PhD in Veterinary Sciences for Animal Health and Food Safety

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Supervisor

Phd thesis

Not enough effort is being made to safeguard the welfare of horses reared for meat production. Moreover, there is a lack of scientific knowledge concerning the welfare of horses reared in this way. These horses are often kept in intensive breeding farms where they are housed in group pens at high stock densities and fed high starch diet. The present PhD project aimed to apply an integrated approach to the evaluation of the welfare and management in the equine meat farm. The integrated approach was developed considering several aspects – welfare indicators, gut health, behaviour, production performances – which were investigated according to two main aims.

The first aim of the present PhD project was to obtain insight into the housing and management welfare conditions of horses reared for meat production and to evaluate whether the selected welfare indicators and behavioural activities were influenced by the main causes of concern that regard intensive breeding farms: stocking density and feeding management. The results obtained revealed that stocking densities and feeding management influenced welfare indicators of horses reared in group pens for meat production and thus constitute key concerns. The results suggest that horse welfare is negatively affected by high stocking densities and the use of an intensive feeding management strategy. According to the results obtained, when the horses had more than 4.75 m²/horse, many parameters were influenced (i.e., improvement of coat cleanliness, improvement of bedding quantity, improvement of the mane and the tail condition, less resting in a standing position and less feeding related to the greater space available at the feed bunk). Moreover, horses were fed rations rich in starch, which was probably responsible for the high incidence of diarrhoea and, consequently, the poor state of bedding cleanliness. Therefore, a further increment of space and changes in feeding management resulted necessary to improve the welfare status of horses reared for meat purpose.

The role of the stocking density was further studied investigating the effects of different stocking densities on the behavioural activities of the horses reared for meat purpose and subsequently on their welfare. Although the horses reared for meat production expressed an unusual time-budget, since, compared with wild-living horses, significantly more time was spent lying down and less time was dedicated to feeding and locomotion activities; the reduction in stocking density and as a consequence a space allowance of 6 m²/horse had a positive impact on the expression of some behaviours – locomotion, playing, and self-grooming – which could be proposed as indicators of positive welfare in young horses kept in group pens.

The second aim of the present PhD project was to evaluate the effects of two feeding managements (on based on high amounts of starch vs. one based on high amounts of fibre) on gut health, behaviour and production performances in horses reared for meat production.

Regarding the gut health, the HS diet was found to have a profound effect on the horse’s gut environment in terms of dry matter (DM), volatile fatty acids (VFAs) production and particle sizes as well as on the horse’s gastrointestinal barrier in terms of severity of gastric mucosa lesions, gut histo-morphometry and intestinal permeability.

A higher DM content in the right dorsal colon, a higher ash content and higher production of VFAs in all the analysed hindgut compartments were found in the horses fed the HS diet compared with horses fed the HF diet. Not only were total VFAs higher in the HS group, but differences in the VFA composition was also noted. In particular, the valeric acid was increased in horses receiving the HS diet, and this should be explored in more depth since this VFA has already been implicated in causing alterations to the gastric mucosa. In fact, the results obtained demonstrated that the HS diet was associated with the presence of more severe mucosa gastric lesions in the glandular region of the stomach and a higher lymphoplasmacytic inflammation in the jejunum and pelvic flexure; instead no differences were found regarding the histo-morphometry of duodenum, jejunum and ileum compared to the HF diet. Moreover, the results obtained supported the notion that feeding horses high amounts of starch can lead to a condition of increased intestinal permeability. In summary, the results of this study confirm that the diet composition, and thus feeding management practices, are able to influence the gut environment and its functioning.

Regarding the behavioural activities of horses reared for meat production according to the two dietary treatments (HS vs. HF), the present PhD project showed that the behavioural changes by feeding horses with a HF diet indicated increased welfare, according to the increased expression of the feeding behaviour and the reduced frequencies of standing and locomotion. Moreover, the HF feeding management resulted in a lower expression of stereotypic behaviour and biting. In summary, the change in feeding management from a HS diet to a HF diet in horses reared for meat production led to advantage on the horse’s welfare since horses fed the HF diet showed less aggressive and stereotypic behaviours as well as on the economic point view since horses fed the HF diet were less engaged in by locomotion – so, spending less energy – and more occupied in feeding behaviour.

Accordingly, regarding to the production performances, the HS diet resulted wasteful from an economic stance since it did not result with any difference in daily bodyweight gain or with any positive effect on muscle characteristics. In fact, horses in HS showed increased muscle pH, lighter muscle colour, lower muscular protein content increased intramuscular fat concentrations but lower concentration of muscle polyunsaturated fatty acids (PUFAs) compared to the horses in HF. Moreover, the PhD study showed that diet influenced the concentrations of glutathione peroxidase, catalase and superoxide dismutase; although plasma, muscle and liver were characterised by distinct differences. Interestingly, the higher plasmatic catalase found in horses belonging to HF suggest that the animals were more protected by oxidative damages.

