Good DMI Is Key To Milk Production – for Sep. 6, 2010

On any given day, dairy producers should know how much feed lactating cows are eating.

The key to filling the milk bulk tank is finding ways to promote good consistent feed consumption, because there is no substitute for good dry matter intake (DMI) when it comes to producing milk. The first rule of milk production is simple; the more essential nutrients, a cow receives, the more milk she produces. Therefore, producers should do what they can when putting a highly nutritious and balanced ration in front of the cows and manage it properly to maximize consistent feed intake.

One of the first things producers might do before adjusting rations is to be aware of the natural dynamic forces of consumption in a lactating dairy herd. High milk-producing cows during early lactation should be on target to consume 3.5 to four per cent of bodyweight in dry matter feed, each day. Maximizing DMI at this time sets the tone for the rest of the lactation; for every extra kilo of DMI a cow eats at peak milk production yields an extra two to 2.5 kilos of milk per day until she is dried off.

Most peak mature cows will consume 22 to 25 kg of dry matter feed at this time. Smaller and growing first-calf heifers should eat 21 to 22 kilos on a dry feed basis. Meanwhile, dairy cows will only eat so much “as is” feed, because its moisture content adds simple bulk to the dairy diet. Early-lactation mature cows consume about 43 to 45 kilos of feed, while younger and smaller cows often eat no more than 40 to 43 kilos of the same diet. By keeping such DMI and “as fed” values in mind, one can predict how much total ration to feed the herd on a daily basis; monitoring how many old and young early-lactating cows are entering the herd, as well as counting the remainder of the herd milking in mid-and late lactation.

From this valuable information, provide a balanced ration with all the essential nutrients in a tidy “dry matter package” (which also accounts for “as fed” feedings), so nutrient requirements for good milk production are matched for all lactation stages. Even though, one may find, at the high milk production targets, the range of feasible lactation diets might become limited. All workable diets are still based upon the same primary dietary principles when compared to other modest production goals, one of which is good, palatable forages of optimum quality should be fed.

Consumption of good-quality forages by lactating cows sets the foundation of good milk production. High-quality forages with adequate digestible or “effective” fibre and other essential nutrients supports a “catch-22” situation: healthy rumen fermentation leads to greater DMI, and vice versa.

Top milk-producing cows, consuming high amounts of feed, often spend between four to six hours eating and another six to eight hours, ruminating or “chewing their cud.” Cud chewing is a good sign enough digestible “effective fibre” is being fed and rumen fermentation is digesting the feed properly; turning it into high volumes of milk. It is commonly recommended at least 50 per cent of cows, when lying in stalls, should be chewing their cud.

In contrast, low-quality forages, high in acid detergent fibre (ADF) and neutral detergent fibre (NDF), have poor nutrient digestibility, which will limit feed intake, respectively. Likewise, mould and mycotoxins contamination of poorly harvested and stored forages will adversely impact overall feeding rates.

Likewise, moisture content of forages has a major impact on the total DMI of the dairy diet, particularly when ensiled forages are very wet, such as when adding silage or haylage to the daily TMR. High-moisture forages; those feedstuffs of less than 30 per cent dry matter content, will not only reduce the diet’s concentration of milk-making nutrients and lower forage digestibility by the rumen microbes, but adds unnecessary bulk to the ration. When this problem occurs, producers can substitute more dry hay in place of the wet feed. This corrective action dries the whole feed mix toward a more desirable 50 per cent dry matter content, which not only promotes DMI, but retains the much needed fibre level of the diet for good rumen health.

Similar tools of improving DMI of a well-balanced formulated dairy diet include:

Sustain a good forage base or concentrate ratio of 60:40 to promote good rumen digestion.

Diets should maintain a minimum NDF level of 27 to 30 per cent and 75 to 80 per cent of that minimum, forage related. Non-structural carbohydrates (contains the starch) should be limited to 35 to 37 per cent of the diet.

Keep the feedbunks full with fresh feed. Avoid “empty bunk syndrome” by feeding fresh feed two to three or more times daily, and push up ration to the cows throughout the day.

Do not wait for the cows to eat every morsel of diet from the previous feeding before putting down new feed. A three to five per cent feed refusal rate is normal.

Test dairy diets on occasion for dry matter content. It might be necessary to either reformulate the daily diet or make adjustments to the overall amount fed.

Place low-moisture molasses lick tubs supplements or free-choice sodium bicarbonate in loafing area in order to help buffer rumen fluids in cows consuming high-energy diets.

Avoid feeding excessive levels of unsaturated fats such as high levels of vegetable oils (over 0.75 lbs./head/day) or substitute with rumen-protected “bypass fats.”

Provide free access to fresh, clean water, because good water intake promotes good feed consumption.

Set up a special close-up cow diet. Dairy cows consuming a transition diet (three weeks before calving) or about 12 kg of dry feed daily have been shown to have greater DMI in early lactation and less fresh cow metabolic problems.

PeterVittiisanindependentlivestock nutritionistandconsultantbasedinWinnipeg. Toreachhimcall204-254-7497orbyemailat [email protected]

About the author

Columnist

Peter Vitti is an independent livestock nutritionist and consultant based in Winnipeg. To reach him call 204-254-7497 or by email at [email protected]

Comments

explore

Stories from our other publications