Northern Ireland’s College of Agriculture, Food and Rural Enterprises (CAFRE) has seen “performance ahead of expectation” for beef cross steers from its Holstein dairy herd.
These cattle are part of a project investigating the impact of reducing the age at slaughter from 24 months to under 22 months, while maximising the amount of grass and forage in the diet.
Slaughter data from Northern Ireland shows that, for 2018, 39% of all dairy cross steers failed to meet optimal carcass conformation and a further 42% failed to meet desirable carcass fat cover.
Of the 56,000 dairy cross steers slaughtered that year, less than 10,000 were under 22 months.
“These findings indicate that there is great potential for those involved in the dairy beef business to improve efficiencies,” said Natasha Ferguson, beef technologist with CAFRE.
In the project, 21 beef-sired calves were reared at the CAFRE Dairy Centre with all calves receiving the same level of colostrum management as replacement heifer calves in the unit.
Calves were reared using automatic calf feeders from one week of age, with each receiving high quality milk replacer at a rate of 750g of powder per day.
This was offered as a daily allocation of up to 6L for 49 days, after which milk volume was gradually reduced to day 56.
Calves were offered an 18% crude protein calf pellet and were weaned when they were consistently eating 1kg of pellets per day. Following weaning, calves were offered high quality grass silage and remained at a rate of 1kg concentrate.
“A key element to a profitable dairy calf to beef system is the efficient utilisation of grazed grass. Grazed grass is the cheapest source of energy for ruminants and is capable of supporting high levels of animal performance,” Ferguson said.
The calves were rotationally grazed during their first season at grass, entering paddocks with grass covers of 3,000kg DM/ha and exiting at 1,600kg DM/ha.
Calves continued to receive a daily allocation of 1kg concentrate at grass and performance was monitored regularly in conjunction with routine procedures. This concentrate level was increased if grass availability became an issue or if there was continuous rain for a period of time.
This batch of steers was housed early in October due to wet weather and poor ground conditions. They were then offered high quality grass silage with a D-value (reflecting digestibility) of 70 and 1kg concentrate.
Concentrate was withdrawn 6 weeks pre-turnout in order to achieve a ‘compensatory growth response’ at grass. The steers were turned out early in April to a set stock paddock system. Due to dry conditions during the summer period and low levels of grass growth, steers were offered 1kg of home-grown barley mix.
Silage was offered for a period from mid-June. All steers were gradually moved up to 5kg of the barely mix from July 5 until slaughter. The group average slaughter date was September 3, 2021.
Overall, 29% failed to meet conformation specs (compared to 39% of all dairy cross steers slaughtered in 2018) and 33% failed to meet carcass cover specs (compared to 42% of all dairy cross steers slaughtered in 2018).
CAFRE considers this to be ahead of expectation, with some animals slaughtered at 19 months.
In addition to this project, a batch of 19 Holstein steers were sourced from the CAFRE Dairy Centre to investigate the suitability of finishing these animals at under 22 months from a grass and grass silage based system.
It was found that the Holstein steers were “unsuitable for this system and require a later slaughter date”.