Mimic Nature (Where You Can)
When humans first domesticated animals, they began replacing natural living environments and animal behaviors with managed and controlled systems. And while today’s cattle breeds show little resemblance to their wild ancestors, scientists and producers find they still respond favorably to management and conditions that mimic nature wherever possible.
In its 2019 webinar series, the Dairy Cattle Welfare Council (DCWC) recently featured two dairy researchers outlined how dairies can facilitate cows’ natural instincts, balanced with economic considerations, in maternity pens and overall stocking rates.
Offer options in maternity pens
Ohio State University Dairy Scientist Katy Proudfoot, PhD, outlined how dairies might benefit by allowing close-up cows to express some of their natural preferences in where they deliver their calves.
Proudfoot, who researched the topic for her PhD program at the University of British Columbia and continues that effort at Ohio State, says cattle managers try to balance three aspects of animal welfare:
- Biological function.
- Affective state, meaning their response to psychological factors such as pain, fear or anxiety.
- Natural state, such as the animal’s preferences for particular environmental conditions and diet.
Most research in animal sciences has focused on biological function, Proudfoot says, with less known on the other two. So while we cannot directly compare modern cows with their wild relatives, researchers have conducted studies to identify their natural preferences and determine if encouraging those behaviors could benefit welfare and performance.
Proudfoot cites research from Sweden, where researchers observed groups of beef and dairy cows allowed to calve in large, open pastures. In this trial, 64% of pregnant cows isolated themselves from the herd to deliver their calves. The remainder chose to calve in a covered barn. Heifers tended to separate furthest from the herd, especially if they were disturbed by other cows. Cows generally sought out areas at higher elevations with tall grass and/or trees for their calving locations. Cows nearing parturition also tended to separate most from other pregnant cows, leading researchers to theorize the behavior results from the cow’s instinct to bond with her calf.
Dairies, Proudfoot says, generally use one of two systems for calving. One is to move cows to individual maternity pens at the beginning of calving. The other is to move close-up cows into group maternity pens. Each method has its advantages and challenges.
Individual pens provide more isolation from other cows, easier observation and easier clean-up between births. However, these pens often are located in high-traffic areas subject to human disturbance, and the timing can bring higher risk of calves delivered in the freestall or elsewhere.
Group pens require less human disturbance of cows and, because cows are moved earlier, less risk of calves born outside maternity pens. Cows in group pens however have less opportunity to seclude themselves, there is more risk of mis-mothering and the pens can be more difficult to keep clean with cows continuously rotating in and out.
Proudfoot has conducted several experiments to evaluate cow preferences for various calving environments. In one test, her team provided individual cows a choice between calving in the open or in a plywood-walled shelter within the individual pen. Among cows that calved during the daytime, 80% chose the shelter. For those calving at night, preference was evenly split between the two options.
The team also has compared the same system with pairs of cows in each pen, and found that the cow calving first was more likely to calve in the open than its pen mate.
Proudfoot acknowledges that shelters in individual maternity pens are not practical for most dairies, and the team currently is evaluating various options in group pens, such as providing more space per cow, providing barriers for isolation and limiting competition for those barriers.
The standard recommendation for 102 meters (1102 feet) per cow in group maternity pens probably is less than ideal, Proudfoot says, suggesting that providing 150 to 2002 feet allows better opportunities for cows to isolate themselves somewhat.
When the team provided six temporary barriers in pens holding 12 cows, they saw little difference in preferences. When they reduced competition by providing six barriers in pens holding six cows, they saw increased use of the barriers for calving.
For on-farm practicality, in addition to providing more space in group pens, Proudfoot suggests using some type of barrier to isolate individual or group pens from other activities in the barn. Some type of barriers inside group pens give cows a choice for more isolated calving if they want it. The group currently is testing the use of plastic water-filled road barriers for creating isolated shelters within pens. She also suggests using video cameras for observing cows in maternity pens to minimize direct human interaction during calving.
Seek balance in dairy stocking rates
Ideal stocking rates vary depending on facilities and management, and require a balance between cow well-being and economics.
Within limits, higher stocking rates can increase production while reducing fixed costs on a per-cow basis. At some point though, overstocking can negatively affect cattle welfare, feed intake, reproduction and productivity.
