Once Bred Heifers may be a good option for you

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3 December 2021

By Aimee Johnston

Bob Thomson extols the benefits of once-bred-heifers and reasons why it could be a good fit for farmers especially those who don’t like running bulls, as they are more predictable, less risky, and highly profitable.

Advice on the best way to increase beef profitability often leads to recommendations to farm bulls but many farmers reject that idea. Some farmers hate bulls with a passion.

If you are sick of hearing about farming bulls; but love prime-beef finishing, like beef breeding and making money then the once-bred heifers may be a good option for you.

Back in the 1990’s Massey University researchers carried out some great work on once-bred heifers. In essence, this is a process of weaning a calf from a two-year-old heifer in the process of finishing for prime beef. That research clearly showed that while a pregnant heifer would be lighter at slaughter, beef quality would not be compromised, and profitability would be much higher.

Following the promotion of the Massey work many farmers tried once-bred heifers, but most rejected the opportunity usually because of calving difficulty issues leading to calf loss and sometimes loss of the heifer too. Many commented that it was another management complexity that they could do without. On that basis it would be easy to dismiss the opportunity however it should be noted that a select few mastered their once-bred heifers management and have done well.

With the benefit of hindsight we can look back over the past 25 years and examine the reasons for the poor uptake of the once-bred heifers policy and explore how we might overcome the challenges and take advantage of the opportunity to make more money.

3 Factors that lead to better results

There are three big things that can help us get much better results from once-bred heifers than we got back in the 1990’s and these are linked.

The first is with the results from the Beef + Lamb New Zealand genetics dairy-beef progeny test where over the past seven years more than 120 beef bulls have been assessed for a wide range of traits including calving ease, growth, and beef quality.

The second big thing is that results from fixed-time-artificial insemination (AI) are much more reliable and predictable meaning we can use the best beef bulls via AI and reap the benefits of easy calving, great post-birth growth and better beef quality. With fixed-time-AI, heifers are synchronised to cycle and be mated on one day. On average over 50% of heifers will be pregnant to a one-shot AI programme. Following the one-shot AI you can be content, or repeat the AI process, or follow-up with naturally mated bulls.

The third big thing is beef systemisation which is usually applied to bull farming. This is out of the necessity to farm in smaller mobs with more discipline around rotation length and shift frequency. This enables higher average pasture cover and therefore higher pasture growth rate. That same discipline from bull beef systemisation can be applied to heifer management which in turn helps with better feeding during gestation, lactation and through to finishing.

At the time of writing, the latest report from the Dairy-Beef Progeny Test was unpublished. I have included selected results from the April 2020 report below. For the latest results, check the B+LNZ Genetics website.* Each year, a new batch of bulls are added to the list. Please note that as new bulls are added rankings will change as new information on their progeny emerges.

Table 1 shows the top 15 bulls for the criteria outlined. These bulls offer the opportunity for use in dairy herds to generate good finishing stock for beef finishers while at the same time affording the dairy farmer a great value proposition. These same bulls provide good value for once-bred heifers through a fixed-time-AI programme. That is, dairy-beef heifers can be generated from dairy herds which in turn can be mated to beef bulls for once-bred heifers production.

A case study of Pamu’s Rangitaiki Station once bred heifers programme

A good example of a commercial farming company taking advantage of the once-bred heifers programme is Pamu (Landcorp’s brand name) with its Rangitaiki Station Rangitaiki which is about 50 kilometres west of Taupo. The 8700ha sheep, beef and deer farm had established a profitable 2500ha bull finishing unit five years ago. They wanted to look at how farm profitability could be further increased without having to farm more bulls. The bull finishing unit provided a good template, from a beef systemisation perspective, from which they could establish a once-bred heifers programme. In essence, the cell grazing set-up from the bull unit was upsized for the heifers. For example when 50-R1 bulls or 25 R2 bulls are managed in a 10ha system this was increased to 40ha for the once-bred heifers unit and stocked with 200 R1 heifers or 100 R2 heifers. At the start of winter the bull unit stocking rate was 900kg liveweight/ha. The once-bred heifers unit has been reduced to 800kg LW/ha on a ‘like for like’ basis because heifers are less efficient than bulls and required to gain more bodyweight across winter than bulls.

