Dairy notes January 2009
Fertility Management
Results from Fertility Benchmarking Online confirm that heat detection is a major problem on farms with an average of only 63 percent of cows being served within 21 days of becoming eligible for service.
The two key elements to successful heat detection are clear cow identification and an effective system of keeping breeding records. Ear-tags are difficult to read at a distance due to their small size and often a covering of dirt. Freeze branding with large digits allows a cow to be easily identified. Previous records of heats and services can be used to anticipate future heat and prompt closer observation for heat activity three weeks later.
A number of computer based herd management packages can generate action lists of cows expected to come on heat. These systems can be accessed and up-dated by PDA or mobile phone, making information readily available in the yard as well as the office. A combination of a paper based record with details of all calvings, heats and services along with a pocket diary or breeding board allowing anticipation of heats can be just as effective provided information is kept up to date.
Cows on standing heat for only short periods and pressure on farmers' time to devote to heat detection has made the adoption of heat detection aids more important. Aids to be considered include:
- 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.
- A Teaser bull: 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 cows which he has mounted.
- 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 a cow is in 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.
- If you are planning new housing facilities, consider provision of a loafing area with non-slip floor to encourage mounting activity. If a bull is to be used consider housing him close to this area.
Service Management
Most of the proven semen used to produce herd replacements is in ‘dose critical’ straws – the straw contains the minimum amount of semen needed to give acceptable conception rates. You can’t afford to kill off a lot of the sperm by poor handling :
- Know where the straw you want to use is in the tank by maintaining an accurate semen location chart. Then you will not have to lift out a straw to check if it is the one you want or worse still wipe the frost off with your finger to read the name – all exposure to heat will kill sperm.
- To ensure as many sperm as possible are reactivated use a thermometer to check the water in the thawing container is between 33 and 39 degrees Celsius
- For DIYAI users, it is advised to attend a refresher course every three to four years, to have your technique assessed and obtain advice on where improvements can be made. Contact your semen supplier to arrange training.
