At the recent Teagasc Suckler Breeding Event in Kildalton one of the issues highlighted was the value of calving down replacement heifers at 22 -26 months of age. Many of the myths associated with calving heifers at 2 years old were dispelled by the excellent 60 cow college herd which was on show and all of the cows were calved down for the first time at 22-26 months old.
Why do it?
There is more output from the heifer over her lifetime (more calves produced); stocking rate is reduced compared with calving heifers at older ages and there is potential to reduce the number of stock groups. It also reduces the cost. Grange work shows that for a 50 cow herd with a 20% replacement rate each additional month that calving is delayed costs €500 or €50/heifer/month. Therefore calving down heifers at 2 years versus 3 years in a 50 cow herd will leave €6,000 more profit per year.
Why are farmers reluctant to try it? Only 16% of heifers calve at 22-26mths
They believe that: Heifers aren’t big enough at 15 months for bulling; It will stunt the heifers growth; They are too difficult to calve; They won’t go back in calve again to calve as 2nd calvers; They are not that saleable if things go wrong at calving.
Dispelling some of the Myths (ICBF Figures)
We often put up many reasons as to why not to calve heifers at 24 months, such as if they calve at 2 years they will not calve again at 3 years. The table above doesn’t really support this notion. Heifers that calved at 23-26 months had as good a calving interval and calved down again as a second calver as heifers calving down in the older age categories. Another reason is that they are harder to calf at a younger age. The figures do show that younger heifers do have only slightly higher calf mortality. On the same token heifers, irrespective of age, will be more difficult to calve and as the figures show will need a high level of assistance at calving. This could be reduced if there was more selectivity in the sires put on heifers. Even the younger calving heifers are being mated with sires with an average calving difficulty of 4.7%. Interestingly dairy farmers try and mate their heifers calving down at two years with sires with a calving difficulty of 2% or less. Beef sires for heifers may never drop that low but aim for 4% calving difficulty or less on heifers.
Heifers that are to calf down at two years of age will;
Come from the best cows in the herd and be sired by bulls with strong maternal traits.
Be born early in the calving season to allow them to be heavier at bulling
Need to achieve a daily live weight gain of 1.1-1.3kg/day up to weaning.
Have to be fed to achieve 60-80kg liveweight over the first winter so they will need good quality silage plus 1-2kg of concentrates.
Be turned out early in spring to grass to achieve good weight gain in the run up to calving
Have reached 60% of their mature weight by bulling.
Be bred to a known easy calving sire (Ideally less than 4% calving difficulty)
Have achieved 80% of their mature weight at calving.
Need preferential treatment if remaining indoors for a month or more after calving down. (Good silage plus 2-3kg concentrates)
Choosing AI bulls
ICBF have developed a spec for an active bull list. This is an online application available from the ICBF homepage. The user can sort and filter on any of the columns. They can do this with multiple columns if they wish.
There are two active bull lists, one for replacement and one for terminal. The replacement index should be used for producing replacement heifers and should be used by farmers breeding their own replacements or breeding heifers for sale. The terminal index should be used where animals are intended for beef (farms where replacements are bought in or where enough AI has already been used to produce the replacement heifers needed). continued page 35
What to look for in the Replacement Index
Focus on Cow traits, after all this is what you are trying to improve!
1. Daughter Calving Interval. This is probably the single biggest area pulling down profitability on Irish farms. The National Average for Calving Interval is 395 days. Aim for a calving interval of 0 or below
2. Daughter milk. This is another big area for improvement in Irish suckler farms. Target a minimum increase of 5kg.(+5kg)
3. Daughter Calving Difficulty. This is a measure of the ability of the heifer to calve when she is introduced into the herd as a replacement. Calving difficulties can arise from both the dam and the sire side. This is a measure of the dam’s side. The aim should be that this figure be no greater than average calving difficulty (5.28%)
4. Progeny Calving Difficulty. This should be as low as possible. This is a measure of the direct calving difficulty from the sire. Keep below 4% for use on heifers and keep below 8% for mature cows.
5. Overall Replacement Index – When you are satisfied with a number of bulls for calving interval, milk and calving difficulty, choose within this list the bulls that have the highest overall replacement index. This means you will be breeding a heifer suitable as a replacement with the best possible value for beef traits as well.
Please note that you should keep RELIABILITY of figures in the forefront of your mind. All bulls on Active bull list have a reliability of 50% or higher. However, a reliability of 75% or more is desirable for AI.
Teagasc Kildalton College Horticultural Careers Day
Kildalton College will host a horticultural careers day on Thursday 8th May starting at 10.00 am. Information on courses, applications, grants, accommodation will be available as well as guided tours of the facilities. Kildalton offers FETAC level 5 and level 6 horticulture courses and in conjunction with WIT also offers a three year Ordinary Degree in Horticulture. All are welcome.
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