Tanygraig Project Final Update - February 2025
Key results
- After turnout the daily liveweight gains of both sets of animals remained fairly similar throughout the grazing period at 0.77kg/day (concentrates) and 0.81kg/day for the silage only group.
- The concentrate group consumed 159.75kg of concentrate more than the silage only group and this amounted to a total cost of £71.89. Assuming a sale weight of £2.90/kg liveweight for the extra 27.28kg produced by the concentrate group this would account for a positive margin of £7.23 for the concentrate group over feed costs.
- In order for the compensatory growth system to succeed, a target gain of 0.6kg/day should be achieved throughout the winter. At Tanygraig, the concentrate group averaged 0.58kg/day throughout the winter compared to the silage-only group averaging 0.4kg/day.
Background
Over the winter of 2023/24 twenty-one suckler bred store cattle were kept on separate diets of either red clover silage and concentrates or red clover silage only. The aim of the project was to explore reducing the concentrate levels fed to store cattle during the winter and whether the cattle would compensate for this lack of nutrition once out at grass in the spring, while not taking a knock in growth upon turnout.
Purpose of the work
The project aims to trial eliminating concentrate feeding the weanlings during the first winter to quantify the benefit of reduced feed costs without impacting on overall performance by reducing costly winter feeding and making better use of grass which is ultimately the cheapest feed source.
What we did
The Aberdeen Angus store cattle produced on the farm were split into two groups of 11 and 10. After weaning on 16 November the group of 10 received only silage for the remainder of the season. A summary of the analysis of the silage can be seen below in table 1.
Table 1. Analysis of Silage 2023 season.
The remaining 11 cattle received adlib silage and 3kg of concentrates for one month after weaning and then received 1.5kg a day until turnout on 2 April. The cattle were weighed 5 times throughout the project. The analysis of the concentrate feed fed to the cattle can be seen below in figure 1.
Figure 1. Concentrate feed analysis.
A Beef Monitor was used (from Ritchie) together with conventional weights through a crush to assess the cattle performance and trial the Beef Monitor. The Beef Monitor worked well within the housing period but was not found to be as accurate when the cattle were at grass and stock were being moved from field to field. Due to a wetter summer the cattle did not drink as much as expected and the number of trips via the scales to water was much reduced. Working at a group level to get accurate results for the trial also proved difficult, as cattle were not necessarily all weighed the same day. Therefore, by bringing in the cattle and weighing them via a crush, we were able to assess the whole group on a single day, and then plot this data against other weighing’s but this was labour intensive. The cattle walked in happily to the beef monitor which compared to weighing through the crush was a lot less stress on the cattle and also improved health and safety for the farmer as it involved less handling of animals.
Outcomes
The concentrate group started at an average weight of 280kg while the silage group starting weight was 290kg. Over the period the concentrate group put on a total weight of 177kg while the silage only diet put on a total weight of 150kg. This weight gain is shown in Figure 2 and Table 2 below.
Figure 2 – Cattle average weight gains (kg) on both silage only and concentrates and silage diets
Table 2 - Raw data of cattle average weight gains (kg) on silage only and concentrates and silage diet
The daily liveweight gain of the animals of both groups remained fairly similar between weaning and the February weighing. After this point the concentrate group increased its daily gain to 0.91kg/day compared to 0.28kg/day for the silage only group. Then after turnout the daily gains of both sets of animals remained fairly similar throughout the grazing period at 0.77kg/day (concentrates) and 0.81kg/day for the silage only group. Figure 3 and Table 3 shows the breakdown for the groups daily liveweight gain (DLWG).
Figure 3 – Average DLWG of cattle on different diets.
Table 3 – Raw data of average DLWG (kg/day) of cattle on different diets
Over the winter period the concentrate group consumed 159.75kg of concentrate more than the silage only group and this amounted to a total cost of £71.89. Assuming a sale weight of £2.90/kg liveweight for the extra 27.28kg produced by the concentrate group this would account for a positive margin of £7.23 for the concentrate group over feed costs.
During the project the cattle on the silage only diet had particularly poor daily growth during the February to April period and this was coupled with very little extra growth in terms of compensatory growth during the spring at grass. Therefore, in order for the compensatory growth system to succeed, a target gain of 0.6kg/day should be achieved throughout the winter, using quality silage or concentrate supplementation if cannot be achieved with forage available. Table 4 below from Teagasc gives recommendations required on the D-Value of the silage. At 66 D-Value the suggestion is to feed just up to 1.2kg/day. Then after turnout it would be expected that the animals compensate and increase their growth rates during the grazing season as well.
Table 4 – Teagasc guideline daily feeding rates based on silage quality
