This project was commissioned by DARD in 2012, as part of the Evidence and Innovation work programme, with co-funding from AgriSearch.
There were four main components to the project.
- A sheep component investigated the longevity, ease of lambing and production performance of a range of composite hill ewe genotypes.
- A beef component examined the performance of native and continental suckler cow genotypes on commercial hill farms.
- A biodiversity component investigated the roles of cattle and sheep grazing for managing biodiversity.
- A fourth component developed tools using Geographical Information Systems (GIS) to identify the optimum grazing capacity for the maintenance and provision of ecosystem services in upland regions of NI.
The project was undertaken on twelve hill farms across Northern Ireland on heather and rush-dominated habitats grazed by either sheep or cattle.
Data from 2,850 composite ewes, born between 2007 and 2012 were obtained from 6 hill farms. Replacement ewes were obtained following two contrasting strategies applied at all study farms: a criss-cross (CC) between Blackface and Swaledale rams or a three-breed (3B) rotation combining Lleyn or Belclare, Highlander and Texel rams.
- Mature 3B ewes were heavier than CC ewes (61.5 kg vs 57 kg), but had lower Body condition scores (BCS) (3.6 vs 3.8).
- Conception rate was high, with an average of 0.95 across all ewe types, regardless of breed or age.
- Weaning rates were similar regardless of breeding strategy (1.36 lambs weaned per ewe lambed at 4.5 years old), despite highest weaning rates for Highlander x ewes (+0.25 lambs).
- Overall ewe efficiency (kg lamb/kg ewe) was similar regardless of breeding strategy (benefit of slightly heavier lambs from 3B cancelled out by higher ewe live weight).
A total of six suckler producers were recruited via AgriSearch to be involved with this study located within counties Tyrone, Fermanagh and Antrim. Cows were identified as either continental or native according to their registered breed type and phenotype.
- Continental genotypes were significantly heavier than native genotypes, however limited differences in body condition scores were observed between the two genotypes.
- Native genotypes had more cows classified as “very quiet” at calving and in year 1 had more cows calving “unassisted” relative to continental genotypes. However, calving difficulty was similar across genotypes during year 2.
To identify the impact of environment on suckler herd fertility, data was extracted from a Suckler Herd Fertility Survey undertaken by AFBI on 105 farms in conjunction with CAFRE during autumn 2012 and spring 2013.
- Fertility of suckler cows in hill environments was lower than lowland environments, regardless of genotype.
A total of eight farms were used for the vegetation study, four sheep and four beef farms. Five of the sites were managed under DARD Countryside Management Scheme agreements. Within each of the sites (i.e. management units or fields), a maximum of four grazing exclosures were put up in pre-selected areas.
Detailed habitat/vegetation maps of the study sites were produced by a field mapping survey in conjunction with use of recent orthographic images. Vegetation height, plant species composition and biomass were recorded during the periods July-October 2013 and May-October 2014.
- Over the short-time period of this study, there was little evidence that livestock (sheep or cattle) had grazed late building or mature heather during the summer sampling periods.
- Sheep and cattle were shown to have a strong preference for newly burnt heather over older age classes.
- There was no evidence of sheep or cattle grazing soft rush where it was present.
- With the exception of purple moorgrass in some circumstances, there was little evidence that sheep (or cattle) were grazing on other dominant moorland graminoid species, i.e. cotton grasses or deer grass.
- As study farms generally had drier semi-improved or acid grassland areas available, these were preferentially grazed by sheep. This meant that heather or rush-dominated areas were only occasionally utilised.
A GIS methodology was successfully developed and applied to Northern Irish uplands to explore the relationship between grazing capacity and a range of ecosystem services (biodiversity, soil and water quality). To illustrate this, new maps were produced to estimate the potential risk posed to water quality due to grazing. This methodology is now available to better inform land use management.
In light of the main findings of this study and recent discussions with DARD advisors, policy and industry stakeholders, several important implications were identified for policy and industry.
- In particular, only limited pressure was found of grazing livestock on vegetation structure, which suggests that stocking rates and/or grazing periods may not be appropriate.
- Grazing prescriptions may have in some cases contributed to the presence of stands of tall heather, potentially becoming ineligible for SFP.
- Site-specific prescriptions may be necessary to ensure that heather or rush dominated areas are more utilised by sheep and cattle.
During the preparation and implementation of this work, and subsequent analyses of the animal and vegetation data, a number of evidence gaps were identified and summarised in this report.
The Full report, "Development of beef and sheep systems for improved sustainability, biodiversity and delivery of ecosystem services within hill areas of Northern Ireland" (Project 12/4/08) by Aurélie Aubry, Melanie Flexen, Francis Lively, Denise Lowe, Alex Higgins, Rachel Cassidy, Donnacha Doody is available here