Management and the environment allow the cows to express their full milk production potential.
By Jim Linn, dairy nutrition consultant
I visited a farm a while ago that had two dairy herds. One was housed in a tie-stall barn and the other in a freestall barn. Both herds were managed by the same people, had similar days in milk and were fed the same total mixed ration (TMR).
The tie-stall herd averaged 115 lb. of milk per cow per day while the freestall barn herd was 9 lb. to 10 lb. per cow per day lower.
Why the difference in milk production when cows are fed the same ration? Management and the environment allow the cows to express their full milk production potential.
Cow time budgets show a cow needs four to five hours per day for eating. During this time, she must have full access to the best feed, not be in competition for feed, not standing at an empty bunk or trying to sort through already sorted feed.
In the winter, cows in freestalls will likely divert additional energy supplies for activity and maintenance.
Cows make milk while lying down, not standing up. Rick Grant and colleagues at the Miner Institute in New York found milk production could increase 2 lb. to 3.5 lb. per cow per day with one hour of additional lying time, over a minimum requirement of about 12 hours per day.
However, Nigel Cook and researchers at the University of Wisconsin have not found as direct of a relationship between lying time and milk production. They indicate high producing cows stand ruminating a little longer than low producing cows.
Understocking lactating cow pens, by less than one cow per stall, offers no apparent advantage. It most likely results in a loss in milk production for the pen. Conversely, overstocking to 120% is done on many farms with no apparent loss in milk production.
Grant says the effects of inadequate lying time are much more pronounced when stocking density of the pen exceeds 120%. Lying times for cows occupying a stall may actually increase in excessively overstocked pens as the cow shifts priority from eating to resting.
As for the freestall and tie-stall barns on the same farm that I visited, the freestalls were not overcrowded (115%), and feed was pushed up several times per day. The cows in the tie-stall barn each had a well-maintained stall, feed was always in front of them, and they did not have to leave the stall to be milked. Average dry matter intake was about 57 lb. per cow per day in both barns.
Cows housed in the freestall were more active in walking to the bunk to eat and to the parlor for milking. It also was winter, which required more thermal energy.
The 9-lb. to 10-lb. loss in milk production in freestall-housed cows was likely due to energy shifted away from milk production to greater activity and thermal regulation.