Optimum Grazing Systems for Youngstock (PhD)

Summary

Rearing a dairy heifer costs £1800-2,000 or >6ppl of milk produced.  Calving at the optimum weight and age has been shown to result in improved fertility, longevity and lifetime performance.  However, the average age at 1st calving in the UK is still estimated to be over 30 months (beef and dairy).  Reasons for producers failing to calve heifers at 24 mths include:

• Lack of monitoring equipment on farms
• Producer uncertainty over the longevity of heifers that first calve at 24 months of age
• Lack of precise information/nutritional guidance to assist producers to achieve target growth
• Inability to deliver nutritional programs individually to heifers depending on performance
• No real time delivery of performance and guidance data

Key Findings:

• Weight and body condition score of the heifer entering the milking herd will affect first and subsequent lactation potential.  
• Cost of maintaining the pregnant heifer decreased by £1.75 for every extra day at grass.  

Aims and Objectives

The aim of this study was to provide a better understanding of the role and potential of grazed grass within heifer-rearing systems. A series of grazing studies will be conducted to address the identified knowledge gaps utilising cutting edge individual behaviour monitoring systems, novel grazing strategies and remote automated concentrate and livestock weighing equipment in the field. Project findings will guide producers in both maximising livestock growth from grass and grassland utilisation.  This will lead to the development of rearing blueprints for grazing heifer replacements designed to control costs and achieve growth targets to calve at 24 months of age. A wide range of knowledge exchange techniques will be used during the project including farm walks, website publications/software, conferences and scientific papers. 

• Consider the strengths and weaknesses of grazing systems and practices 
• Address the weakness through incorporating precision technologies, e.g. remote concentrate-feeding systems and possibility of weighing remotely (CIEL Investment) 
• Establish the optimum pasture allowance for replacement heifers in order to both optimise animal performance and pasture growth and utilisation 
• Develop grazing wedges for grazing dairy heifer replacements 
• Better understanding of grazing strategies for heifers and how best to meet targets, leading to increased efficiencies and profits 
• Improving rearing efficiency to enable heifers to fulfil their genetic potential will also directly impact sustainability and profitability