The common feed bunk in dairy barns should be managed to get a consistent daily intake of nutritious feed into lactating cows. This practice stabilizes feed’s rate of passage and its fermentation/digestion in the cow’s rumen and lower digestive tract.
In turn, it ultimately meets the essential requirements of energy, protein, effective forage fibre, minerals and vitamins in order to support good milk and milk fat production.
Quite the opposite situation is also true: an empty feed-bunk often underlies poor health and performance issues in the lactating barn. Fortunately, its means of correction is straightforward.
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So, dairy producers should not ignore an empty feed bunk when cows are out of feed for several hours. That’s because dairy research demonstrates many metabolic changes occur within a cow’s body, when left hungry.
First, there is an interruption of feed fermentation that decreases the production/absorption of volatile fatty acids by 50 per cent. This lack of an important metabolite creates energy deficits at the cellular level, contributing to fresh-cow ketosis and a higher incidence of fatty liver and simply taking away from milk production.
On another dark path, it also interrupts the rumen’s ability to buffer lactic acids, which makes lactating cows more susceptible to digestive upsets.
Many of these problems are relatively invisible to most people, yet happen for some of the most unwarranted reasons:
- The producer wants the lactating cows to eat every last morsel.
- Not enough feed is provided on a dry matter basis.
- Feed is not pushed up enough times and remains out of reach for cows.
- Cows are heavily sorting the feed, which is pushed out of reach.
- The cows are not on a strict feeding timetable.
I have talked to several dairy producers about how they manage their lactating cows against running out of feed at any time of the day or night. Whether they milk their cows in a parlour-system or by robots is of little consequence.
Most of them recognize dairy cows are creatures of habit, who tend to go up to the feed bunk and/or waterers after they are milked, then lie down to ruminate what feed they just ate for several hours. Plus, the big question remains: if cows consume all their daily feed allotment, would they eat more, if more feed was provided, or would that contribute to leftovers usually given to the replacement heifers?
One of these producers (140 dairy cows) replied that he provides his cows feed three times per day. TMR is set down just before 4 a.m. and 3 p.m., when he milks them in his double-eight parlour. At 9 p.m., a nighttime feeding of chopped alfalfa-grass hay is unloaded in the bunk. Its purpose is just to fill up the cows during the night and assist with rumination. The feed is pushed up six times per day by skid-steer. This producer also takes a weekly moisture test of his daily TMR and calculates both ‘as fed’ and dry matter intake (DMI). Adjustments are made to the diet to maintain consistent DMI.
Another farmer milks 110 dairy cows, 100 km away, and has three robot milkers. He feeds 6,000 kilograms to those 110 cows in one 3 p.m. feeding.
A couple of months ago about 5,300 to 5,500 kg of TMR were fed per day, but that had to be adjusted upward due to a new bag of wetter corn silage. This producer wants no more than one to 1.5 per cent feed refusal, which still maintains some feed in the feed bunk, just before the next day’s afternoon feeding.
Plus, all feed is pushed up by a robot pusher every two hours during daylight hours and once or twice during the night.
I have been in both barns on several occasions and many cows are up at the feed bunk eating their fill. Plus, I look at the cows that are laying their stalls and they are ruminating without a care in the world. Others are loafing around in both free-stall lactation barns, with one or two under the rotary back-scratchers. Milk production in both barns is in the upper 30 litres with over four per cent milk fat.
Neither scene is replayed at one dairy producer I know, located several hundred kilometres away. His cows are fed twice a day but are frequently out of feed several hours after morning milking and not refurbished until about 2 p.m. (an hour before afternoon milking).
The funny thing is that his milk and milk fat production are similar to those of the two dairy producers examined above, but he has a higher proportion of skinny cows (body condition score less than 2.5), which I believe is related to a number of things as well as failure to keep a full feed bunk at all times.
