Dairy Notes March 2010
Heat detection
Could you benefit from the use of heat detection aids to improve herd fertility? With two to three months of the breeding season over, a check of your herds breeding records will show you how effective your heat detection has been. In most herds the aim is to serve cows on the first heat observed after they have been calved 42 days (voluntary waiting period). In an ideal world this would mean all cows would have a service recorded within 63 days of calving. Allowing for health problems, difficult calvings etc. a realistic target is to have 80 percent of eligible cows served within 63 days of calving.
Go through your breeding records now and check how many cows were served within 21 days of completing the voluntary waiting period. If the figure is less than 65 percent you need to take action.
Cows now spend less time on standing heat, and pressure on time to devote to heat detection has made the adoption of heat detection aids more important. Aids to consider include:
Tail paint – an aid to heat detection
- Tail paint, pressure strips (for example Kamar or Bovine Beacon) or electronic mount detectors which are glued to the tail head. Any of these systems will indicate if a cow has been mounted and may have been on heat. This system can be put in place rapidly and provide benefits for the rest of the season.
- Motion monitors. These devices are attached to the cow’s leg (pedometer) or around her neck to record activity such as walking or head movements. An increase in activity from her normal pattern will indicate that she is most likely to be on heat. The monitors can be integrated with existing parlour software and auto ID systems or provided as a stand alone package with its own reader to identify stock as they enter the parlour. This system will take a few days/weeks to set-up.
- A teaser bull. To ensure the animal is not fertile the operation needs to be carried out by a veterinary surgeon several weeks before the vasectomised animal is turned into the herd. This is an option for next season or when cows go to grass. Vasectomised bulls have proven useful but they retain the aggression of a fertile bull so careful management is required. They should be fitted with a chin ball marker to help identify the cows which have been mounted.
Parlour maintenance
Milking parlours should be tested and serviced at least twice a year – it is false economy not to. High vacuum levels, incorrect pulsation, over-milking and worn liners are some of the more common problems. When identified they are easy to correct.
Many farmers replace liners themselves, but are they replaced as often as they should be? The majority of rubber teat liners are expected to last for 2500 milkings or six months, whichever comes first.
Remember liners are the only piece of equipment which is in direct contact with the cows’ teats twice a day, 365 days per year. As the liners become worn they lose their tension and shape. This increases milking time which can cause teat damage and poor milking out leading to a rise in cell count.
Research at Moorepark indicates that liners should be replaced after 2000 milkings. Liner life in days = 2000 x number of milking units divided by number of cows x number of milkings per day. For someone milking 120 cows twice a day through a twelve-point parlour, the liner life in days would be 2000 x 12 divided by 120 x 2 = 100 days.
If liners are not replaced on time milk yield drops by about 5 percent. The cost of replacing the liners in this twelve point parlour is about £180. If the 120 cows are averaging 27 litres per head per day, a 5 percent yield loss would cost the herd almost £40 per day in milk sales – it would only take five days of reduced herd yield to cover the cost of the liners.
Do your liners need replacing?
