Nutrition of the Aged Horse

Rice bran in old horse’s nutrition and their influence on condition, blood biochemical parameters, total feces bacteria and methanogen population

This study aimed to verify whether the inclusion of 0.5 kg full-fat rice bran per day in the diet of geriatric horses will improve their condition, increase the population of methanogens in the cecum, and thus affect the biochemical blood parameters. The experiment assumed 2 research periods: 6 healthy, non-working horses over 20 years of age (480 ± 20 kg of body weight) were fed only hay (±8.86 kg/day/head) in the first period and hay (±8.00 kg/day/head) and rice bran (0.5 kg/day/head) in the second one. Each of these periods lasted 4 months. The Body Condition Scoring (BCS) assessment was performed at the beginning and end of the experiment. Blood and feces samples were collected on the first and last day of each period. After feeding with the addition of rice bran, BCS increased by 1.17 units on a 9-point scale. The experiment showed an increase in the total number of bacteria and methanogens inhabiting the cecum of horses. This can lead to better digestion of carbohydrates, absorption of nutrients, and, consequently, increased body weight. No differences occurred in the hematology and serum biochemistry indices of horses fed a diet including rice bran, except for the amount of serum globulin and the albumin to globulin ratio. Rice bran affected essential serum fatty acid profile (increased PUFA and decreased MUFA) which confirmed the possibility to use diet as a serum fatty acids profile modulator.

How to Perform a Nutritional Assessment in a First-Line/General Practice

Inappropriate nutrition is a priority welfare challenge. Nutritional mistakes are common and can lead to adverse events, such as poor growth and performance, colic, laminitis, and obesity. A detailed nutritional assessment involving evaluating the equine patient, current diet/ration, and management is essential in creating an effective nutritional plan. Goal(s) should be established and used to inform the plan. Management or resource barriers should be considered. Effective communication and a team-based approach versus an authoritarian one are likely to enhance the success of the nutritional plan. Developing a plan should be an interactive process, adjusting as needed after intentional monitoring.

Nutritional Considerations when Dealing with an Underweight Adult or Senior Horse

Weight loss occurs when the supply of energy is insufficient to meet the energy needs of an individual. The energy supply may be reduced by inadequate provision of feed, inadequate consumption, reduced digestion and absorption, or disruption in metabolic processing. Increased energy expenditure occurs with exercise and during cold temperatures, pregnancy, and lactation. Underlying clinical disease, particularly chronic inflammation, neoplasia, and protein-losing conditions, can cause weight loss or exacerbate existing weight loss. A methodical approach to weight-loss investigation and treatment is necessary, because of the often multifactorial nature of this condition.

Exercise training, Glut-4 protein abundance and glutamine in skeletal muscle of mature and very old horses

Two groups of unfit Standardbred mares (adult: 9-14 years, 540 kg, n=7) and old (20-25 years, 530 kg, n=5) were used to test two hypotheses, first, that aging and training would alter plasma and muscle glutamine [Gln] and glutamate [Glu] and second, that aging and training would alter Glut-4 expression in skeletal muscle. All animals were housed on pasture with free access to grass and all received hay and supplementation with a commercially prepared supplement (15% crude protein and 3.00 Mcal/kg dry matter) in individual stalls. Mares were fed to meet or exceed NRC (2007) nutrient recommendations for moderate to heavy exercise. The mares were exercise trained in a free-stall motorised circular exercise machine for 30 min/d, 5 d/week, for 8 weeks. Work intensity during training was set at a relative intensity of ~60% of the maximum heart rate, previously determined during an incremental exercise test (GXT). Blood samples and muscle biopsies (gluteus) obtained before and after 8 weeks of training were used for measurement of [Gln], [Glu] and Glut-4 abundance. Samples were collected before the initiation of training and at 24 h after cessation of last bout of exercise in the training period. All samples were immediately frozen in liquid nitrogen and stored at -80 °C until enzymatic analysis for [Gln], [Glu] and Western Blot analysis for Glut-4 protein abundance. Data were analysed by one-way or two-way ANOVA for repeated measures and the Pearson correlation method. Post-hoc differences were identified with the Tukey test. Significance was set at P<0.05. There were no differences (P>0.05) in muscle [Glu] due to aging. Training decreased (P<0.05) muscle [Glu] from 7,561±701 nmol/g of tissue (mean ± standard error) in pre-training samples to 4,491±701 nmol/g of tissue post-training. Plasma [Gln] decreased (P<0.05) with training (368±14 nmol/ml vs 317±14 nmol/ml). There was a trend (P=0.063) towards an effect of aging. There were significant interactions between age and training for plasma [Gln]. Old mares had lower (P<0.05) post-exercise plasma [Gln] (224±21 nmol/ml) when compared with pre-exercise plasma [Gln] (372±21 nmol/ml). Post-training, plasma [Gln] was lower (P<0.05) in the old mares compared to adult mares [Gln] (224±21 nmol/ml vs 410±18 nmol/ml). There was an effect (P<0.05) of age on muscle [Gln] (old = 6,126 ±870 nmol/g of tissue; adult = 3,176±735 nmol/g of tissue); however, there were no changes (P>0.05) due to training. Glut-4 abundance analysis did not differ (P>0.05) between the young adult and old horses; however, there was a trend (P=0.063) towards an effect of training when samples from both groups were pooled. It was concluded that training and aging produce changes in plasma and muscle [Gln], which may affect immune function in athletic horses, but not in Glut-4.

Welfare of Aged Horses

Simple Summary

Horses form a unique and special part of their owners' lives and aged horses are no exception. This review considers the health and management of aged horses. In particular how owners manage and care for their aged horses, what diseases and conditions they suffer from and what factors affect their quality of life. As an aged horse reaches the end of its life, an owner will be faced with judging its quality of life and making the decision to end its suffering. The veterinary surgeon plays an essential role in supporting the owner in this process.

Abstract

Horses form a unique and special part of their owners' lives and aged horses are no exception. This review considers the health and management of aged horses, including the role of the owner and their perceptions of aged horses, potential threats or risks to their welfare and finally, factors affecting quality of life and euthanasia of aged horses. Owners of aged horses are concerned about the health, welfare and quality of life of their aged animals. Yet surveys of management and preventive healthcare reflect that there may be some limitations to what owners are actually achieving in practice. They show declining management as horses age, particularly for the retired horse and insufficient appropriate preventive healthcare via veterinary surgeons. The veterinary surgeon plays an essential and influential role in preventive healthcare, management of diseases and disorders and ultimately in the decision making process for euthanasia of aged horses at the end of their lives. The value of aged horses should not be underestimated by veterinarians and others working with them and the continuing care of aged horses should be regarded with the same importance as the care of younger horses with more obvious monetary value.