How good are your submission rates
John Wilkinson Dairying Development Adviser CAFRE (Dungannon)
Heat detection is critical to achieving good fertility performance in the dairy herd. Calculating the submission rate for your herd can assess the efficiency of heat detection. This is the proportion of cows eligible for service, and intended for rebreeding that have been seen on heat, and served for the first time during a three-week period.
| Submission rate = | Number cows served during a 3 week period | x 100 |
| Number of cows eligible for service |
Most farmers do not serve a cow until she is calved at least 6-8 weeks. This period is known as the voluntary waiting period. Cows intended for rebreeding become eligible for breeding, after this period of time.
A WORKED EXAMPLE
If the breeding season starts on 1 February and the voluntary waiting period is six weeks, only cows calved more than six weeks (on or before 21 December) are eligible for service during the first service period (1 to 21 Feb). If twelve cows calved before this date of which two are not intended for rebreeding, the number of eligible cows is 10. If seven of these cows are served the submission rate is 7/10 x 100= 70 percent.
This exercise can be repeated for each three week breeding period, based on cows eligible for their first service only.
A submission rate significantly below the target of 80 percent will give an early indication of fertility problems.
IMPROVING SUBMISSION RATES
A good recording system
- Cows must be clearly identified, preferably freeze branding.
- All systems should record cow number, calving date, all heats and services and include brief comments regarding calving difficulty, health, and pregnancy diagnosis. Cows should be listed in calving date order
Good records makes it easier to prepare action lists by identifying cows which were in heat three weeks previously and are potentially due on heat again. Problem cows that are not cycling, or repeat breeding, can also be identified.
Know when cows are more likely to show signs of heat.
- An adequate diet (including minerals and vitamins) to avoid excessive loss of condition in early lactation.
- Are cows in good general health, vaccinated against infectious diseases and with a minimal level of lameness
- Suitably housed with a spacious loafing area and a nonslip surface to encourage mounting activity
- In close proximity to a penned bull.
Heat detection techniques
- Ideally cows should be observed for signs of heat three times daily for up to thirty minutes each time.
- The best times to observe cows are early in the morning (before milking) before the evening milking and late at night
- Cows are reluctant to show signs of heat at milking or feeding time
Since not all cows will be observed in standing heat it is important to look out for secondary signs of heat. These include: -
- Head mounting and chin resting
- Restleness and bellowing
- Reduced appetite and milk yield
- Eating when other cows are resting
- Bloody mucous, after heat.
Use of heat detection aids
- Tail paint, pressure strips or electronic mount detectors, all indicate that the cow has been mounted and may be in heat.
- Pedometers are devices attached to the cow’s leg to monitor activity. Increased activity indicates that the cow may be in heat.
- Vasectomised bulls incapable of breeding have proved very successful. They should be fitted with a chin ball marker (these are also very useful for breeding bulls). It is important to remember that teaser bulls may be aggressive and should be treated accordingly.
- Milk progesterone testing kits can be used to identify when progesterone levels are low thereby indicating that the cow may be in heat.
All of the above topics are covered in the Dairy Herd Fertility Challenge programme. Many have already found this locally delivered programme beneficial. Contact your CAFRE Dairying Development Adviser for details.
Some of the members of the Caledon Dairy Herd Fertility Challenge who recently spent an evening calculating their herd submission rates. Sam Thompson, Senior Dairying Development Adviser (front right) has been facilitating the group.