How management, the environment and access to feed affect your herd’s milk production.
I visited a farm a while ago that had two dairy herds. One was in a tiestall barn and the other in a freestall barn. Both herds were managed by the same people, had similar days in milk and fed the same TMR.
The tiestall herd averaged 115 lb. of milk/cow/day while the free stall barn herd was 9 to 10 lb./cow/day lower.
The situation brought back memories of research by Alex Bach and co-workers in Spain on feeding the exact same TMR to 47 different dairy herds. After more than 8 months, milk production across the 47 herds ranged from 45 to 74 lb./cow/day.
Why the differences in milk productions when cows are fed the same ration? Management and the environment allow the cow to express the milk production potential of the ration fed.
Recent information on cow time budgets show a cow needs 4 to 5 hours per day for eating. During this time, she must have full access to the best feed, not in competition for feed, not standing at an empty bunk or trying to sort through already sorted feed.
Maintaining some feed in the bunk at all times (i.e. no empty bunk) was worth a plus 3.5 lb. of milk/cow/day in the Spanish research study. Pushing up feed more than once per day was a good return on labor and equipment with an average of 8.6 lb./cow/day more milk than those that did not push up feed.
Cows make milk while lying down and not standing up. Rick Grant and colleagues at the Miner Institute in New York found milk production could increase 2 to 3.5 lb./cow/day with one hour of additional lying time over a minimum requirement of about 12 hours per day. However, Dr. Cook and co-workers in Wisconsin have not found as direct a relationship between lying time and milk production and indicate high-producing cows are likely to stand ruminating a little more than low-producing cows.
There appears to be no advantage to under-stocking lactating cow pens, less than one cow per stall, and most likely a loss in milk production potential for the pen. Conversely, over-stocking up to 120% is done on many farms with no apparent loss in milk production.
Grant indicates 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 cow priority shifts from eating to resting. Immediate responses, such as limited or lowered milk production, are often not readily observed with overstocking, but increased lameness and poor foot health can become a problem with increased standing time.
As for the freestall and tiestall barns on the same farm that I visited, the freestalls were not overcrowded (115%) and feed was pushed up several times per day. The tiestall barn cows each had their own 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./cow/day in both barns.
The freestall cows 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 in the free stall housed cows.
The 9 to 10 lb. less milk production in the freestall-housed cows could be accounted for in feed energy shifted away milk production to greater activity and possibly thermal regulation.
This scenario illustrates an often-overlooked activity energy requirement of cows. With overcrowded pens, the activity energy requirement increases as cows look for feeding space and a stall to lie in, leaving less energy available for milk production.
JIM LINN is a dairy nutrition consultant and retired Extension nutrition specialist at the University of Minnesota–St. Paul. Contact him at firstname.lastname@example.org.