Research activities

Articles related to the PhD project
1. Raspa, F.; Dinardo, F.R.; Vervuert, I.; Bergero, D.; Bottero, M.T.; Pattono, D.; Dalmasso, A.; Vinassa, M.; Valvassori, E.; Bruno, E., De Palo, P.; Valle, E. A Fibre- vs. cereal grain-based diet: Which is better for horse welfare? Effects on intestinal permeability, muscle characteristics and oxidative status in horses reared for meat production. Journal of Animal Physiology and Animal Nutrition. 2021, 00, 1–14
2. Raspa, F.; Tarantola, M.; Bergero, D.; Bellino, C.; Mastrazzo, C.M.; Visconti, A.; Valvassori, E.; Vervuert, I.; Valle, E. 2020. Stocking Density Affects Welfare Indicators in Horses Reared for Meat Production. Animals., 2020, 10, 1103
3. Raspa, F.; Tarantola, M.; Bergero, D.; Nery, J.; Visconti, A.; Mastrazzo, C.M.; Cavallini, D.; Valvassori, E.; Valle, E. 2020. Time-Budget of Horses Reared for Meat Production: Influence of Stocking Density on Behavioural Activities and Subsequent Welfare. Animals., 2020, 10, 1334

Articles not related to the PhD project
4. Raspa, F.; Roggero, A.; Palestrini, C.; Canavesio, M.M.; Bergero, D.; Valle, E. Studying the Shape Variations of the Back, the Neck, and the Mandibular Angle of Horses Depending on Specific Feeding Postures Using Geometric Morphometrics. Animals., 2021, 1–15
5. Tassone, S.; Fortina, R.; Valle, E.; Cavallarin, L.; Raspa, F.; Boggero, S.; Bergero, D.; Giammarino, M.; Renna, M. Comparison of In Vivo and In Vitro Digestibility in Donkeys. Animals., 2020, 10, 2100
6. Vinassa, M.; Cavallini, D.; Galaverna, D.; Baragli P.; Raspa F.; Nery, J.; Valle, E. Palatability assessment in horses in relation to lateralization and temperament. Applied animal behaviour science., 2020, 232
7. Raspa, F.; Cavallarin, L.; McLean, A. K.; Bergero, D.; Valle, E. A Review of the Appropriate Nutrition Welfare Criteria of Dairy Donkeys: Nutritional Requirements, Farm Management Requirements and Animal-Based Indicators. Animals., 2019, 9, 315

Abstracts on international congress related to the PhD project
1. Raspa F., Tarantola M., Bergero D., Valvassori E., Mastrazzo C.M., Visconti A., Valle E., 2019. A preliminary study on the behaviours of horses reared for meat production: effect of the space available on daily activity budget. 23th Congress of the European Society of Veterinary and Comparative Nutrition, Torino, 18-20 settembre, 89 p.
2. Raspa F., Tarantola M., Bergero D., Bellino C., Valvassori E., Mastrazzo C.M., Visconti A., Valle E., 2019. A preliminary study on the welfare of horses reared for meat production: how the space available affects the welfare parameters of appropriate nutrition. 23th Congress of the European Society of Veterinary and Comparative Nutrition, Torino, 18-20 settembre, 90 p.
3. Raspa F., Cavallini D., Vervuert I., Valvassori E., Mammi L.M.E., Bergero D. Valle E. 2020. Impact of two different diets on faecal parameters of horses. 24th Congress of the European Society of Veterinary and Comparative Nutrition On line 17-20settembre, 96 p.
4. Raspa F., De Palo P., Vervuert I., Bergero D., Valvassori E., Valle E. 2020. Antioxidant enzymes and oxidative stress end products in horses fed with different feeding strategie. 71th EAAP Virtual Annual Meeting 1-4 dicembre, Theatre session 39, 415 p.
5. Raspa F., Vervuert I., De Palo P., Cavallini D., Bergero D., Valvassori E., Valle E. 2021. Influence of two feeding managements on behaviour and welfare in horses reared for meat production. 72th EAAP Annual Meeting, Davos (Switzerland), 30 agosto-3 settembre, Theatre session 28, 308 p.
6. Raspa F., Colombino E., Capucchio M.T., Cavallini D., Vervuert I., Bottero M.T., Pattono D., Dalmasso A., Bergero D., Valvassori E., Valle E. 2021. Effects of feeding managements on microbial contamination of mesenteric lymph nodes and liver and on intestinal histo-morphology in horses. 25th Congress of the European Society of Veterinary and Comparative Nutrition On line 9-11 settembre, 93 p.

Abstracts on international congress not related to the PhD project
7. Raspa F., Valle E., Bergero D., Addamo G., Paonessa F., Virone G., 2019. A preliminary study on the feasibility of using microwave frequencies to determine several tissue samples from horses. 23th Congress of the European Society of Veterinary and Comparative Nutrition, Torino, 18-20 settembre, 169 p.
8. Cavallini D., Pagliara E., Raspa F., Valle E., 2019. Cases of stomatitis induced by Setaria glauca and Echinochloa crus-galli in horses. 23th Congress of the European Society of Veterinary and Comparative Nutrition, Torino, 18-20 settembre, 171 p.
9. Raspa F., Vergnano D., Cavallarin L., Mclean A., Tarantola M., Valle E., 2019. Meeting nutritional needs to ensure dairy donkeys’ welfare. 70th EAAP Annual Meeting, Ghent, 26-30 agosto.

Awards
EAAP (European Federation of Animal Science) Scholarship Winner within the 72nd EAAP Annual Meeting, Davos, Switzerland – Title: “Influence of two feeding managements on behaviour and welfare in horses reared for meat production

Stays abroad
1/02/2020 – 16/03/2020: Institute of Animal Nutrition, Nutrition Diseases and Dietetics, Faculty of Veterinary Medicine, Leipzig University under the supervision of Professor Ingrid Vervuert.