There are a number of options open to suckler farmers when sourcing replacements. Whether it is breeding your own heifers, purchasing in-calf animals or buying cows with a calf at foot, the emphasis should always be on bringing in a replacement animal that is better than the cows that are already in the herd.

The heifer, or cow, is responsible for half of the calf’s genetics and 100% responsible for rearing it. Sourcing replacements with good levels of milk, conformation and fertility is becoming increasingly difficult.

The traditional supply of Freisian cows crossed to a beef animal is not as plentiful as it once was. Using continental breeds with strong terminal traits has also reduced milk and fertility levels in the past. But in more recent years, there appears to be a swing towards maternal beef breeding.

Using the €uro-Star index, proven maternal bulls are becoming more common through AI. Calving surveys have also identified infertile cows for culling and which cows are ideal to produce replacement heifers.

Breeding home replacements

Breeding replacements from within the suckler herd is not straightforward. As the heritability of milk is low, breeding with maternal genetics is a long-term project. Selecting a maternal bull for breeding this spring means the calves will be born in spring 2015. Potential heifer replacements will not calve until at least spring 2017. When breeding your own replacements, heifers have to calve down at 24 months. Rearing heifers from birth is expensive and calving at 24 months is the quickest way to add new maternal genetics to your herd. If the aim is to replace cow type with a more maternal animal, then calving at 24 months is essential. Further to this, the entire herd should be bred to maternal bulls and the herd should have a high culling rate over three to four years. While male calves may suffer in terms of quality, it is the fastest method of replacing a herd. Home-bred heifers should only be selected from the cows that calve in the first half of the calving period, as these are likely to be the most fertile cows. While milk has a low heritability, fertility is extremely heritable.

Selection

Selecting heifers born in the first half of the calving period means that they will be heavier at weaning and have a better chance of reaching the target breeding weight at 15 months of age. The same group of animals is more likely to calve early in a compact calving season, which gives greater opportunity to get the heifers back in calf again (see Figure 1).

An early-calving heifer will potentially have three to four cycles to conceive, whereas late-calving animals that have fertility issues only have one to two opportunities. Over time, these less fertile animals are inclined to be bred out of the herd.

One of the main limitations to breeding your own replacements is the herd size. In a small herd, farmers cannot justify having two stock bulls. Likewise in a small herd, getting sufficient numbers of suitable heifers every year is a problem. Often heifers that are not ideal heifers have to be kept due to a lack of numbers.

AI does provide options for small herd owners. AI in autumn- and winter-calving herds is easier to manage, but spring-calving herds that are bred at grass using AI present more challenges, especially where herd owners work off farm.

Purchasing heifers

Another option is to buy maternal heifers annually. Purchasing from a known source provides many of the advantages that breeding your own heifers can offer. For instance, you will most likely know the herd history and health status. More importantly, you will know how the heifers perform.

For small- and medium-sized herds, this arrangement can offer a simple approach to heifer replacements. It means that in some herds, they can then focus on using terminal sires on all mature cows to produce cattle for slaughter or the mart.

Calving at 24 months

The average age at which heifers calve in the Irish suckler herd for the first time is approximately 32 months. The age at which heifers calve down for the first time is closely linked with the level of herd management. Successfully calving heifers at 24 months and getting them back in calf requires a high standard of stock management.

Most producers can get the heifer to calve at 24 months, with ICBF data showing that 85% of heifers that calve between 23 and 26 months calve for a second time. This is where herd management comes into play by ensuring the heifer is correctly managed to meet weight targets and is correctly fed to meet nutritional demand.

Fertility is closely linked to the weight of the heifer rather than the age of the animal. At 50% of mature cow weight, there is a 50% chance of the heifer cycling. At 60% of mature cow weight, there is a 90% chance of the heifer cycling.

As a rule of thumb, a heifer should be bred at a minimum liveweight that is approximately 60% of the mature cow weight. For a 650kg cow, the heifer should weigh at least 390kg at 15 months. Considering that the calf would have had a birth weight of 40kg to 45kg, there is no reason why a beef-bred suckler heifer cannot gain 350kg of liveweight over 15 months.

