DAIRYING MANAGEMENT NUTRITION: Monitoring Intake Is Key to Yield Increase
WITH increasing genetic merit, cows yielding over 35 litres are common in many commercial herds. To produce this amount of milk a cow needs over 250 megajoules (MJ) of energy/day to meet her requirements for maintenance and milk production.
A cow calving down in fit condition score 3.0 can afford to lose weight at up to 0.5kg/day during early lactation without significantly affecting health or fertility. Allowing for the energy provided from this tissue loss, a 35 litre cow will still need to obtain approximately 240MJ of energy from her feed.
Many of this year's first-cut silages are around 20 per cent dry matter (DM) and with an ME below 11.3MJ/kg DM. Typical freshweight intakes of 50-55kg of such silage will provide 110-125MJ of energy.
High quality concentrates, with a dry matter ME of at least 12.6MJ/kg, need to be fed at a rate of 10-11kg/day in order to meet these energy requirements. A total dry matter intake of over 20kg/day is required in this situation. Monitoring intakes becomes ever more important as yields increase. Your local Greenmount College Dairying Development Adviser can assist you to check the adequacy of your rations.
To ensure your cows are not being underfed, check silage intakes and dry matter. The DM of silage fed from an open silo pit after several days' rain could be 4-5 per cent lower than indicated by a cored sample taken for analysis last autumn. The difference between feeding 50kg of an 18 per cent DM 11.3 ME silage and 50kg of a 22 per cent DM sample of similar energy content is over 22MJ of energy.
This equates to almost 2kg of concentrates, 0.8kg/day of weight loss, or four litres of milk! Where silage quality is poor and/or intakes low, a protected fat such as Megalac can be added to the concentrate to boost energy intakes.
At an inclusion rate of 35kg/tonne, the energy content of 10kg of the concentrate will be lifted by over 8MJ - sufficient to produce over 1.5 litres of milk.
THREE TIMES PER DAY MILKING
Consideration should be given to three times per day milking, if the herd is of high genetic merit, labour is available for night milking, and the economic climate is correct. The influence of Holstein breeding has improved genetic merit substantially in recent years. Younger cows and first calving heifers have more milking potential than is currently achieved in many systems. It is these animals in early lactation, and high genetic merit cows in late lactation, which express the greatest response to three times per day milking. Response can vary from 5 to 15 per cent, more commonly a 10 per cent increase in bulk yield is achieved.
If feeding meal through the parlour, total feed is spread over three feeds which can reduce digestive related disorders and improve general cow health.
Less stress on high yielding animals, which leads to less udder wear and reduced somatic cell count. …