Securing optimal levels of winter milk performance in autumn calving cows requires a number of key management priorities to be addressed.
This is particularly the case during the dry period and the early weeks of their new lactation.
The all-important three weeks that lead-up to calving and the same length of time again at the beginning of the new lactation. This is known as the ‘transition period’.
United Feeds nutritionist, Jenny Hamilton, further explained: “Preparation for a cow’s next lactation starts as soon as she is confirmed back in calf. The all-important target is a body condition score of 2.75 to 3.0 at drying-off.
“Ensuring this is achieved entails the implementation of a specific and planned feeding regime and regular condition score monitoring throughout late lactation.
“Cows dried off during the late summer and early autumn period can be grazed initially. However, they should be brought indoors for the close-up period, three to four weeks before calving.
“During this period cows, and first-calving heifers should be offered highly palatable forages, which are low in potash and high in fibre.”
Winter milk performance
Palatability drives forage intakes, which is a key factor in determining a cow’s ability to increase milk output levels in the days and weeks directly after calving.
According to the United Feeds’ nutritionist, low potassium silages should be made from grass swards that have not received any slurry or fertiliser containing potash.
These forages should be fresh and palatable, free from moulds and available ad lib. They should also have a low Dietary Cation Anion Balance (DCAB) value.
Both cows and first-calving heifers should be placed on the same management regime during the all-important transition period.
Development work carried out by United Feeds has led to the formulation of bespoke dry cow management programmes that reflect the management conditions that prevail on Irish dairy farms.
Two fundamental points are now apparent – the need to offer cows and heifers specific pre-calver diets and the importance of feeding a pre-calver concentrate that helps meet the exact nutritional needs of these animals.
Hamilton continued: “A complex hormone mechanism controls calcium mobilisation from the bones and gut, requiring magnesium.
“To encourage calcium release we formulate a bespoke pre-calver ration to a strict mineral specification. This limits calcium and sodium intakes but increase the uptake of magnesium and phosphorus.
“The acid-base status of the cow also affects these hormone mechanisms. We include magnesium chloride not only to provide magnesium, but to slightly acidify the blood increasing calcium availability.
“Forages that are too high in potassium will act to reduce magnesium availability. The only way of truly ascertaining this information is to perform a forage mineral analysis.”
Winter milk performance
The close-up period is also a time when cows and heifers must receive optimal levels of all the key minerals, trace elements and vitamins to ensure a successful calving and a trouble-free start to the new lactation.
During the last three to four weeks of gestation, it is crucially important to maximise intakes, so as to ensure cows calve with a good appetite and a rumen well prepared for the lactating cow diet.
It is equally important to monitor cows closely in the three-week period post-calving. This assessment includes the regular checking of rumen fill in tandem with forage and concentrate intakes.
“Recording the temperature of cows seven days after calving is strongly advised,” Hamilton continued.
“Heightened temperatures are an indicator of disease and infections. A dairy cow’s normal rectal temperature is around 101°F or 38°C,” she said.
“Matching a cow’s nutritional intake, particularly energy, to milk output and ensuring good forage dry matter intake is also a priority during the early weeks of lactation.
“The animal should lose no more than one-half of a condition score unit between calving and subsequent breeding.
“Modern dairy cows are genetically programmed to produce milk. Matching this potential with the actual levels of output secured is, very much, energy driven,” Hamilton outlined.