Over the 450 days, the heifer has a target weight gain of 0.75kg/day, yet many producers fail to achieve this. Heifers can cycle at a lighter liveweight. The reason the weight target is important is so the heifer is better developed and able to cope with the physical demand of rearing a calf.

The first winter period is when most heifers fall behind target. A February-born heifer being housed on 1 November at 300kg and being turned out to grass at 350kg in April will struggle to hit the target. Maiden heifers have to be managed separately in their first winter to ensure they gain at least 0.7kg/day indoors.

Management

The higher management level is often used as a reason for calving at the older age of 36 months, when heifers are viewed as being fully developed and therefore viewed as less problematic. However, even with calving at an older age, if the animal has not been correctly managed, she will be exposed to the same problems as heifers that calve at a younger age.

The target weight to calve a 24-month heifer is 90% of mature cow weight, which is approximately 585kg. Taking a heifer served at 400kg, it then has a target daily gain of 0.66kg/day over a nine-month period to reach the calving weight.

As mentioned earlier, calving at 36 months is expensive, as outlined in Table 1. From the figures outlined, there is an additional €300 cost saving (approximately)in rearing costs with a heifer calving at 24 months.

Add in the fact that the 24-month heifer will have produced a calf potentially worth €750 at weaning while the 36-month-old heifer has still not produced anything. It clearly shows how the age at calving influences profitability on suckler herds.

Farmers supplying the market

There is a market for supplying quality heifers as breeding replacements. Three discussion groups in Co Monaghan, facilitated by Teagasc adviser Mairead Kirk, have come together to market 40 maternally bred heifers in a special sale to be held on Thursday 1 May. The sale will be held in Ballybay mart at 5:30pm.

This is the second year the groups have held the sale. Members have realised the potential value in marketing these animals in a special sale. All animals being presented have been scanned and certified as being suitable for breeding, with mainly three-star to five-star maternal heifers for sale.

ICBF analysis has shown that five-star maternal animals have a shorter gestation and calving interval between their first and second calving. More importantly, calf weaning weight was on average 30kg heavier than one-star animals, which at €2.50/kg in the autumn is worth an extra €75 per calf. five-star heifers had greater longevity, with an additional 22% of five-star animals remaining on sampled herds compared to one-star maternal heifers.

Group members

Group member John Mulholland has a spring-calving herd of 42 cows with a 365-day calving interval. All heifers are calved at 24 months every year, compared the national average of 16%. All cows calved inside eight weeks in 2014.

Heifers are bred to Salers, which provide calving ease and milk in females. Heifers are now managed as a separate group until they are turned out to grass as calved heifers. Calving at 24 months has not stunted heifers, with all heifers calved in the past three years still in the herd as second- and third-calving animals. These animals have mature liveweight well in excess of 600kg.

A group of 17 yearling heifers on the farm has gained 0.97kg liveweight per day since birth and averaged 403kg on 5 March. Five heifers selected for the sale averaged 414kg on the same date at 13 months of age.

Peter Fitzsimons runs 70 Simmental cows and is firmly focused on producing spring-calving maternal cows that milk off grass. The herd has a calving interval of 373 days and again getting heifers to the required breeding weight has not been a problem. Heifers are due to be weighed in the coming week when scanned, but are over 400kg at 13 months of age.

Sean Greenan has taken a different approach to breeding as he farms on more marginal ground. He is using Stabiliser genetics to reduce cow size and improve maternal traits. The Stabiliser was bred in America as a composite animal.

It is made up of Angus, Herefod, Simmental and Gelbvieh breeding and is renowned for its fertility, milk and docility.

Sean’s herd has a calving interval of 371 days and improving annually. A group of 10 Stabiliser yearling heifers has averaged 1.13kg liveweight gain per day since birth, with an average liveweight of 371kg at 12 months on 5 March. Six heifers offered for sale are all four-star maternal animals.

The sale is BTAP approved and will also feature a presentation on the Gene Ireland breeding programme and two live demonstrations on bull and heifer selection.