Heavier and more in-spec carcasses - early life nutrition’s role in dairy-beef

Early life nutrition represents a potential period of opportunity for dairy-beef producers, Head of Animal and Bioscience Department at Teagasc, Professor David Kenny told a recent gathering of scientists, beef industry representatives and farmers.

Addressing the International Dairy Calf to Beef Conference, an event organised by Teagasc in partnership with ABP and BSAS, and centring his presentation on the topic of the ‘Effect of early life nutrition on the performance of dairy origin cattle’, Professor Kenny summarised research studies pertinent to this topic.

The starting point in effective dairy-beef nutrition strategies, he noted, is ensuring calves are provided with adequate volumes of colostrum to ensure the development of passive immunity – something often lacking in calf rearing systems across Europe.

After this, milk feeding programmes must be sufficient to support the calf’s maintenance, temperature regulation and immune system requirements, while providing a surplus for the growth of muscle and fat.

Striking the balance between the calf’s consumption of milk replacer and concentrate feeds is also of the utmost importance, he noted, with this being critical to ensure rumen development – a necessary step required before animals can be transitioned to a forage based diet – and making calf rearing economically viable during a period when animals have the highest feed efficiency potential.

Effects on animal performance

Although prefacing with the fact that very few studies have been completed on the overall impact on animal performance to finish from early-life nutrition strategies, Professor Kenny did share studies undertaken in Ireland by both Teagasc and University College Dublin, summarising these by saying: “The majority of the variation witnessed in carcass performance occurred due to the feeding strategies being implemented over the first 12-15 weeks of life”.

Of note in this regard was a study recently completed by Jennifer Abbot, a Teagasc Walsh Scholar based in Teagasc Grange, who examined the impact of pre- and post-weaning feeding strategies to 15 weeks of age on Angus and Holstein Friesian males carried to beef as bulls under a 16-month bull system.

Under this study, calves were assigned to one of two pre-weaning planes of nutrition: moderate (M PRE) or high (H PRE). During the pre-weaning period, calves had ad-lib access to concentrates.

Calves on the M PRE treatment were offered: Stage I (7 days of age to arrival at Teagasc Grange Research Centre, d 0) 6L/day containing 750g of milk replacer , Stage II (d 0 – 36) the same as stage I, Stage III: (d 36- 50) 6L/day incrementally reduced to zero.

Calves on H PRE treatment were offered: Stage I: (7 days of age to arrival at Teagasc Grange Research Centre, d 0) 8L/day containing 1,200g of milk replacer, stage II: (d 0 – 24) 10L/day containing 1,500g of milk replacer, stage III: (d 24 – 29 ) 10L/day gradually reduced to 6L, stage IV: (d 29 – 36) 6L/day, stage V: (36 – 50 d) 6L/day incrementally reduced to zero.

Post-weaning, calves were assigned to one of two, four week long post-weaning diets, moderate (M POST) or high (H POST), where they received a daily concentrate allowance of either 1.5kg or ad lib access, respectively.

Irrespective of feeding system, all calves were treated the same following the post-weaning period and were managed in accordance with the standard Teagasc 16 month old dairy bull beef system blueprint.

Some of the key findings from this research were:

• Calves on H PRE diet had greater liveweight at weaning compared to M PRE.
• Calves on H POST had greater liveweight at the end of the post-weaning period, compared to M POST.
• At slaughter, both liveweight and carcass weight were greater for animals offered H compared with M post-weaning, irrespective of their pre-weaning diet.
• There was no effect of pre-weaning plane of nutrition on either liveweight or carcass at slaughter.
• There was a tendency for pre but not post-weaning diet to affect both carcass conformation and fat scores, M PRE having a slightly higher conformation and fat score than H PRE, but no significant difference observed.

Table 1: Effect of pre and post-weaning plane of nutrition (M or H) on performance of dairy-bull calves slaughtered at 16 months of age

*Non-significant (P>0.05) pre-weaning x post-weaning diet interaction was observed

Table 1 above tracks the performance, across all feeding strategies, from the calf rearing period right through to finish. Of note was the differences in carcass weight and conformation observed. Commenting on this, Professor Kenny said: “It was really in that four week post weaning phase when the animals were offered a high plane of nutrition that the differential in carcass weight really created itself. While there was a moderate enough difference post weaning, that essentially grew after the post-weaning period for the calves on the high rate of nutrition post weaning and noticeable differences in liveweight were witnessed at the end of the first grazing season, right through to housing before finish and then in the liveweight at slaughter. That four week period of a high plane of nutrition post weaning yielded a carcass advantage of 30kg,” Professor Kenny said.

For further details on the above, access Professor Kenny’s full paper from the International Dairy Calf to Beef Conference here.

Diary date – Teagasc National Beef Conference

The Teagasc National Beef Conference 2024 takes place on Tuesday, 19 November at 5pm in the Landmark Hotel, Carrick-on-Shannon, Co. Leitrim, N41 N9W4.

The theme of the conference is 'Sustainable Beef Farming: Pathways to a greener future'

See the National Beef Conference Programme here.