloodstream instead of an instant demand right at calving time. Severe amounts of fluid accumulation in front of and in the udder in springing heifers are usually due to free-choice salt: getting too much and then drinking a lot of water and retaining it (due to the salt in the system). In these cases the suspensory ligament of the udder may rupture and the udder will forever be damaged. It may be good to use an udder bra/support on these animals (any lactation or age).
By the way, if the discharge is red at any time during pregnancy, the cow should be checked. If you see a red discharge near the time of calving, wash her up and reach in. A red discharge is a red flag that something is wrong. Do not wait. Get her checked the day you notice the red discharge. If a calf is dead, it needs to come out right away since they enlarge and get spongy as they decompose inside. Removal of an enlarged spongy dead calf is obviously more difficult, and the chances of a positive outcome for the cow decrease as time ticks away.
Source: Four Seasons Organic Cow Care