Farm Ireland
Independent.ie

Tuesday 6 December 2016

Several ways to detect if cows are prepared for AI

Dr Dan Ryan

Published 30/11/2010 | 05:00

Ultrasonography or scanning is an excellent tool to determine if cows are fit for AI, as shown by Dr Dan Ryan. This technology, operated by a competent individual, will inform you which cows are cycling, their current stage of the heat cycle, and if fertility impairing uterine infections are present
Ultrasonography or scanning is an excellent tool to determine if cows are fit for AI, as shown by Dr Dan Ryan. This technology, operated by a competent individual, will inform you which cows are cycling, their current stage of the heat cycle, and if fertility impairing uterine infections are present

Farmers need to start breeding cows now for September calving next year, but many have delayed this because of poor profit margins from winter milk production.

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This may be short sighted, because the last thing you want is empty cows. To avoid this scenario, you will need to focus on a concentrated breeding period up to Christmas with the aim of AIing all eligible cows.

What's an eligible cow? Some farmers may feel that cows should be greater than 60 days calved before breeding. I believe that all cows calved greater than 40 days are eligible for AI at the end of the first three weeks of breeding. The most practical way to keep a handle on this is to list all cows that are eligible for AI numerically on a chart and place it in a prominent position in the milking parlour.

Cows need to be fit to achieve high submission and pregnancy rates. The fitness of your cows is determined by management of two key periods, namely the drying off and early post-calving times.

Cows should ideally achieve a body condition score (BCS) of 3-3.5 at drying off, which should be maintained until they calve.

The next challenge is to keep the cow's plumbing healthy after calving. The repair of the reproductive tract post calving (uterine involution) is dependent on several factors; dry cow management, calving difficulty and diet management in the first two weeks post-calving.

The target submission rate should be close to 90pc. This means detecting nine out of every 10 fit cows in a 21-day period of heat detection. Heat detection indoors requires a lot of attention to detail. Cows need space and good underfoot conditions to express signs of heat. Access to an outdoor pad will encourage expression of signs of heat. Farmers do not generally use tail paint as an aid to heat detection indoors. Vasectomised bulls with chin ball markers work well outdoors but are more prone to injury indoors. A more recent development in heat detection at farm level has been the use of technology, which monitors the movement of cows.

An example of the latter is the Moo Monitor. This measures the amount of activity by cows and relays it to a central station. This alerts the farmer with a text message to those cows ready for AI. The technology has been perfected by Dairymaster so that the cows for AI are separated using drafting gates after the relevant milking. However, this technology will only work if the cows are fit for breeding. Environmental stressors such as lameness, hock injuries, over crowding, poor light, poor diet management and housing environment will all impair the expression of heat signs.

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Ultrasonography or scanning is an excellent tool to determine if cows are fit for AI. This technology, operated by a competent individual, will inform you which cows are cycling, their current stage of the heat cycle, and if fertility impairing uterine infections are present.

Environmental stressors described above affect the structure of the reproductive tract and can be determined from ultrasonography images. This information can be used by the farmer to determine his fittest cows for AI. If you have not detected cows in heat prior to breeding or within the first three weeks of breeding, book a visit now for scanning to identify why cows have not been submitted for AI. Each heat missed is costing your business in excess of €100.

Having bred the cows, you need to ensure the uterine environment will not be hostile to the embryo which enters about four days after AI. It is hard to believe that events going back to condition score at drying off could have a bearing on pregnancy outcome. But that is exactly what is happening here.

The embryo hatches around seven days after AI. It then elongates like a 'baby in a blanket'. The elongated embryo must produce a signal for maternal recognition of pregnancy by day 13 after AI. In essence, the cow must recognise that there is an embryo present or she will return to heat between 18 and 24 days. The strength of the signal is related to the 'size of the blanket surrounding the embryo'. This is determined by the quality of the uterine environment.

In conclusion, getting cows in calf depends on achieving a 90pc submission rate with a 60pc pregnancy rate to given services to result in a 90pc calving rate over a nine to 10 week period.

Dr Dan Ryan, is a breeding management consultant. www.cows365.com

Irish Independent