Project title: Managing first lactation heifers to maximise welfare and productivity
Team: Alastair Boyle (Proposed PhD student), Supervisors: Drs Niamh O’Connell and Conrad Ferris
Duration: 3 years – commencing June 2008
Organisations involved: AFBI (Hillsborough), Queens University Belfast
Background to and summary of proposal:
The post calving period represents a difficult time for first-lactation dairy heifers, when they experience a number of different challenges simultaneously. In particular, the regrouping of heifers with older cows soon after calving may be particularly stressful, as heifers are often subjected to aggression and bullying. In addition to affecting welfare, these factors may also have a negative effect on health and production performance. It may be possible to reduce these problems by housing heifers separately from the main herd during their first lactation, however housing constraints mean that this is not always a viable option for producers.
The aim of this PhD project is to assess if heifer welfare and productivity can be improved by manipulating the way they are introduced to the main herd. Previous research showed that adding heifers into groups of mature cows as subgroups rather than individuals led to improved welfare and productivity (O’Connell et al., in press). However, this study used small groups of mature cows, which does not accurately reflect commercial practice. One of the aims of the proposed research is to assess if the beneficial effects of adding subgroups, rather than individual heifers, into the main herd are also shown when heifers are added into larger groups of mature cows. The stage at which first-lactation heifers are integrated with the main dairy herd may also influence welfare and productivity. Some farmers mix heifers with dry cows prior to calving for ease of management and to relieve pressure on space, and also to allow heifers to become accustomed to being housed with mature cows prior to lactation. However, other producers are wary of mixing pregnant heifers with older animals in case of injury, and keep these heifers separately until lactation.
This study will assess which strategy – either integrating heifers with the main herd prior to calving or immediately post calving – leads to optimum welfare and productivity in first lactation heifers. In addition, whether or not benefits are shown by integrating heifers with the main herd post peak lactation will also be assessed.
These studies will allow us to assess whether method of introduction, or timing or introduction of heifers to the main dairy herd is more important in affecting welfare and productivity. Data on animal behaviour, milk yield and composition, fertility and lameness will be collected in all studies.
The objectives of the proposed study are:
(1) To assess whether benefits are shown by integrating heifers with the main herd as subgroups rather than individuals
(2) To determine the optimum time scale for integrating heifers with the main herd, i.e. pre-calving, immediately post calving or post peak lactation
1. Review all relevant research in this area
2. Perform trial to assess the effects on welfare and productivity of introducing heifers to the main herd as subgroups rather than individuals (this study will be carried out over two years)
3. Perform trial assessing the relative benefits of integrating heifers with the main herd pre-calving, immediately post calving or post peak lactation.
4. Analyse data and prepare thesis, scientific papers and press releases.
Year 1 Complete literature review and commence Study 1 (individuals versus subgroups)
Year 2 Complete Study 1 and commence Study 2 (timescale of introduction of heifers)
Year 3 Complete Study 2 and produce thesis, scientific papers and press articles
Benefits to Industry
(a) A clearer vision of optimum strategies for managing first lactation heifers
(b) Creating a ‘welfare-friendly’ image within the dairy industry by funding research aimed at promoting both welfare and productivity in heifers
Outputs with timescales
1. Press releases – June 2009, 2010, 2011
2. 2 scientific papers by June 2011
3. Final report to AgriSearch 2011