01 May 2025
New insights on dairy-beef post weaning feeding strategies
A recent study completed by Jennifer Abbot at Teagasc Grange has shed new light on possible post-weaning feeding strategies to improve the carcass performance of dairy-beef males.
Results from this study, which examined different pre- and post-weaning feeding strategies for Angus and Holstein Friesian males carried to beef under a 16-month bull system, were discussed at the recent British Society of Animal Science (BSAS) Conference, which took place in Co. Galway.
“This study aimed to assess the impact of both pre- and post-weaning nutrition and their interaction, on performance and carcass composition in dairy-bred male calves slaughtered at 16 months of age,” Jennifer Abbot, a Walsh Scholar based in Teagasc Grange, explained.
Feeding regimes
Over the duration of the study, Angus or Holstein Friesian male calves were assigned to either a moderate (M Pre) or high (H Pre) pre-weaning plane of nutrition.
- Calves on the moderate plane of nutrition pre-weaning were offered 6L/day containing 750g of milk replacer for 50 days, followed by a two-week weaning period.
- Calves on the higher plane of nutrition were offered 8L/day containing 1,200kg of milk replacer for 14 days, 10L/day containing 1,500g of milk replacer for 24 days, followed by a three-week step-down weaning period.
Throughout this feeding programme, all calves had ad-lib access to concentrate feed pre-weaning.
Post-weaning, from within their respective pre-weaning treatments, calves were allocated to either a moderate (M POST), 1.5kg/day concentrate, or high (H POST), ad libitum concentrate, post-weaning diet for four weeks. Subsequently, all animals were turned out to pasture and managed under a standard 16-month-old pasture based dairy bull beef system blueprint with bodyweight and other measurements collected throughout and carcass characteristics data collected at slaughter.
Results
Commenting on the results of the experiment, available to view in table one below, Jennifer Abbot noted that calves offered the higher plane of nutrition pre-weaning achieved higher average daily gains to weaning, turnout and housing, but this weight difference didn’t follow through until the point of finish, where animals offered the moderate and high pre-weaning planes of nutrition produced similar carcass weight and carcass characteristics at finish.
Table 1: Effect of pre- and post-weaning plane of nutrition (M or H) on performance of dairy-bred bull calves slaughtered at 16 months of age
| Plane of nutrition | Pre-weaning | Post-weaning | Significance | ||||
|---|---|---|---|---|---|---|---|
| M PRE | H PRE | M Post | H Post | SEM | Pre-weaning | Post-weaning | |
| Bodyweight (kg) | |||||||
| Birthweight | 35.3 | 36.9 | 36.4 | 35.9 | 1.07 | NS | – |
| Arrival (3 weeks) | 46.8 | 52.0 | 49.9 | 48.9 | 1.20 | ** | – |
| Weaning (11 weeks) | 83.7 | 92.0 | 87.9 | 87.8 | 1.70 | ** | – |
| Turnout (15 weeks) | 108.8 | 114.5 | 102.0 | 121.3 | 2.00 | * | *** |
| Housing (9 months) | 188.2 | 199.5 | 183.8 | 203.8 | 4.72 | * | ** |
| Bodyweight at slaughter (16 months) | 522.0 | 531.3 | 512.0 | 541.2 | 9.27 | NS | ** |
| Carcass weight | 270.1 | 273.8 | 263.8 | 280.1 | 5.40 | NS | ** |
| Conformation | 5.4 | 4.9 | 5.0 | 5.4 | 0.32 | NS | NS |
| Fat score | 7.2 | 6.6 | 7.1 | 6.7 | 0.45 | NS | NS |
| Average daily gain (kg) | |||||||
| Pre-weaning period (11 weeks) | 0.71 | 0.81 | – | – | 0.024 | * | – |
| Post-weaning period (4 weeks) | 0.91 | 0.84 | 0.55 | 1.20 | 0.040 | NS | *** |
| Grazing period (5 months) | 0.57 | 0.61 | 0.59 | 0.59 | 0.030 | NS | NS |
| Housing to slaughter (7 months) | 1.34 | 1.32 | 1.32 | 1.35 | 0.035 | NS | NS |
Interestingly from a dairy-beef producer’s perspective was the impact of post-weaning feeding strategy on carcass performance, with Jennifer Abbot noting: “Dairy-beef males on the high post weaning plane of nutrition had higher average daily gains than those on the moderate plane of nutrition post weaning, being 19.3kg heavier at turnout, 20kg heavier at housing and 29kg heavier at slaughter, resulting in the production of 16kg heavier carcasses.
“Offering dairy-bred male calves a high plane of nutrition for four weeks post-weaning, irrespective of pre-weaning plane of nutrition, led to enhanced bodyweight gain which was subsequently retained to slaughter at 16 months of age. This also translated to higher carcass weight at slaughter in these animals.”
Concluding her presentation, Jennifer Abbot noted that this study highlights the vital role of optimising post-weaning nutrition to enhance overall lifetime growth and feed efficiency, but further research is needed to refine post-weaning nutritional strategies and evaluate their impact on the economic and environmental efficiency of sustainable pasture-based dairy calf to-beef production systems.
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