BUFFER FEEDING spring calvers in early lactation generates a cost-effective milk response and acts as a mineral carrier, believe Dave and Rachel Lee, who run a 250-cow herd in Shropshire.
It also helps first calvers maintain body condition and fertility, says Mr Lee of Winnington Green Farm, Shrewsbury. “We didn”t cull any heifers last year because they were barren,” he says.
“Targets are to serve 95% of cows in the first three weeks. Last year we served 260 out of 275 cows and heifers and 150 calved this season in the first three weeks.”
The crossbred herd still comprises 40% of the original Holsteins, but also contains New Zealand Friesians, Jersey crosses, Ayrshire and Swedish Red. Calving has been tightened from a January to June pattern four years ago, so that cows now calve from Feb 4 until mid-April, with 50% in milk by Feb 20.
While convinced that grazed grass is a far better feed than anything else, Mr Lee still feeds fresh calvers 4kg a day of compound, containing 14% crude protein and at least 13MJ of metabolisable energy/kg dry matter, in the parlour. Plus they have 4kg a head DM whole-crop wheat, with grazing to appetite – usually supplying a further 8kg DM a head.
“It is a grass management tool and it is quantity, quality grass that is crucial for fertility. But having always fed cows at spring grass, I would be loathe to stop. I don”t want to find out the hard way that it does have a benefit on fertility,” he admits.
Yields peak at 35 litres and total 5800 litres in a lactation. But by supplementing spring grazing, Mr Lee says he can push production to 6500 litres.
“The danger of cost cutting is that when production goes down too far, it increases other costs, as they are not diluted. Getting a 700-litre response with some inputs can be cost-effective because it dilutes fixed costs,” he says.
Dry cow diets are based on straw plus grass and whole-crop silages, with the silage portion increased towards calving. To control magnesium intake on heavy land and avoid staggers, cows calve indoors and are only turned out after 2-3 days when settled.
The compound acts as a mineral carrier for cal mag, says Mr Lee. Magnesium chloride flakes in the water provide a top-up at peak risk periods. Parlour compound is cut to 2kg a head in April and maintained throughout mating before being dropped gradually to just 0.1kg to bring cows in for milking. In total 500kg a cow are fed each year.
Similarly, whole-crop is used to balance grazing early and late in the season and eke out grass supplies. “We stop feeding it in mid-April, when grass growth outstrips demand, and start feeding again in the last round in October.
“We use it to maintain the length of the last round to keep cows out until November. It”s a struggle to get covers up high enough to 2600-2700kgof DM/ha. We also don”t want to graze down too tight and have no grass the next spring.”
A high cow stocking rate of 3.4/ha means the farm”s 12ha (30 acres) of whole-crop are grown on a neighbour”s farm, producing about 37t/ha (15t/acre).
“With 12 acres across a railway plus woodland, our farm”s effective area is just 170 acres. To maximise this, we use it as a milking platform and graze youngstock off farm.”
Spring Grazing Management
SLOWING SPRING grass down as it passes through the rumen helps bugs capture more of the nutrients, says independent consultant Bruce Woodacre. Spring grazing is high in protein but low in fibre, so it shoots straight through the cow”s digestive system. “Capturing more of the goodness in grass means cows milk better. They also maintain body condition, which is beneficial to fertility,” he says. Later in spring, cows can become energy deficient and the bugs lack energy to use ammonia produced by excess nitrogen in grass protein. “When ammonia isn”t used by rumen bugs, it”s turned into urea in the liver. But, on its way, it goes through all tissues. In the uterus, it affects sperm motility and embryo implantation.” He says the answer is to buffer grazing with starch and fibre. “This will mop up more protein so grazed grass is used more efficiently. Whole-crop or maize are ideal buffer feeds.”