Photo by Michael P. King
The Van Os lab at UW-Madison
Understanding and promoting animal welfare is an essential part of achieving sustainability in food animal production. To this end, the applied research questions in our program follow these broad themes:
- Improving the fit between dairy animals and their environments: how do housing and management decisions affect physiology, behavior, and production?
- Understanding the needs of dairy animals from a biological perspective: what behaviors are important for them to be able to express and what resources do they need?
- Developing and validating tools: how do we evaluate animal welfare effectively on commercial operations? How can we use technology to help us monitor animal welfare?
Some of the current and ongoing research and extension projects in our lab include:
- Evaluating the cooling effectiveness of showering cows in the parlor during milking (with Dr. Mario Mondaca, Van Os lab graduate students Rekia Salter and Kim Reuscher, and data collection assistance from undergraduates Emma Eppig, Sky Sheng,Tiffany Feng, Amanda Gimenez, and Ashley Wagner)
- Evaluating ventilation system performance and cattle signs of heat stress in both naturally and mechanically ventilated barns, including extension education on assessment techniques for producers, vets, and consultants (with Drs. Mario Mondaca and Nigel Cook)
- The effects of teat and bucket feeding of both milk and starter on the performance and behavior of individually and pair-housed calves reared in outdoor hutches (Masters thesis of Rekia Salter)
- Interactions between social housing and thermal comfort (in heat- and cold-stress conditions) of calves reared in outdoor hutches, as well as calf preferences for ventilated vs. non-ventilated hutch microenvironments (Masters thesis of Kim Reuscher)
- Understanding nutrient partitioning and social competition to improve genomic selection for feed efficiency in dairy cattle (PhD dissertation of Faith Baier, with Drs. Kent Weigel and Heather White)
- Development of a novel biosensor to combat heat stress in dairy cattle using multi-modal real-time sensing and machine learning (undergraduate Sky Sheng and graduate student Kim Reuscher, in collaboration with graduate student Hanwook Chung and Drs. Younghyun Kim, Chris Choi, and Sabrina Brounts)
Previous work by Dr. Van Os
Postdoctoral Research at UBC
As a postdoctoral fellow with the Animal Welfare Program at UBC, Dr. Van Os worked with Drs. Nina von Keserlingk and Dan Weary. The projects she was involved with included:
- Describing the use of non-rotating grooming brushes by weaned dairy heifers (with undergraduate honors student Savannah Goldstein)
- Improving the transition of weaned dairy heifers from open-pack to freestall lying areas (with Savannah Goldstein and visiting undergraduate Jessica St-Pierre)
- Understanding the factors that contribute to dairy cattle defecating while lying down (led by visiting doctoral student Livia Mangilli from the lab of Jose Fregonesi)
- Evaluating the effects of sample size on misclassification of dairy farms according to various welfare standards (with João Costa and Maria Hötzel)
Postdoctoral Research at UC Davis
In 2016, Dr. Van Os worked as a postdoctoral scholar in the lab of Dr. Cassandra Tucker at UC Davis, where her research topics included:
- Effect of muddy ground conditions on dairy cattle lying behavior, cleanliness, and physiological responses (with Carolyn Stull and David Ledgerwood)
- Motivation of feedlot cattle to obtain forage when fed a high-energy, low-roughage diet (with Trevor DeVries and Erin Mintline)
- Individual differences in behavioral responses of feedlot cattle to novel feed items (with Trevor DeVries and Erin Mintline)
- Comparison of data collection methodologies (instantaneous sampling vs. continuous observation) for capturing dairy cow behavior in freestall housing (with Karin Schütz)
- Evaluation of sample sizes and sample-selection strategies for determining the prevalence of welfare indicators on commercial dairy farms (with Christoph Winckler, Terry Lehenbauer, John Champagne, Soraia Matarazzo, and Julia Trieb)
Dissertation Research at UC Davis
Dr. Van Os’ Ph.D. research at UC Davis focused on balancing dairy cow comfort in hot weather against potable water use.
Dairy cows are vulnerable to overheating in summer, and spraying them with water is an effective way to cool them. But, cattle respond to sprinklers in variable ways. Across studies, responses range from voluntarily using this resource to avoiding getting wet, particularly on the head.
Understanding behavior matters because you can lead a
horse cow to water, but you can’t make her drink get wet. Most dairy cows in the U.S. are housed in systems that allow them to choose when to use sprinklers. So this means cows’ usage of sprinklers may determine both how well they are cooled and how much potable water is wasted.
Sprinkler flow rate (amount of water over time) is one aspect that determines both how well sprinklers cool cows and the impact with which spray lands on cattle. Higher-flow sprinklers may be better for reducing body temperature and increasing milk yield, but generate greater impact, which cows may avoid. For my dissertation research, I conducted several studies to investigate the effects of sprinkler flow rate on dairy cow behavior, physiology, and production.
Dr. Van Os found that cows avoided exposing their heads to higher-flow spray, but did not avoid using it overall. Higher-flow sprinklers also cooled cows more effectively, but with a pattern of diminishing returns. Above a certain amount of water (1.3 liters/minute per nozzle, applied for 3 minutes), there were no differences in body temperature or milk yield. This research showed that in a hot, dry, climate, there may be potential to save water when cooling cows.