Farm Ireland

Sunday 17 December 2017

Focus on basics to halt calving woes

Mary Kinston

With the start of mating getting ever closer, we should assess the success of last year's mating. As most farmers are around 6-10 weeks into calving, the percentage calved has been a common question at discussion groups.

Many would aim for 75-85pc calved at six weeks for a spring-calving herd and may often achieve this figure year after year, while others would fall short of this. However, it has become evident from many group discussions that there are more farmers dissatisfied with this year's calving rate and, as a result, last year's mating, when compared to their herd's performance in previous years.

When faced with a poor calving rate, it is human nature that we will try to find some fact in last year's mating that we can assign some blame for this failure. Common ones listed by farmers this spring have been minerals, especially phosphorous as cows were noted to be chewing stones, poor body condition score and animal health problems. The possible causes listed are stomach fluke, liver fluke or diseases such as IBR or BVD, inadequate bull power, or even shortage of pasture and tight grazing. Certainly, nutrition, genetics, body condition score, minerals, animal health, heat detection skills, reproductive infections such as BVD and Lepto, AI storage and handling, bull fertility and numbers can all have a detrimental impact.

One theory is the possibility that too much starch in the form of ration was fed during last year's mating because of a slow, cold spring.

The thinking is that this promoted insulin production, with high insulin levels having a detrimental effect on embryo quality. However, the reality is that we are in the business of commercial dairy farming, with limited measurement of all these factors, so we can't assign true blame to any particular issue. So, while I'm not suggesting that you shouldn't assess your performance and identify areas for improvement, it's a complex biological system and that's why it's time to focus on the basics and get them right.

A successful mating this year and compact calving in 2012 really starts with last year's heifer calves. Their rearing will have determined the quality of this year's maiden heifers. To establish and maintain a compact calving spread, it is important that the maiden heifers are mated at the same time, or even 7-10 days before the dairy herd.

Late-calving heifers have a lower chance of conceiving at mating and will either become late-calving cows or will be empty.

Therefore, heifers need to achieve target weights and have weight gain continually assessed throughout the mating period. We are aiming for 60pc of mature body weight at the start of mating. It's also important to make sure that the bulls selected for the heifers, whether natural or AI, have a low calving difficulty. Where natural service is used, monitor bull serving behaviour throughout mating to ensure they are serving correctly.

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For the pre-mating period of the main dairy herd, implement the following:

  • Good planning is required to achieve compact calving and the process begins by selecting the dates when mating starts and stops.
  • Minimise condition score loss in early lactation and consider scoring the cows two weeks before mating. Aim for no more than 15pc of cows to have a condition score of -- or less than -- 2.75, and for the average condition score loss of the herd to be no more than 0.5 from calving to mating.
  • Make sure the cows have good nutrition and no undesired condition score losses are being incurred by monitoring for:
  • Suitable pre- and post-grazing yields.
  • Supplements offered are being consumed.
  • Daily milk production, milk fat and protein.
  • Cows chewing their cud and manure consistently.

Take action if any of these remain abnormal for several consecutive days or if several of these parameters are all abnormal at the same time.

  • Choose and buy your heat detection aids and make sure everyone knows how to use them.
  • Use tail paint to detect for non-cycling cows four weeks before mating, with the goal of having them all identified by one week before mating. If your pre-mating cycling rate is less than 65pc of your herd, then you have a cycling problem.
  • For treatment of non-cyclers, start by figuring out how long each non-cycler has been calved. If this is more than 30 days, assess what factors are causing this animal to become sub-fertile and treat accordingly. Problems could include deficiencies in heat detection, poor heifer rearing and under-weight heifers, high percentage of heifers which require an extra 10 days to start cycling, breed, body condition score, abnormal calving and uterine infections.
  • Bull power. Do you have enough bulls and are they in good health and condition for mating?

Mary Kinston is a farm consultant based in Kerry. Email:

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