T. Hollands

Effect of feeding increasing quantities of starch on glycaemic and insulinaemic responses in healthy horses

The aim of this study was to investigate the effect of increasing the intake of starch on the glycaemic and insulinaemic responses of horses. A cross-over study design was used in which four horses were fed increasing amounts of a compound feed (0.5-3.5 kg) to provide 0.3, 0.6, 0.8, 1.1, 1.4 and 2 starch/kg bodyweight (BW)/meal. The glycaemic response increased with starch intake (P<0.05), while feeding <1.1 g starch/kg BW resulted in a lowered response, compared to when 1.1-2 g starch/ kg BW was fed (P<0.01). The results suggested that insulin responses may be more appropriate to define the effect of feeding different starch levels than glycaemic responses. A starch intake of <1.1g/kg BW/meal produced only moderate glucose and insulin responses, even though highly processed cereals were used. It is therefore recommended that a starch intake of <1.1 g/kg BW/meal or a meal size of 0.3 kg/100 kg BW (starch content of 30-40%) is used for horses.

Accuracy of different methods of estimating the weight of horses.

Six hundred horses of different ages, heights and breeds were weighed on a weighbridge and had their weights estimated by two weigh tapes, 1 and 2, by a formula, and by a visual estimate. For the population as a whole, the most accurate method was the formula (mean [sd] 98.6 [10.61 per cent) closely followed by weigh tape 2 (98.1 [8.1] per cent). Tape 1 and the visual estimate were the least accurate (112.0 [9.3] and 88.3 [20.1] per cent respectively). When the population was divided into two height groups, the formula and weigh tape 2 were the most accurate for horses <15 hh (99.6 [5.2] per cent and 99.0 [5.6] per cent respectively), and weigh tape 1 and the visual estimate were 113.5 (6.5) per cent and 88.4 (16.3) per cent accurate respectively. For horses ≥15 hh weigh tape 1 was most accurate (103.5 [9.1] per cent) and the formula, tape 2 and the visual estimate were 95.5 (13.1) per cent, 91.8 (9.2) per cent, and 89.3 (22.2) per cent accurate respectively. Overall the formula appeared to be the most accurate estimator of a horses weight. However, owing to individual variation, it is recommended that the weights of horses <15 hh are estimated by the formula or weigh tape 2, and that the weights of those ≥15 hh are estimated with weigh tape 1.

Validating the alkane pair technique to estimate dry matter intake in equids

The estimation of dry matter intake (DMI) using the alkane pair technique has been validated in ruminants, but not in equids. The current paper reports the finding of three comparative validation studies carried out using a total of 12 cattle, 29 donkeys and 10 horses during which directly measured intake was compared to estimated intake using the alkane pair technique. Two methods were developed to dose the even chain alkanes that were used as external markers. Study I, carried out in Zimbabwe, compared the accuracy of estimated intake with measured intake in cattle and donkeys using hexatriacontane (C36) as the external marker. Studies II and III were carried out in the UK with horses and donkeys and compared the accuracy of estimated intake with measured intake using dotriacontane (C32) as the external marker. Study III also tested the effect on the accuracy of intake estimates of two marker dosing levels (mean daily dose of 224 mg per animal and 448 mg per animal) and two dosing frequencies (2

The effect of mixing and changing the order of feeding oats and chopped alfalfa to horses on: glycaemic and insulinaemic responses, and breath hydrogen and methane production.

The aim of this study was to investigate the effects of feeding oats alone before or after feeding chopped alfalfa or, in admixture with the alfalfa on the glycaemic and insulinaemic responses of horses as well as post-prandial breath hydrogen and methane excretion. Horses were fed in a randomized order, chopped alfalfa as a source of dietary fibre and unprocessed oats as a source of starch. Chopped alfalfa intake was adjusted to a crude fibre intake of 0.5 g/kg bodyweight (BW) per meal and the oats intake was adjusted to a starch intake of 2 g/kg BW per meal. The feeds were offered in three different ways: (i) alfalfa followed by oats (A/O), (ii) oats followed by alfalfa (O/A) or (iii) a mixture of alfalfa and oats (A + O). Oats alone were used as a control. Blood and breath were collected after the test meal was fed at the end of a 11.5-h overnight fast following a 10-day acclimatization period. The highest glycaemic and insulinaemic responses were measured when the A/O and O/A diets orders were fed, whereas most hydrogen was produced after feeding oats alone. It was concluded that adding alfalfa chaff to a meal of oats prolonged the pre-caecal digestion of starch, but there was no evidence for any effect on pre-caecal starch digestibility.

Effects of processing barley on its digestion by horses

Four horses were randomly fed a diet containing rolled, micronised or extruded barley; the barley intake was adjusted to supply 2 g starch/kg bodyweight per day. During a 10-day acclimatisation period the horses were also fed 1 kg grass hay/100 kg bodyweight per day. Samples of blood and breath were collected at the end of each period after the test meal of barley had been fed after a 12-hour overnight fast. The glycaemic and insulinaemic responses of the horses were measured as an indication of the pre-caecal digestibility of starch, and postprandial breath hydrogen and methane were measured to detect microbial fermentation of starch. The highest peak serum glucose and serum insulin concentrations were observed after feeding the extruded barley, lower concentrations were observed after feeding the micronised barley and the lowest concentrations were observed after feeding the rolled barley. Breath hydrogen increased within four hours of feeding all the barley diets, and the mean (sd) peak hydrogen concentrations were 98·3 (55·2) ppm for rolled barley, 59·3 (31·5) ppm for micronised barley and 96·1 (51·9) ppm for extruded barley. There were wide variations within individual horses but these concentrations were not significantly different. Breath methane concentrations were very variable and, although there were no significant differences, there was a trend for higher methane concentrations after the feeding of rolled barley.

