What happens in the maternity pen, does not stay in the maternity pen. Rather, the events and environment there can impact a newborn calf for the rest of its life, particularly when it comes to respiratory disease.
Because lung damage in calfhood can impact lifelong health and performance, researchers at the University of California-Davis conducted a multi-phase, large-scale population study examining various management factors and their influence on calfhood bovine respiratory disease (BRD).
On a recent episode of the “Have You Herd?” podcast from the American Association of Bovine Practitioners, Dr. Sherif Aly, veterinarian and epidemiologist at the UC-Davis Veterinary Medical Teaching and Research Center at Tulare, Calif., discussed the results.
Aly said the first portion of the study was a survey with more than 40 questions issued to dairies throughout California that helped narrow down the management factors that affect BRD. The next phase, dubbed the “BRD 100” study, drilled deeper into those issues on 104 cooperating dairies. Finally, the resulting information led to the “BRD 10K” study, which gathered health and performance data on more than 11,000 calves from birth to weaning on 5 dairies located in the 3 major milksheds in California.
In that study, management practices were assessed by risk factors that contributed to BRD in varying degrees. A score of 1.0 or higher indicated a risk factor. Of particular interest was the maternity pen, where the following risk factors were identified:
(1) Cows and heifers calving together – Commingling first-calf heifers in the same maternity areas as multiparous cows resulted in a BRD offspring risk factor of 1.4, meaning there would be a 40% greater likelihood of calves contracting BRD.
(2) Bedding changes – Changing the maternity pen bedding 6, 7, or 8 times per month significantly reduced the risk of calves contracting BRD. Interestingly, changing the bedding 9 times per month actually produced an uptick in BRD risk to calves.
(3) Bedding materials – Compared to dried manure solids mixed with gypsum, both dirt and plant-based bedding materials (rice hulls, almond hulls, straw, and wood shavings) showed higher risk factors for BRD. Dirt had a whopping 4X odds ratio compared to a manure solids/gypsum base.
(4) Pasture calving – Calving on pasture produced a higher risk factor for BRD compared to enclosed maternity pens.
(5) Dam separation – Removing calves from their dams within 1 hour of birth produced a significant reduction in BRD risk.
The study also examined the association of BRD incidence related to herd demographics, colostrum delivery, vaccination, nutrition, and housing.
Aly said BRD is a complex, multi-factorial disease, lamenting that the incidence in dairy calves has not improved significantly over several decades. His team’s work revealed that 22-23% of calves contract BRD in the preweaning period, which leaves much room for improvement.
By drilling deep into the management practices and related BRD incidence on California dairies, Aly is hopeful the data and knowledge gleaned from their work can help dairies reduce their struggle with the disease. “BRD in preweaning period sets the stage for the success of these cows later on in life,” he declared.