In another DCWC webinar, Dairy Scientist Rick Grant, PhD., President of the William H. Miner Agricultural Research Institute in New York, outlined research to determine the practical limits of overstocking, and at what level the law of diminishing returns takes over. Dairy producers, Grant says, often walk a fine line between stocking rates that benefit profitability and those that negatively affect health, welfare and performance.
Grant defines overcrowding based on three main parameters:
- Greater than one cow per headlock.
- Less than 60 cm (24 inches) of linear bunk space per cow.
- Less than one stall per cow.
Research has shown that about 58% of dairies provide less than 24 inches of bunk space and 43% use fewer than one stall per cow, Grant says.
Grant cites a Stall Stocking Density Calculator developed by dairy scientists at the University of Florida. The calculator allows the user to enter specific herd information including milk loss, conception rates, culling rates and milk and feed prices. In tests using a variety of scenarios, Grant says, the calculator indicates that 120% stocking rate is optimal for profitability. Maximum profit per stall occurs at greater than 100% stocking rate in 67% of the scenarios tested, and at greater than 120% in 42% of scenarios.
Grant describes excessive overstocking as a sub-clinical stressor in dairy herds. While not apparent through physical signs, sub-clinical stress leaves an animal less fit and able to respond to additional stressors. Farm-to-farm differences in response to overstocking, he adds, probably result from variation in other stressors present on farms.
Evaluation of stocking density, he says, requires understanding of how it affects natural cow behavior. On average, cows spend around 70 to 80% of their time either resting or feeding. They prioritize resting though, potentially at the expense of feeding time, and lying time decreases at higher stocking rates. Summarizing multiple studies, Grant says some show a linear decline in lying time as stocking density increases above 100%. Others do not show much decline until stocking reaches 120%, but virtually all the studies show declines in lying time as stocking rates exceed 120%. If stocking density does not affect lying time, he adds, performance is less likely to be affected.
Crowded cows can, he says, adjust their feeding behavior somewhat, but at some point, overstocking results in greater aggression and displacement, changes in time of eating, fewer meals and faster eating. Younger cows, he says, become more likely to fall behind due to competition at the bunk.
Stocking rate, and its influence on feeding behavior also affects the incidence of sub-acute ruminal acidosis. In fact, research has shown that the feeding environment affects rumen pH as much or even more than the diet itself.
Research has shown that primiparous cows in an overstocked situation experience greater declines in dry-matter intake than multiparous cows. In a 2012 study, researchers gave primiparous cows a choice of eating a low-palatability, low-quality feed with no competition at the bunk or a high-quality feed with competition for bunk space from an aggressive older cow. Most, Grant says, chose the low-palatability feed over competing. Other studies have shown declines in milk production, conception rates and pregnancy rates as crowding increases. In a 2008 trial, researchers saw steady increases in milk production as stalls per cow increased from 0.4 to 1.6. Research also has shown that the spread in milk production between primiparous and multiparous cows widens as stocking rates increase, indicating that younger cows suffer more from overcrowding in mixed-parity pens.
Also, Grant says, research has shown that herds with high de novo fatty acid synthesis are associated with greater bunk space per cow.
Ideally, for management and consumer perceptions, Grant says farms would provide one stall for every cow in a freestall barn. That’s probably not economically feasible in many cases though, and he says good management can allow some moderate overcrowding.
The ideal stocking rate varies depending on the management system, but Grant generally recommends the following:
- For lactating cows in four-row barns, keep stocking rates below 120%. In mixed-parity pens, stock at around 100% of capacity.
- For lactating cows in six-row pens, reduce stocking rates to closer to 100%.
- For close-up and fresh cows, stock at around 80% of bunk capacity, or about 30 inches of bunk per cow.
- Always allow adequate access to feed, water and stalls.
Grant concludes with these points:
- Optimal profit and cow well-being are achievable with outstanding management.
- With overcrowding acting as a sub-clinical stressor, the economic effects of cattle well-being vary widely between farms.
- We need to design facilities and manage cows in ways that optimize profit and well-being.
For related information on dairy facilities, cow welfare and production, see these articles from BovineVetOnline:
Lying Time Could Indicate the Health Status of Fresh Animals
Sanitation for calf scours prevention
