Benefits of Pregnancy Diagnosis
Dr David Mackey, Dairying Technologist, Greenmount Campus, CAFRE
Turnout is widely talked about at this time of year, but fertility should not be forgotten about when the cows go to grass. For spring-calving herds, it is time to start breeding, but for the majority of dairy farmers with autumn/winter calving, turnout is an important milestone in the breeding season. Most herds are about two-thirds the way through the breeding season, and pregnancy diagnosis is useful for identification of pregnant cows and assessing fertility performance to date.
Pregnancy diagnosis has a number of benefits. As expected, its first role is to assess the pregnancy status of cows that have been bred. More importantly, pregnancy diagnosis should identify cows that are not pregnant. So what about these non-pregnant cows? While your vet is with you, it is a good chance to have them checked out and, if required, give them appropriate treatment. If still intended for breeding they should not be forgotten about – write their numbers down on a list and continue to check them at least three times a day for signs of heat.
Pregnancy diagnosis is a key tool in fertility management, particularly at this time of year when it is useful to know which cows still aren’t in calf. Traditionally vets used rectal palpation, but modern ultrasound technology means that pregnancy diagnosis can now be conducted much more accurately as early as 30 days after service, and can even allow the developing foetus to be aged if a service was not recorded.
Ultrasound scanning also has other roles in general fertility management. It can be used to assess whether or not cows are cycling at the beginning of the breeding season, and help identify problems earlier. Research has shown that the incidence of delayed return to normal oestrous cycles and ovarian problems such as cystic ovaries has increased over the years. Therefore, many farmers realise the benefit of having their vet out to scan cows routinely, perhaps every 2-4 weeks throughout the breeding season, allowing them to react much earlier to fertility problems in individual problem cows.
Pregnancy diagnosis is useful when it comes to planning ahead, as it can help you to:
- Manage nutrition for the remainder of the lactation.
- Assess number of replacement heifers required.
- Plan vaccination programmes.
- Plan for possible batching of animals.
- Plan drying off dates in advance of calving – particularly important for choosing the correct dry cow antibiotic.
These issues are all addressed as part of the very successful Dairy Herd Fertility Challenge delivered by local DARD/CAFRE Dairying Development Advisers throughout Northern Ireland. To date, around 450 farmers have taken part in this programme. Fertility Benchmarking Online is a further development by CAFRE which will be available soon through the Rural Portal website. This will allow farmers to assess the fertility performance of their herd and benchmark it against that of other herds of similar type throughout Northern Ireland. For further information on Fertility Benchmarking Online, e-mail the fertility benchmarking team at fertilitybenchmarking.greenmount@dardni.gov.uk or contact David Mackey at Greenmount (Tel: 028 9442 6861).
David Mackey, Dairying Technologist, with Jim Fulton and Michael Graham after reviewing fertility performance of the Greenmount herd following turnout to grass.