Benchmarking Herd Fertility Performance

CAFRE has published the first results from Fertility Benchmarking Online based on the fertility performance of 90 herds from across Northern Ireland for the 2005-06 breeding season.  These herds represent a range of production systems with autumn, spring or spread calving patterns and yields of 4,600 to 10,700 litres.

Fertility Benchmarking Online assesses heat detection efficiency, conception rate and overall herd fertility performance.  It also estimates the cost of herd infertility based on the cost of extended calving intervals (over 365 days) and the cost of replacing cows identified as non-pregnant at the end of the breeding season.  For the average herd this was estimated to be just over £18,000 per 100 cows.

With Fertility Benchmarking Online, first service submission rate is used as the main measure of heat detection efficiency.  This is the proportion of eligible cows served in a series of successive three week periods based on individual herd voluntary waiting period and breeding start date.  First service submission rate averaged 60 percent across the 90 herds benchmarked, but ranged from 43 to 79 percent between the bottom and top 25 percent of herds.

Analysis of the results established that the highest submission rates occurred in seasonal calving herds.  The autumn and spring calving herds had submission rates of over 70 percent demonstrating a strong focus on heat detection for a short period of time.  This is probably made easier through more cow to cow interaction with more cows being on heat at the one time, unlike spread calving pattern herds which had an average submission rate of 57 percent.

Across the 90 herds the average conception rate to first service based on pregnancy diagnosis was 53 percent.  This is higher than the 40 percent average reported by AFBI Hillsborough in 2003 where conception rates were calculated following subsequent calving.

Conception rates to first service ranged from 34 to 70 percent between the bottom and top 25 percent of herds.  Analysis of the results indicated that these were higher in spring calving herds (60 percent) than in autumn or spread calving herds (52 percent), possibly as a result of lower yields, less nutritional stress and the selection of cows with better fertility with infertile cows being culled.  

When herds were ranked according to yield, the top 25 percent of herds (average yield 8,700 litres) had lower conception rates (46 percent) than the remaining 75 percent of herds.  Similarly, herd size had a negative effect on conception rate with the largest 25 percent of herds (more than 120 cows) having an average conception rate of 44 percent.

Fertility Benchmarking Online uses a novel new method of assessing herd fertility performance – 100-day in-calf rate.  This assesses the proportion of cows intended for rebreeding that are back in calf again within 100 days of calving.  It gives a more accurate assessment of herd fertility than calving index which ignores cows culled for infertility.

On average, only 49 percent of cows intended for rebreeding were back in calf within 100 days of calving (100-day in-calf rate = 49 percent).  However, this ranged from 27 to 69 percent between the bottom and top 25 percent of herds.  The herds with the highest 100-day in-calf rates had higher submission and conception rates, but also tended to be lower yielding – mainly due to the influence of spring calving herds.

On average, the herd infertility cost for a 100-cow herd was estimated to be just over £18,000, but ranged from around £6,500 in the top 25 percent of herds to almost £38,000 in the bottom 25 percent of herds.  The total herd infertility cost in Fertility Benchmarking Online is based on projected calving interval and the cost of replacing cows potentially culled for infertility.  The cost of replacing cows potentially culled for infertility at the end of the breeding season is the biggest infertility cost.  This was estimated to be over £13,000 in the average herd but ranged from under £6,000 per 100 cows in the top 25 percent of herds to over £27,000 per 100 cows in the bottom 25 percent of herds.  In spread calving herds it is likely that some late calving or non-pregnant cows will be carried over for service in the next breeding season.  While these cows may not be culled, they have a longer calving interval and a prolonged interval to peak milk production in the next lactation.  This also carries an infertility cost with the loss of potential production ranging from £1.50 to £3 per cow per day beyond 365 days, depending on average herd yield.

Fertility Benchmarking Online is developed for use throughout the breeding season and can now be used to assess the fertility performance of your herd for the 2006-07 breeding season.  This service is available through the Rural Portal website (www.ruralni.gov.uk/fertilitybenchmarking) where fertility data for your herd can be manually entered using a secure online service.  Alternatively, it can be uploaded electronically using FarmWizard, Kingswood or Sum-IT/Agridata software.  Fertility Benchmarking allows you to assess the fertility performance of your herd against herds with a similar calving pattern.  If you want to find out more about Fertility Benchmarking Online, please contact your local Dairying Development Adviser or David Mackey at Greenmount Campus (028 9442 6861).

Fertility benchmarks for dairy herd performance in 2005-06 based on 100-day in-calf rate.