Selecting AI bulls for suckler herds
Levels of AI usage in suckler herds is low nationally with an estimated 20% of cows bred to AI sires year on year. Usage amongst maiden heifers is higher often due to the presence of one stock bull on small suckler herds. Alan Dillon, Teagasc Beef Specialist has advice on selecting AI bulls
Purpose - Replacement or Terminal?
When choosing an AI sire, the first thought that should cross a farmer's mind is what purpose will the progeny be used for potentially? If any females are potentially to be bred as replacement heifers in the suckler herd then maternal sires with high sub-indices for milk and docility should be used. A number of bulls, particularly those with more terminal characteristics have a negative figure for milk. These are not suitable for breeding replacement heifers. Aim for a figure in excess of +5kg for milk to ensure the progeny will have adequate milk to rear a calf. While carcass characteristics are the most important traits for terminal bulls, they are also of importance for bulls to breed replacement heifers. Remember the cow is 50% of the calf’s genetics. It’s not uncommon for some traditional breeds with very easy calving characteristics to have negative carcass weight figures, again this needs to be checked and unsuitable bulls avoided. Target a bull with a minimum carcass figure of +10kg for breeding replacement heifers to ensure their progeny have the genetics to grow and perform.
Remember the cow is 50% of the calf’s genetics
Excessive carcass conformation is best avoided when breeding replacements. Excessive muscle in the hind quarters can lead to more difficult calvings which may influence fertility on subsequent breeding seasons.
Docility is crucial
Docility needs to be one of the main selection criteria for suckler herds not only from a health and safety point of view but also from an efficiency target. Time is scarce on farms now and stock that are hard to handle, being wild and aggressive have no place on farm.
When selecting bulls for terminal figures, the main focus is on calving difficulty, carcass weight and carcass conformation. There are a number of bulls available with high carcass weight and relatively low calving difficulty figures. These are the bulls that should be focused on rather than those with very high levels of expected calving difficulty, which will lead to higher vet costs and possibly have a negative effect on future fertility.
Table 1. Example bulls for terminal and replacement characteristics
Advantages of AI
- Potential to access top genetics across all breeds (Replacement & Terminal)
- More cost effective for smaller herds
- Higher reliability if team of sires selected
- Reduces the safety risk of having a stock bull
Heat detection aids
- Simple detection aids such as scratch cards/pads/tail paint
- Electronic heat detectors that use a teaser bull to transmit a signal from a neck collar to a tag in cows ear by text message.
- Synchronisation programmes to trigger onset of heat and use fixed time AI
- Restricted suckling from 30 days post calving
On this week's Beef Edge podcast Martin Shaughnessy from Co. Mayo joins Catherine Egan for a Beef Edge Masterclass to discuss his beef system & how he uses AI on his farm. Catch it here below.
For more episodes and information covered on the Beef Edge, visit the show page at: www.teagasc.ie/thebeefedge