The use of nutritional supplements in dressage and eventing horses

The aim of the study was to determine which types of nutritional supplements were used in dressage and eventing horses, and the reasons that owners used supplements. An online questionnaire was distributed through British Eventing and Dressage websites, to collect data on demographics of owners and their horses, supplements used and their opinion on health and performance problems. Data were evaluated using descriptive analysis, Sign and Fishers exact tests for quantitative data, and categorisation of qualitative data. In total, 599 responses met the inclusion criteria (441 dressage and 158 eventing horse owners). Participants had 26.4 (3–60) (mean (range)) years of riding experience, owned 1.2 (0–10) horses and used 2 (0–12) supplements in their highest performing horse. The main health and performance issues identified for dressage were ‘energy/behaviour’, ‘lameness’ and ‘back and muscle problems’. The main issues for eventing were ‘stamina and fitness levels’,’ lameness’ and ‘energy/behaviour’. The main reasons for using supplements in their highest performing horse were ‘joints and mobility’, and ‘behaviour’ for dressage, and ‘electrolytes’, and ‘joints and mobility’ for eventing. Lameness and behavioural problems were significant concerns within both disciplines. There was incongruence between owners’ opinions of problems within their discipline and their reasons for using supplements.

Use of height-specific weigh tapes to estimate the bodyweight of horses.

Two thousand horses of different ages, heights and breeds were divided into two height groups of up to 14.2 hands high (hh) and more than 14.2 hh, and weighed on a weighbridge; each horse then had its weight estimated by three weigh tapes, one height specific (tape 1 or 2, depending on the animals height) and two for general use (tapes 3 and 4). For horses up to 14.2 hh, weigh tape 1 provided the most accurate estimate of mean (sd) bodyweight (100.5 [6.2] per cent), and weigh tapes 3 and 4 were 112 (6.8) and 97.0 (6.1) per cent accurate, respectively. For horses more than 14.2 hh, weigh tape 2 provided the most accurate estimate of bodyweight (98.6 [18.4] per cent), with weigh tapes 3 and 4 being 102.6 (17.4) and 90.8 (15.2) per cent accurate, respectively.

Factors affecting owners’ choice of nutritional supplements for use in dressage and eventing horses

The aim of this study was to investigate the factors affecting horse owners’ choice of nutritional supplements for dressage and eventing horses. An online questionnaire was distributed to owners/riders of dressage and/or event horses to collect data on the demographics of the owner/rider and their horses, the sources of information used when choosing nutritional supplements and their opinion on these different sources. Data analysis included descriptive analysis and categorisation of free text. χ2 tests were used to explore factors affecting decision-making. In total, 757 responses were analysed. Participants obtained information on nutritional supplements from vets (49.8 per cent), internet article/review (39.4 per cent), other horse owners (38.7 per cent), coach/trainer (36.5 per cent) and nutritionists (33.4 per cent). They ranked the most reliable sources of information as vets, followed by nutritionists, then research studies, and the most influential sources of information as vets, followed by coach/trainer and nutritionists. Most participants had used other horse owners as their source of information for their most recent supplement. The age of the owner, competitive discipline, their educational qualification and their riding experience were significantly associated with aspects of decision-making. The study also identified a need for independent, unbiased sources of information on nutrition and supplements in the horse.

Contracting for care – the construction of the farrier role in supporting horse owners to prevent laminitis

BACKGROUND Emerging research highlights how, due to demographic changes in horse owner populations in Western societies, complex owner-horse relationships are leading to inappropriate horse care, including overnutrition, which in turn can lead to laminitis. Farriers, due to their regular visits, may be in a position to support owners in dealing with this problem. OBJECTIVES This study explored whether UK farriers have a role in working with horse owners to support horse welfare and prevent laminitis. STUDY DESIGN Grounded theory analysis, a qualitative methodology. METHODS Semi-structured interviews were conducted with 12 farriers and 11 horse owners. The interviews were transcribed verbatim and systematically analysed, using an inductive coding approach. RESULTS The analysis of the farrier and horse owner interview data revealed farriers and horse owners undertake a contracting process leading to either a task-focussed or holistic care-focussed approach. Either approach can be satisfactory, but the evidence from this study suggests that when horses are at risk of laminitis, a task-focussed approach misses important opportunities to prevent it. MAIN LIMITATIONS This analysis, based on a small sample of participants, was not able to identify the frequency of farriers or horse owners orientating towards different approaches in a way that can be generalised to a wider population. However, the power of grounded theory lies in its inductive design to develop new theory, which can be subsequently tested. CONCLUSIONS Farriers are in a perfect position to support horse owners to prevent laminitis through providing feedback, guidance and advice. However, not all farriers adopt this role and it is not necessary in all contexts. The evidence presented in this study has implications for equine veterinarians and welfare officers in educating horse owners about the value of holistic care-focussed farriery.