Digital Dermatitis in Replacement Heifers: A “Life Sentence?” – Floyd Sutton, Zinpro
Raising replacements is an important part of a successful dairy operation. Reaching adequate size at first calving between 22 and 24 months of age is an achievable goal and one that helps optimize profitable milk production. A properly balanced ration, including vitamins and minerals, provides essential building blocks heifers need for physical development, healthy calving, and a higher lifetime milk production. Trace minerals are essential to develop a strong immune system and reproductive tract, maintain skin and claw integrity, and thus boost the animal’s ability to perform and resist disease.
One of the biggest challenges in heifers is controlling digital dermatitis (DD). This infectious skin disease is often seen in heifers starting around puberty. Heifers that develop DD in the growing period are often given a “life sentence” because of the nature of the disease and the difficulty to treat chronic lesions once they establish in the animal.
Recent research examined the impacts of DD on performance in the first lactation. This study looked at a group of 719 heifers at six months pre-calving. They were fed two different trace mineral programs; the control group received a common sulfate trace mineral program and the treatment received a combination of sulfates and metal amino trace mineral complexes. Heifers were monitored for DD and classified into three types at calving. Type 1 heifers never got a wart, Type 2 heifers had one incident, and Type 3 heifers had two or more treatments. The heifers were followed through first lactation and monitored for milk production, hoof health and reproduction.
Heifers with one or multiple DD events between breeding and calving were at greater risk for DD in first lactation; 45.6 percent and 67 percent, respectively, versus 13.7 percent for the Type 1 heifers. The study also showed a very strong correlation between reproduction and DD type. Compared with heifers that experienced no DD prior to calving, the heifers that had multiple treatments during rearing had decreases in first-service conception rates (29 percent versus 42 percent) and an increase in days open (157 vs 132).
Production was also significantly lower during first lactation with just one incident in the pre-calving period. Heifers with one incident lost 439 pounds in first lactation and heifers with more than one treatment lost 738 pounds. In addition, independent of DD incidence, heifers on the complex trace mineral program produced 423 pounds more milk than the heifers on the control.
As we learn more about how DD infects and spreads through a herd, it becomes clear that a disease prevention and control strategy can be successful when started early in an animal’s life. Effective control strategies include three important components:
- Management must enforce biosecurity principles to keep infected animals from entering the herd. Regular inspection of heifers for early DD lesions and prompt treatment will reduce the chronic lesions, which become a source of further infections.
- A clean, dry environment and the use of footbaths, as needed, reduces stress on the skin to prevent infections. Additional manure removal and reduced crowding can often have very positive impacts on leg hygiene.
- Nutrition can play a key role in preventing DD during all growth phases. Nutrition can be part of a prevention strategy that provides benefits later in the cow’s productive life.
To reduce DD in our lactating herds, we must focus on the source, which often is the heifers. With good feeding and improved prevention strategies, we can reduce DD in both groups and have a healthier, more productive herd.
Starting Strong - Calf Care