Today’s economic downturn requires a long-term perspective and a focus on efficiency in modern dairy operation systems.
Raising quality replacement dairy heifers provides an excellent opportunity for improving genetic potential, supporting the producer’s prospect goals and the dairy’s profitability. Exceptional management is essential to raising healthy calves.
This area has generally been neglected in large production facilities. As external, contracted calf ranches become more popular, the dairy still plays a fundamental role in the survivability, health and future value of replacement heifers through management at the close-up period, calving and in the first hours after birth.
Immunity starts prepartum
Increasingly, dairy producers are focusing on the close-up period largely to reduce the impact of metabolic disorders in postpartum. Calf mortality is closely related to the dam’s health during gestation. Specialized nutrition in the last 30 to 45 days pre-calving has also been proven to contribute to calf health. Essential minerals, such as vitamin E, fed and subsequently stored by the cow during the close-up period, improve the immune system response and are easily transferred to the neonate via colostrum.
The age of the cow and vaccination program, as well as the natural exposure to pathogens, is usually positively correlated with the colostrum quality, measured by antibody level.
Maternity management and newborn care
Septicemia is one of the most important causes of early mortality in dairy calves. Assuring a clean, disinfected environment reduces exposure to infectious disease organisms and is crucial for the health of the cow and the newborn. Immediately after birth, navel dipping with a solution of 7 percent iodine is imperative as the umbilical cord represents a direct pathway for bacteria to the calf’s circulatory system.
The calf’s acquired immunity
At birth, the calf is born with a rather immature defense mechanism due to the inability of antibody transfer via placenta from the dam. The role of colostrum in the first hours after birth is imperative and determines the calf’s future survivability, health and performance in its productive life. Colostrum is defined as the first mammary secretion after calving and differs largely from milk due to the higher concentration in solids and most importantly immunoglobulins (IgG), representing the first line of defense to disease in the newborn calf.
Colostrum management and passive transfer
Proper quantity, quality and timing at the first feeding are critical to assure a successful transfer of IgG into the bloodstream. Calves should obtain between 10 and 15 percent of their bodyweight at the first feeding. A second feeding of first-milking colostrum of the same amount should be given within 12 hours after birth.
High-quality colostrum should be administrated as promptly as possible after birth. The ability of the immature cells in the small intestine to absorb large molecules, such as IgG, is greater in the first hour and decreases dramatically, ceasing at 24 hours after birth. In addition, in the first 12 hours, the digestive system is deprived from functional enzymes that otherwise would compromise IgG integrity and function.
It’s important to understand that at this stage, the immature cells of the intestine wall do not distinguish large molecules as bacteria that are attempting to enter the bloodstream. Providing colostrum immediately after birth and reducing the potential bacteria load presented initially to this system is crucial.
Measuring colostrum-deprived calves for large dairies
High mortality and morbidity rates are costly to the dairy industry. Herds experiencing severe losses in calves less than two weeks of age should determine if colostrum deprivation is a problem. Identification of the calf’s antibody absorption status can help determine how to define a preventative treatment plan for colostrum-deprived calves. An accepted procedure for large dairies is the quantification of total serum proteins.
Calves containing less than 5 grams per 100 milliliters indicate insufficient colostral antibody absorption and proactive assistance measures should immediately be taken.
Nutrition support can help
Appropriate nutrition plays an important role in stimulating the immune system and a proper intestinal microbial balance, assuring maximum health and performance. Nutraceuticals have been shown to actively reduce the amount of pathogens in the small intestine, contributing to improved health and enhanced nutrient absorption.
More recently, commercially available sources of nucleotides included in yeast cytoplasm have been added to calves’ diets to stimulate the initial development of the intestinal vilae, promoting absorption capacity in the early stages of a calf’s life.
• Proper calf and heifer raising represent an increased opportunity for improved efficiency in commercial dairy operations.
• A proactive nutrition and vaccination strategy contribute to enhancing the immune status of the cow and the transfer of nutrients and IgG to calves at birth via colostrum.
• Colostrum feeding time is critically important due to the short-term absorption of large molecules and potential bacteria colonization of the intestine.
• Nutrition should support the immune system of both cow and calf, improving the response to disease challenges and promoting the overall profitability of today’s dairy operations. PD