Early Lactation
Every stage of lactation presents different challenges when it comes to feeding dairy cows. This is particularly so in the last three weeks prior to calving and first three months after calving - the early lactation period.
Changes in feed intake and cow condition
After calving, dairy cows undergo a distinct lag in feed intake capacity compared to energy demand to support lactation. This is known as negative energy balance and it can typically last up to three months. As a result, cows lose weight and body condition in the first months of lactation which must be restored in mid to late lactation.
Excessive loss of body condition in early lactation leads to poor reproductive performance and therefore needs to be carefully managed. The target herd average body condition scores at calving should be 5.0 and no less than 4.5 at two weeks before the mating start date.
Nutrient recommendations
Given the lag in feed intake capacity during early lactation, the energy density of a cow’s diet is crucial to supporting milk production while limiting the loss of body condition. A target energy density of 11.5 to 12.0 megajoules of metabolisable energy per kilogram of feed dry matter (MJ ME/kg DM) is desirable. Total metabolisable energy intake should be 190 to 240 megajoules per day (see table below) for a typical Australian dairy cow in early lactation producing 6,000 to 8,000 litres per lactation (26 to 34 litres of milk per day).
A typical dairy cow also needs 1,600 to 2,100 grams per day of metabolisable protein. Unlike the metabolisable energy content of a feed, the metabolisable protein content of a feed cannot be found on any given feed lab report. Instead, metabolisable protein supply and demand needs to be calculated through consideration of the crude protein content of the diet, the rumen degradability of the crude protein, the level of feed intake, the type of energy sources fed and a number of other factors.
Nutrient recommendations for early lactation cows
| Nutrient | Target in early lactation | ||||
|---|---|---|---|---|---|
Metabolisable energy (MJ/day) |
190 to 240 |
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Energy density (MJ ME/kg Feed DM) |
11.5 to 12.0 |
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Crude protein % |
16 to 19 |
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Metabolisable protein (grams per day) |
1600 to 2100 |
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Neutral detergent fibre (NDF) |
28% to 32% |
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Physically effective NDF (% of total NDF) |
70 to 75 |
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Starch % |
18-24* |
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Sugar % |
6-8 |
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Crude fat % |
4-5 |
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Calcium % |
0.8-1.0 |
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Phosphorus % |
0.4 |
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Magnesium % |
0.3 |
*Safe starch levels vary inversely with the speed of starch degradability. Dairy farmers should seek advice from a nutritionist if unsure about the optimum level.
