Page 309 - The Welfare of Cattle

286 the WeLfare of CattLe

Mortality

Several studies have shown that the mortality risk was reduced when cows had access to pas-
ture. Thomsen et al. (2006) found the mortality risk reduced in Danish herds for cows during the
first 100 days of lactation that had access to pasture during the summer compared to continuous
confinement (OR = 0.78). Burow et al. (2011) compared 131 Danish herds using summer grazing to
260 herd identified as zero-grazing herds. The risk of cows dying was 4.8% vs. 6.0% (p = 0.11) in
grazing herds compared to zero-grazing herds, a 46% reduction in grazing herd compared to zero-
grazing herds.

Summary of the Meta-analysis Studies on Comparison of Pasture to Confinement

The meta-analysis showed an improvement in the cow health in a reduction of lameness in cows
that access to pasture compared to continuous confinement. Other aspects of cow health were not as
apparent. Whenever possible, it appears desirable to give cows access to pasture even when part of
the life-cycle includes confinement.
The fourth of the five freedoms is the expression of normal behavior by providing sufficient
space, proper facilities and company of the animal’s own kind. At face value this seems like a
fairly straight forward means of comparing the cow’s preference for one environment over another
as a viable means of evaluating preference in expression of normal behavior. There are numerous
factors that confound what seems to a fairly straight forward comparison. Few studies have directly
compared dairy cow behavior of cows on pasture-based systems to cows in a continuously housed
in a confinement environment. Most of the studies that have that have made comparisons were done
a number of years ago. The comparisons do not split out dairies where the cows in confinement
have access to an outside dry lot. The understanding of the effect of stall design and bedding mate-
rials and stall surface relative cow comfort have improved over time. In addition to cow comfort,
environmental and management factors affect the prevalence of lameness. Access to pasture and
depth of bedding explained 50% of the variation in clinical lameness in NE and California dairy
herds (Chapinal, 2013). When Canadian researchers offered cows a choice between pasture and free
stalls with Total Mixed Ration (TMR) indoors, cows spent 54% of their time on pasture, mostly
during the night time (Legrand, 2009) preferring the confinement during the day. In addition to stall
design, dairies in areas of the country with climatic heat stress have implemented various means of
cow cooling and improved ventilation to mitigate heat stress and improve cow comfort. Because of
the potential extreme stress in the desert southwest, dairies have had develop sophisticated meth-
ods of cooling cows to attain high levels of milk production. Some dairies developed systems with
bedded packs to provide good cow comfort. The surface on which cows walk affects cow comfort.
Some dairies have implemented rubber mats in high cow traffic areas and along feed alleys to
improve cow comfort.
However, there are a large range of factors affecting cow comfort in confinement facilities.
These include heat abatement and ventilation, surface on which the cows walk, free stall design,
bedding materials, and space allocation. Climate has a profound effect on animal preferences as
result of extremes in temperature and moisture. Depending on latitude in the US, northern states
have winter conditions which are not suitable for being outside in the winter month. In southern
latitudes, summer may provide enough heat stress that cattle will seek means of shelter from the sun
and heat abatement when available. I have seen cattle run from the milking parlor to cooling ponds
in the summer on Texas dairies to mitigate heat stress. Rainy weather may result in muddy condi-
tion in the traffic areas between milk parlor and pasture. Nutrition will be different between pasture
and confinement. Cows on pasture are primarily limited to the nutrient content of the grasses. In
confinement facilities, TMRs are the most common means of feeding dairy cattle which will tend