Abstract
Fully slatted concrete flooring is a popular floor type used to accommodate beef cattle in Northern Ireland (Nl). Concrete slats have many benefits for the producer, including facilitating more efficient slurry management and a higher stocking density than when bedded systems are used. However, previous research has associated this type of flooring with hoof problems, slipping and leg injuries in beef cattle. The Nl beef industry is now under increasing pressure from both consumers and retailers to move away from these systems on animal welfare grounds.A literature review undertaken in Chapter 1 of this thesis suggested that the welfare of beef cattle was highest on solid floors with straw bedding, followed by rubber covered slats and then concrete slats. However, much of this research was conducted using intensively finished young bulls and not in the grass-based systems typically used in Nl. This review also highlighted concerns regarding the use of rubber flooring as an alternative to concrete slats, due to insufficient hoof wear having a negative impact on hoof health.
One of the aims of the research in this thesis was to fully evaluate alternative viable solutions to concrete slatted flooring for beef cattle that are part of grass- based production systems in Nl. An initial survey of floor types used on Nl beef farms reported in Chapter 2 confirmed that fully slatted concrete flooring is the most common floor type used in Nl, followed by rubber covered slats and then a bedded system. The results presented in Chapter 2 showed that the main reasons farmers chose to accommodate their beef cattle on a fully slatted concrete floor was ease of management, including slurry management, and improved animal cleanliness. Finance was also an important consideration in choosing to cover fully slatted concrete flooring with rubber. This suggests that in order to see large scale adoption of alternative floor types to concrete slats, they need to be labour efficient and improve animal performance to regain some of the additional costs associated with such systems.
The findings of Chapter 2 also indicated that a third of beef producers took part in schemes which provided a financial incentive to accommodate beef cattle for at least three months prior to slaughter on rubber covered slats or a bedded system. However, there is limited scientific evidence that this system improves animal performance and welfare. Therefore, Chapters 3 and 4 investigated the effect of using a combination of floor types throughout both the growing and finishing periods on beef cattle performance, cleanliness, carcass characteristics, meat quality and hoof health. The floor type treatments studied included a fully slatted concrete floor throughout the entire experimental period (CS); rubber covered slats throughout the entire experimental period (RS); fully slatted concrete flooring during the growing period and a solid floor covered with straw bedding during the finishing period (CS-S), and fully slatted concrete flooring during the growing period and rubber covered slats during the finishing period (CS-RS). Results presented in Chapter 3 showed no overall effect of treatment on animal performance, cleanliness at slaughter, carcass characteristics or meat quality. Additional behavioural data presented in Appendix 2 demonstrated improved lying and standing behaviour, indicative of improved welfare, in finishing bulls accommodated on straw bedding, followed by rubber covered slats and then concrete slats. However, accommodating beef cattle on a fully slatted concrete floor during the growing period had no detrimental effect on animal performance or behaviour. The findings reported in Chapter 4 showed that accommodating bulls on RS reduced the probability of bruised soles. Furthermore, despite greater toe net growth in bulls accommodated on rubber covered slats, there was no evidence to suggest that this negatively impacted hoof health. In addition, although bulls accommodated on straw bedding had a lower mean maximum hoof temperature compared with those accommodated on any other floor type, there was no evidence to suggest improved hoof health.
A further broad aim of this thesis was to determine whether penalties that are imposed when Nl beef cattle have had greater than four farm residencies during their lifetime are justified. Currently, there is no scientific basis for this imposed residency specification and the issue has been controversial amongst beef producers. Therefore, industry data collected at slaughter was used to investigate the effect of breed and the number of animal movements between farms on the lifetime performance of beef cattle in Nl. The findings of Chapter 5 highlighted that cattle that complied with the residency specification had improved daily carcass gain and were slaughtered earlier compared with those that failed to meet this specification. This suggests that penalties to discourage animal movements are, in fact justified, with poorer lifetime performance possibly indicating a worsened animal welfare state. Further research exploring additional performance data captured as beef animals move through livestock markets would be beneficial to more fully investigate the effect of breed and the duration of the last farm residency on the performance of Nl beef cattle.
The survey conducted in Chapter 2 also found that most Nl beef producers grouped cattle according to estimated size. There is relatively little research with beef cattle on the effects of different methods of group formation, therefore the aim of Chapter 6 was to investigate the effect of grouping finishing bulls with a low versus a high within-pen variation in live weight on animal performance and welfare. Results showed that grouping animals with dissimilar live weights tended to decrease fighting duration and improve performance. This research was conducted under conditions where competition for resources was limited, and further research investigating different grouping strategies with larger group sizes and under more competitive conditions is warranted.
Overall, the research conducted in this PhD enabled important data on current industry practices in relation to floor type, animal movements and regrouping strategies used on Nl beef farms to be collated. The data presented supports the move by a number of producers to use rubber covered slats for beef animals during the finishing period on welfare grounds, and also supports the penalties currently being applied to discourage animal movements between farms. With the average beef animal in Nl experiencing two farm residencies prior to slaughter, further research investigating different grouping strategies to minimise the negative effects of social stress would be beneficial to the industry.
| Date of Award | Dec 2019 |
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| Original language | English |
| Awarding Institution |
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| Sponsors | Department of Agriculture, Environment and Rural Affairs |
| Supervisor | Denise Lowe (Supervisor), Francis Lively (Supervisor) & Niamh O'Connell (Supervisor) |
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