10 Aug 2022

Beef breeding indices explained

At the recent Teagasc National Beef Conference in Kilkenny, Andrew Cromie of ICBF gave an overview and an evaluation of the Beef Breeding Indices which are available to help beef farmers to produce better quality and more efficient animals.

At the recent Teagasc National Beef Conference in Kilkenny, Andrew Cromie of ICBF gave an overview and an evaluation of the Beef Breeding Indices which are available to help beef farmers to produce better quality and more efficient animals.

Understanding Beef Breeding Indexes - The Suckler Beef Value (SBV) was first introduced in 2007 and indicates the expected profit (€) per progeny from a breeding animal (male or female). It is made up of various sub-indexes including weanling, carcass, daughter milk and daughter fertility. A quick summary of each index is given here.

Overview of Key Indexes

Index of Suckler Beef Value (SBV) - This is a measure of the overall beef value of an animal.

Index of Weanling Export - The ability to produce profitable weanlings.

Index of Beef Carcass - The ability to produce profitable carcasses.

Index of Daughter Fertility - The ability to produce daughters with good fertility.

Index of Daughter Milk - The ability to produce daughters with good milk production.

In the process of genetic evaluation, data is collected from Irish beef farms, marts and factories on each individual animal. Current evaluations are based on analysis of over 4 million records from these sources. Non-genetic effects such as age, sex, breed and herd management are then corrected for to give an indication of the animals genetic merit for key traits such as carcass weight, weaning weight, calving difficulty, cow milk, cow fertility. (Forty traits in total are evaluated on each animal). These traits are then summarized into the various profit indexes outlined above. Thus, an animal with an SBV of €150 is expected to leave an additional profit of €150 per progeny compared to a bull with an SBV of €0. Animals will have strengths and weaknesses in different areas and this is then reflected in their various sub-indexes.

€uro Star Value - In addition to the €-value figure for SBV and each sub-index, all animals are also ranked on the basis of stars (or €uro-Stars) into 5 categories, based on % rank within the breed, with 5 stars indicating top 20% for the trait, and 1 star indicating bottom 20% for the trait. The benefits of the star rating is that they quickly allow a farmer establish where an animal is strong or weak. For example, a breeding bull could be 5 stars for overall SBV (top 20%), but only 2 stars for a trait such as maternal milk. This shouldn’t surprise as the animal that has everything is often very hard to find!

Do €uro-Stars Work? One of the first questions asked by farmers and breeders is whether the new €uro-Star indexes work? For example, if he buys a bull based on €uro-Star indexes, how confident can he be that the bull will deliver progeny that leave more profit at the time of sale, than a bull with no information or only average values?

Recent work by ICBF has clearly demonstrated the value of €uro-Stars. For example, of the 6,191 steers slaughtered during the week ending 1st February 2011 (with carcass index values), 1,067 were 5 star steers and 1,282 were 1 star steers (the progeny of high and low index bulls).

A comparison of slaughter performance for these animals indicates that on average 5 star animals were:

74 kg heavier in terms of carcass weight (at the same approximate age), had better conformation (by 3 conformation points) and had an increased carcass value of over €300 compared to 1 star animals.

Similar trends are apparent for other categories of animals (e.g., heifers, young bulls and cull cows) and for animals traded through marts. The bottom line is 5 star animals deliver more profit at the time of sale than animals of average or low genetic index. The evidence is compelling. When buying a bull or selecting AI straws this spring, farmers should focus on the €uro-Star values, as these values will result in increased profit for their farm business.

Achieving a 365 day calving interval - Shane Mc Hugh Teagasc Better Beef Farm adviser gave a presentation on achieving a 365 day calving interval in suckler herds. The profitability of a suckler herd is directly related to the number of calves reared per cow or heifer served annually. Recent figures from ICBF show that the average calving interval for all suckler herds in the country is 406 days which is a long way off the target of 365 days. A cow that does not calve every 365 days is a drain on the system and not earning her keep. Only 0.78 of a calf per cow per year is produced on average. This means that in a 100 cow suckler herd the average farmer is weaning 78 calves from 100 cows which is grossly inefficient. The target is 95 live calves per 100 cows (0.95/calves/cow/year). If this farmer was producing weanlings and could raise this figure by 0.1, it would mean an extra 10 calves to sell or approximately €6000 - €7000 extra in sales for the year, which would be a big rise in output on any farm. It has been shown in the past that it costs between €500-€800 to keep a suckler cow for the year depending on a number of variables including land type and whether the cow calves in the spring or autumn. It is therefore essential that she produces a viable calf every 365 days to deliver an output which will cover this expenditure and produce a profit.

There are two main ways to improve suckler cow fertility:

1. Increase conception rates: If 100 cows were put to the bull and achieved 60% conception in each heat period, then the following pregnancy rate would be achieved. 3 weeks – 60 in calf; 6 weeks – 84 in calf; 9 weeks – 93 in calf and 12 weeks – 97 in calf

This means that a conception rate of 60% leaves just 3 cows empty after a 12 week breeding season (natural service or AI). If this conception rate was to drop to 40%, then after 12 weeks breeding there would be 14 ‘empty’ cows. Good heat detection, AI technique and timing, avoiding difficult calving and stock bull fertility are all important aspects in ensuring high conception rates.

2. Reduce the interval between calving and conception

Cows undergo a period of recovery after calving before normal fertility is regained. The uterus needs time to recover from the calving process and return to normal size. This takes up to 40 days or longer if there was calving difficulty or uterine infection. The length of time that ovaries take to regain normal cycling after calving can range between 25-180 days in beef cows and is related to body condition score and plane of nutrition. First calvers can often have a delayed return to oestrous due to poor condition score at calving and incorrect nutrition post calving. The target is to have most cows bulling by 50 days post calving.

Bull Fertility - Bull fertility is key to maintaining a compact calving period, maximising the genetic potential and value of the calf crop and overall herd profitability. Ensuring the herd sire is ready for work requires forward planning as semen production takes 60 days. The bull must be in good health and ready to work at least 10 weeks before the breeding season begins.

Key Points: Bulls must be able to maintain body condition score (ideally BCS 3), repeatedly mount and serve cows and place fertile semen in the cow for 12 weeks and have a long working life in the herd.

Good libido is important, especially in larger herds or in difficult terrain so that the bull is active in seeking out and successfully serving all cows in heat. Quarantine new bulls for four weeks after purchase for health screening and acclimatisation. Avoid sudden changes and do not overfeed as this can reduce fertility and lead to feet problems.

Check feet and legs well in advance of the breeding season, as good locomotion is essential for getting cows pregnant. Take remedial action if required. Provide exercise where possible (e.g. site feed and water at opposite ends of the shed or field). Approximately 25% of all working bulls are sub-fertile or infertile.

Watch the bull working to check he is serving cows correctly.

Rotate bulls or scan cows early so that an infertile bull or sub fertile bull can be identified early. Even bulls that have passed a breeding soundness examination can go lame or suffer reduced fertility during the breeding season.

Record when you see a cow being mated and watch for signs of cows coming on heat repeatedly.

Don’t overwork a young bull (20 cows maximum for first season)

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