Farm Ireland

Friday 19 January 2018

Herd fertility is critical to profits

Liam Fitzgerald
Liam Fitzgerald

Liam Fitzgerald

After two weeks of fine weather, the feed and grass problems are, at last, declining and we can turn our attention to other matters.

The sole output from a beef cow is her calf, whether sold as a weanling, store or as a finished animal. Therefore, herd fertility is a critical factor influencing profitability.

Data from ICBF shows that for the beef herds on their database which are most likely to be above average in performance, the top 15pc have a calving interval of 364 days, which is excellent, whereas on the bottom 15pc it is 434 days (ie, 434 days between successive calvings). This difference of 70 days represents a loss of one calf per cow in the herd every five years. If the average value of a weanling (males and females) is €550, this represents a difference in profit of €110/cow between the top 15pc and bottom 15pc of herds.

The national average calving interval is 399 days. Comparing the top 15pc of herds with the national average in the same way shows a difference in profitability of €53/cow in favour of the top 15pc. No doubt there is great scope for improvement, but fertility is a complex issue and depends on getting several factors right.


Following the severe winter and spring, many might say that maintaining herd fertility would be an achievement in itself rather than going for a big improvement. However, data indicates that a major improvement is necessary on many suckler farms. The top performing herds are achieving the following targets:

  • An average calving interval of about 365 days.
  • 0.95 calves born/cow to the bull.
  • 60pc of cows calved in the first month of the calving season.
  • All cows calved within 12 weeks.
  • Calf mortality of 2pc at birth and 3pc up to 28 days.

Achieving these targets depends on a high level of herd management and herd health.

Assuming there are no herd health problems, the two main factors that influence fertility are cow body condition score and bull fertility for herds with a stock bull. Accurate heat detection is an added factor where AI is used.

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Condition score at calving should be more than 2.0 for individual cows, so aim for a herd average of 2.5 for spring calvers. Early calving cows will lose condition after calving while indoors, but should regain condition quickly on going to grass. They should be above 2.0 at mating and gaining weight.

Excessive weight loss post-calving will delay the return to heat. First calvers lose more weight after calving than mature cows and are also slower to gain weight at grass. They should get 1-2kg meal/day until there is adequate grass.

They may also suffer from stomach worms if they had not been dosed at housing, so a worm dose now could be beneficial. Health issues that affect conception rates are diseases such as leptospirosis and BVD, uterine infections and mineral deficiencies. Vaccinations to control these diseases and injections to correct deficiencies should be done before the breeding season.

Just because you run a bull with the cows, don't think you are relieved of heat observations. It is estimated that 3-4pc of bulls are infertile and a further 15-20pc are partially or periodically infertile.

Every year there are queries about fertility testing of bulls where problems have emerged, mostly late in the season when the damage is done. After turning out the bull, record the dates of the first matings and check for repeats 18-23 days later. Do not assume full fertility in a bull because he was satisfactory last year. Needless to say, all hoof problems should be treated well in advance of the breeding season. Bulls that were sick and had a high temperature are likely to have impaired fertility six to eight weeks later.


The pedigree bull sales are still going on. Young bulls need special attention. Normally, before the sale they are on a very high concentrate diet. After purchase, they should be brought down to about 50pc of the previous concentrate allowance and later to 2-3kg meal/day.

Sometimes the animal's feet are very tender after purchase, which results from standing and moving on concrete on the day of sale combined with their high-concentrate diet.

Provide plenty of straw bedding for the first few days and then move outside to a small paddock with a few other cattle. It is sensible to let the young bull mate with three or four cows before letting him run with the herd, and confine a young bull to about 20 cows.

Irish Independent