Alternative finishing strategies for Holstein-Friesian bulls slaughtered at 15 months of age

Brian Murphy,Alan K Kelly,Robert Prendiville

doi:10.23986/afsci.66719

Brian Murphy, Alan K Kelly + Show 1 more

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https://doi.org/10.23986/afsci.66719

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Abstract

The aim was to establish the optimum finishing strategy (FS) for dairy bulls slaughtered at 15 months. Sixty spring-born calves were assigned to one of four FS. The FS were split into two phases; pasture (PAS) from mid-August to housing (P1) and finished indoors on concentrates ad libitum plus straw for 209 d (P2). Treatment 1 (T1) was offered PAS in P1 and 800 g kg-1 barley (BAR), 140 g kg-1 soya bean meal (SBM), 40 g kg-1 molasses and 20 g kg-1 minerals (B) in P2. Treatments 2 (T2) and 3 (T3) were offered 3 kg dry matter (DM) of B per head daily at PAS. In P2, T2 was offered B while T3 was offered 400 g kg-1 BAR, 400 g kg-1 maize meal, 140 g kg-1 SBM, 40 g kg-1 molasses and 20 g kg-1 minerals (BM). In P1 treatment 4 (T4) was offered 3 kg DM of BM per head daily at PAS and 750 g kg-1 BAR, 140 g kg-1 SBM, 50 g kg-1 rumen protected fat, 40 g kg-1 molasses and 20 g kg-1 minerals in P2. Finishing strategy did not affect lifetime average daily gain or carcass conformation. Fat score tended (p=0.0514) to be greater for T3 than T1 and T4.

Highlights

Bull beef production systems have the potential to increase carcass output per hectare by slaughtering animals at a younger age and produce less greenhouse gas (GHG) emissions than steer beef systems (Nogalski et al 2014, Murphy et al 2017a)
Moderate levels of performance are common for male dairy calves at pasture during the first grazing season in Ireland which is attributed to the blueprint for the traditional 24 month steer production system (Keane and Allen 1998)
Calves were turned out to pasture on 24 April and offered 1 kg dry matter (DM) per head daily of a calf ration (350 g kg-1 barley; 140 g kg-1 soya hulls; 120 g kg-1 soya; 100 g kg-1 rapeseed meal; 90 g kg-1 molasses; 80 g kg-1 flaked maize; 50 g kg-1 wheat distillers; 50 g kg-1 beef pulp and 20 g kg-1 minerals)

Summary

Introduction

Bull beef production systems have the potential to increase carcass output per hectare by slaughtering animals at a younger age and produce less greenhouse gas (GHG) emissions than steer beef systems (Nogalski et al 2014, Murphy et al 2017a). Animals slaughtered at a younger age require concentrate intensive finishing diets to ensure an acceptable carcass at slaughter (O’Riordan et al 2012). Integrating a greater proportion of grazed grass in the diet reduced feed costs (Ashfield et al 2014), intensive young bull production systems require high levels of concentrates to ensure optimum animal performance throughout the animal’s lifetime. Male dairy calves managed in young bull systems in the UK are typically housed indoors on a concentrate intensive diet where little/no grazed grass is incorporated into the feed budget (Meat Promotion Wales 2014). Moderate levels of performance are common for male dairy calves at pasture during the first grazing season in Ireland which is attributed to the blueprint for the traditional 24 month steer production system (Keane and Allen 1998)

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