Calf scours is a management disease. After all, proper management will keep the incidence of scours at a minimum, although it may be impossible to completely avoid the problem.
Nutrition, stress and infection influence the development of scours. However, a balanced ration, stress reducing management practices and a planned vaccination program can control scour development.
The most important practice to minimize scour problems in calves is providing adequate nutrition to the cow. This helps ensure a strong, live, healthy calf and allows her to produce high-quality colostrum to nourish and protect the calf.
Colostrum varies in nutrient quality and antibody levels due to a number of factors. The antibody levels generally increase as the cow ages to about 7 years and gradually declines. First-calf heifers usually have both lesser quantity and lesser quality of colostrum.
The antibody level in the first milking after calving is higher than in subsequent milkings. Nutrient quality also declines after the first milking. The nutritive value of colostrum is often overlooked as an important factor in calf survival.
Solids and fat levels are twice as high in colostrum compared to regular milk. Total protein is more than four times as high with most of that due to the 65-fold increase in immunoglobulins, which are proteins. Many trace minerals and vitamins also are more concentrated in colostrum.
Nutrients provided by colostrum also stimulate activity and growth of the digestive tract. Consumption of colostrum causes an increase in the secretion of hormones in the gut. These hormones influence growth, secretion and motility of the developing intestinal tract.
One concept that's not stressed enough is the effect of calving difficulty or dystocia on the newborn. This is especially important in first-calf heifers in which a majority of births may be difficult.
Calves from cows born after dystocia often suffer from respiratory acidosis and oxygen deprivation. These acidotic calves are less efficient at absorbing colostral antibodies.
Coupled with a longer lag time before the dystocia calf gets up and nurses, thus delaying colostrum intake, dystocia is a major reason for high mortality rates of calves from first-calf heifers.
Brown Adipose Tissue
In the newborn calf there are two types of adipose tissue — white and brown. The primary purpose of white adipose tissue is to be used as energy storage and the release of fatty acids for use as an energy source. However, brown adipose tissue (BAT) is used exclusively for the generation of heat through non-shivering thermogenesis.
Though BAT accounts for just 1.5-2% of body weight in the newborn, it can account for 40-50% of thermogenesis in the newborn while the balance is due to shivering thermogenesis.
The amount of BAT produced in the fetus may be influenced by feeding the cow supplemental fat. Research by Bob Bellows, Miles City, MT, indicates calves from cows receiving supplemental fat in late gestation had a higher body temperature in response to cold weather.
These calves from cows fed supplemental fat also were able to maintain that temperature longer than calves from cows on a low-fat diet. The reason is that these calves had more glucose available for metabolism and heat production and possibly more BAT.
Interestingly, pregnancy rates were greater for cows receiving fat supplementation, even though the supplementation stopped at calving. This indicates a carry-over effect from the supplementation.
In Wyoming research with pregnant cows fed 50-65% of recommended energy levels, 90% of the calves survived birth and only 71% survived to weaning. Calves from cows fed recommended energy levels had 100% calf survival at birth and to weaning.
Calving is the most critical time and the most complex time in a calf's life.
Achieving early and adequate intake of high-quality colostrum in the calf is the single most important management factor in determining calf health and survival. We must be prepared long before calving to ensure that we have a live, healthy calf that will survive beyond weaning.
David Wieland is a nutrition consultant specializing in cow/calf, feedlot and horses. Based in Shepherd, MT, he also publishes a subscription newsletter. For more information, contact him at 406/373-5512 or e-mail at firstname.lastname@example.org.