Dairy Notes January 2012
Managing winter rations
Successful dairy cow feeding involves achieving the best possible balance between a number of key nutritional, practical and financial factors. Continual assessment and adjustment of diets is necessary to ensure your cows are fed correctly. Some key areas to monitor include:
- Bulk milk tank volumes to determine daily yield.
- Feed intake to help assess actual consumption of nutrients.
- Body condition score which provides a good measure of cow’s energy balance.
- Dung consistency, if firm and forms mounds this suggests the diet is low in protein or high in fibre. If loose and thin this suggests excess protein, low fibre or acidosis.
Practical feeding considerations
Provided it is well managed, using a feeder wagon to produce a Total Mixed Ration (TMR) can produce a significant increase in feed utilisation compared to feeding blocks of silage and concentrates twice daily in the parlour. There should also be less digestive and metabolic problems, and milk production usually increases. However,if the ration is not balanced correctly and monitored, TMR can be an expensive feeding system, especially if the milking cows are all run as one group.
Providing a single TMR for the whole herd, which has been formulated to provide balanced nutrition for the top 25 percent yielding cows in the herd will undoubtedly over supply the remaining 75 percent. Such a feeding policy could be expensive this winter with many herds having more stale cows milking January to April, as a result of poor fertility with last year’s spring calvers. Overfeeding could also mean a number of these cows putting on too much condition, leading to calving difficulties and low appetite/excessive weight loss after calving.
To ensure stale cows and the avoidance of lower yielders being overfed, set the concentrate level in the TMR to meet the lowest reasonable yield in the group. In-parlour feeding can be used to offer up to 5 kg of concentrates at each milking, supplying sufficient energy to produce up to 22 litres of milk. If the top 10 percent of cows in your herd are producing 45-50 litres, you could adjust the TMR to provide for Maintenance (M) plus 28 litres with the rest of the cows concentrate requirement being fed in the parlour. Stale cows would still be overfed although not as severely when compared to being fed a TMR for M plus 35 litres. The ideal option is to run a second group for stale cows and low yielders.
Farm energy costs - the vacuum pump
Milking parlour vacuum pumps have enough capacity to cope with the largest possible anticipated demand. This demand usually occurs when the parlour is washing or when a cluster drops of a cow causing air to be drawn into the system. A vacuum on demand pump matches pump speed to the actual air in the system, modulating the speed and energy consumption of the motor to match the actual vacuum needed. Some manufactures claim between 40 to 65 percent energy savings by adding vacuum on demand system to your vacuum pump.
Some theoretical figures for a 5KW vacuum pump fitted with vacuum on demand system running six hours per day.
·Energy consumption - 10,950KWh.
- Running cost - £1,095 per year.
- Vacuum on demand system installed £3,000.
- 50 percent energy savings.
- New energy consumption - 5,475KWh.
- Cost saving - £547 per year.
- Payback - 5.4 years.
Each farm will be different depending on vacuum pump size and milking duration. Some manufactures insist on installing a new vacuum pump which will double the installation figure quoted above.
A vacuum pump fitted with vacuum on demand system
