By Russ Daly
Introduction
Transitioning a heifer calf into a productive, long-term member of the breeding herd requires attention to many important factors, including nutrition, genetic and breeding decisions, and environmental management. Disease and health challenges, however, can undermine all that work. Health issues can derail a heifer’s progress at every stage – from her own development to reproductive success, calving, and rebreeding.
The Heifer’s Ability to Stay Healthy
Disease problems, even early in life, can have lifelong effects on the breeding female. The most common of these, Bovine Respiratory Disease Complex (BRDC), might not seem like it has much to do with reproduction. However, evidence from the dairy world shows that heifers affected by BRDC as calves exhibit decreased survival to first calving, poorer calving scores, lower first lactation milk production, and a higher chance of leaving the herd after first calving due to the disease’s draining effect on immunity and other body systems.
Preventing BRDC needs to start well before the heifer is selected as a replacement. Vaccination for pathogens such as Infectious Bovine Rhinotracheitis (IBR, or “red nose”), Bovine Respiratory Syncytial Virus, Mannheimia hemolytica and Histophilus somni, should begin before weaning or earlier, with boosters as required by the vaccine. Close regular monitoring for illness and prompt treatment is important for every calf, but especially for potential replacement heifers. Paying attention to biosecurity concepts, particularly segregating feeder calves or other animals brought into the herd, will help prevent herd BRDC problems as well.
Examples of other diseases affecting heifer health include pinkeye and footrot. These conditions result in lower weight gains, poorer body condition scores, increased stress, and decreased mobility, all potentially detrimental to future fertility. Managing environmental factors such as flies and other eye irritants, and muddy lots are important, while pinkeye vaccination should be considered for heifers. For these diseases, prompt detection and treatment are critical to minimize their effects.
Internal and external parasites are also detrimental to overall heifer health and productivity; calves coming off pasture should be dewormed with an effective parasiticide.
The Heifer’s Ability to Become – and Stay – Pregnant
A heifer’s capacity to become – and stay – pregnant hinges on nutritional, hormonal, genetic, and immunologic factors all working together optimally. Lurking in the background, however, is the threat of infectious reproductive diseases. Of these infections, those caused by IBR and Bovine Viral Diarrhea Virus (BVDV) are especially important. Both can cause infertility and pregnancy loss; BVDV infections during pregnancy can result in calves born with birth defects or persistent BVDV infections. With their relatively inexperienced immune systems, heifers are at increased risk for these problems.
Source : sdstate.edu