Table 2 Stocking Rates for once bred heifers

Rangitaiki is a tough environment demanding a 160-day winter rotation extending from May until September. Winters are as cold and harsh as the South Island but nevertheless a low-cost all pasture system is applied for the bull and once-bred heifers units. High autumn pasture covers are required with a target of 2700kg DM by May 1. By then pasture growth rates plummet to average 9.25kg DM/ha for the next four months and up until September. While the high autumn covers are essential, a bit like ‘hay in the barn’, the winter feed demand must be ‘bent’ downward resulting in low winter liveweight gain. We know from another good piece of research from Massey University that first calving two-year-old heifers need to gain bodyweight during pregnancy to help with calving ease and so with two day shifts and the discipline of the systems this can be planned and implemented.

The key to systemisation at Rangitaiki is to implement grazing management with good structure and process whereby cattle have an allocated area with sufficient cells to enable two daily shifts and a 160-day winter rotation. The rotation length coupled with stocking rate has been modelled to deliver high average pasture cover. In practice we have found that a good system delivers at least 20% more pasture simply by exploiting the ‘solar panel’ effect whereby every leaf of pasture is another source of energy. While Rangitaiki requires 160-day winter rotations, by comparison, a winter-friendly Northland needs just 60-days to achieve the same effect.

Pasture covers are well in excess of the optimum across some months and especially in the autumn. This comes about for two main reasons. The first reason is that with an all-pasture system ‘monster’ covers are required to get through winter. The second reason is that pasture is deferred on between 15-20% of the area in late spring meaning that pasture quality and optimum pasture cover is maintained across 80-85% of the system area. The deferred pasture has proven to be valuable as a means of slowing down rotation lengths in early autumn and therefore building average cover to at least 2700kg DM/ha by May 1.

Replacements, a simple and low-cost way

A lot of planning and detail has been implemented on Rangitaiki. There’s another four to five months to go until calving in September followed by early weaning in mid-January. Heifers will be drafted to kill immediately following weaning with at least half sold then and the rest by the end of March 2022 when the first cycle of once-bred heifers will be completed.

Results to date are as follows:

891 yearling heifers mated in total:

639 dairy-beef heifers (bought-in)
252 beef heifers (home-bred).

53% of once-bred heifers heifers scanned in-calf to a one-shot fixed time AI.

85% or 761 heifers in-calf following one-shot AI followed by one and a half cycles of natural bull mating:

91% of dairy-beef heifers in-calf (earlier born and first-cross)
71% of beef heifers in-calf (mated one month earlier than normal for once-bred heifers).

Another important twist with the Rangitaiki once-bred heifers programme is that the most efficient calf producing dairy-beef heifers will be retained as replacements for the beef herd. To achieve that outcome, the heifers in-calf to fixed-time-AI have been identified thus reducing the need to record birth date.

A total of 200 replacements are required and so the heaviest 250 calves will be rematched with their mothers post-weaning. Once rematched, those heifers without calves will be drafted-off for finishing. The 250 heifers with calves will again be weaned and the heaviest 50 drafted-off these for finishing leaving the best and most efficient heifers as replacements. This is a simple and low-cost way of selecting the best replacements.

The bottom line of once-bred heifers

The bottom line is that a once-bred heifers programme is not for ‘cowboys’ or those looking for less work; on the contrary a once-bred heifer programme requires some management discipline and attention to detail but the rewards are worthwhile - see Table 3.

Table 3 has been modelled and generated from Farmax. Each policy has 100 hectares with the same potential pasture growth rate of 8500kg DM per annum. In terms of gross margin bulls are just 10% ahead of OBH but are 45% more profitable than finishing heifers. OBH Feed Conversion Efficiency (kg DM/kg Product) is similar to bulls and something which we will need to pay attention to in relation to our carbon footprint.

Table 3 How the gross margins compare 1000px

In summary the once-bred heifers policy can be dusted-off and rejuvenated on the basis that with new information and the benefit of experience results will be more predictable, less risky, and highly profitable. The key to success is attention to detail and adoption of the latest information from the likes of the dairy-beef progeny test programme, talking with your vet to get the latest techniques on fixed-time-AI and the adoption of beef systemisation.

*https://www.blnzgenetics.com/progeny-tests/beef-progeny-tests

• Bob Thomson is an Agribusiness consultant, specialising in sheep and beef.

Aimee Johnston

Marketing & Cattle Farmer

Aimee Johnston is a beef cattle farmer based in Otago, New Zealand, as well as part of the Marketing team here at Te Pari Products. Working closely with farmers and livestock producers, she combines practical on-farm experience with her role in agricultural marketing. Aimee regularly writes articles for the Te Pari website, covering livestock handling, farm management, animal health, and industry developments. Her writing focuses on providing practical, real-world insights that help farmers improve efficiency, animal welfare, and productivity.

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