Insulinaemic and glycaemic responses to three forages in ponies.

Reduction of the hyperinsulinaemic response to feeding is central to the management of insulin dysregulation (ID). The aim of this study was to compare insulinaemic and glycaemic responses to soaked hay, dry hay and haylage in ponies. Twelve ponies of mixed breeds were maintained under identical management conditions. A randomised four-way crossover trial was conducted, in which fasted animals were fed a meal of 0.25% body weight as dry matter intake soaked hay, dry hay or haylage, or administered an oral glucose test (OGT). Blood glucose and serum insulin concentrations were measured before and at 2h following OGT, and regularly for 5h following forage meals. Median and interquartile range (IQR) area under the curve (AUC) for insulin (AUCi) was greater for haylage (median 6495; IQR 17352) vs. dry hay (2932; IQR 5937; P=0.019) and soaked hay (1066; IQR 1753; P=0.002), and greater for dry hay vs. soaked hay (P=0.002). The AUC for glucose (AUCg) was lower for soaked hay (1021; IQR 99) vs. dry hay (1075; IQR 105; P=0.002) and haylage (1107; IQR 221; P=0.003). Six ponies were classified as having ID based on the OGT. AUCi was greater in ID vs. non-ID ponies after all forages. In contrast, there was no detectable effect of ID status on AUCg. On an equivalent dry matter basis, soaked hay produced the lowest insulinaemic and glycaemic responses to feeding, while haylage produced the highest responses. The insulinaemic effects of all forages were greater in ponies with ID. These data support the practice of soaking hay with water to reduce postprandial insulinaemic responses in ponies.

Impact of feeding and housing systems on disease incidence in dairy calves.

Contentious issues in calf rearing include milk feeding level and single versus group housing. The current study was performed on a high-producing 170 Holstein cow dairy farm to investigate the impact of nutrition and housing on disease incidence. Calves (n=100) were allocated in birth order to one of two commonly used feeding strategies. Group A calves were group housed from birth and fed ad libitum milk replacer (MR) via a computerised machine using a single teat, with weaning commencing at 63 days. Group R calves were initially housed in individual pens receiving 2.5 litres of MR twice daily via a bucket until three weeks of age when they were group housed and fed 3 litres of MR twice daily via a group trough with weaning commencing at 56 days. In total, 80 (80 per cent) calves suffered from at least one incident of disease during the period from birth to 12 weeks. Group A calves had a greater risk of disease than group R calves (diarrhoea: OR 3.86 (95 per cent CI 1.67 to 8.9); pneumonia: OR 5.80 (95 per cent CI 2.33 to 14.44)). There was a 5.1 per cent incidence of failure of passive transfer of Ig assessed via measurement of plasma total protein concentrations at 48 hours of age. It is hypothesised that the increased diarrhoea risk in group A calves was most likely associated with group housing, while the increased pneumonia risk was associated with the use of a single teat allowing increased transmission of pathogens from calf to calf.

Dietary restriction in combination with a nutraceutical supplement for the management of equine metabolic syndrome in horses.

Few studies have examined the effect of dietary restriction in horses with equine metabolic syndrome (EMS). This study aimed to determine improvements in insulin sensitivity following dietary restriction for 6 weeks, and to determine if the improvement would be greater in horses receiving short-chain fructo-oligosaccharides (sc-FOS). Dietary management involved feeding grass hay, restricted to 1.25% of body mass (BM) as daily dry matter intake and soaked in cold water prior to feeding, with the addition of a vitamin and mineral nutraceutical supplement with or without the addition of sc-FOS (10 g/100 kg). Soaking the hay resulted in a significant reduction in non-structural carbohydrates (38%, P = 0.01), digestible energy (6.78%, P = 0.01) and water soluble minerals. Following 6 weeks of dietary restriction with soaked grass hay and nutraceutical supplement, horses lost an average of 6.8% BM and showed reductions in body condition score (BCS) and belly circumference. Sensitivity to insulin improved overall, as determined by the total insulin response during the combined glucose insulin test. The magnitude of improvement in insulin sensitivity was associated with the degree of insulin resistance recorded at outset, and the extent of overall losses in BM and BCS, but was independent of the addition of sc-FOS. The nutraceutical supplement was highly palatable and no adverse effects were noted. From the findings of this study a strict dietary program in combination with a specifically designed vitamin and mineral nutraceutical supplement can be recommended to obtain rapid improvements in BM, BCS and insulin sensitivity of animals presenting with EMS.

Effect of dietary restriction on body condition, composition and welfare of overweight and obese pony mares.

REASONS FOR PERFORMING STUDY: Increased prevalence of obesity among UK horses and ponies demands evidence-based advice to promote weight loss. HYPOTHESIS: Restriction of dry matter intake (DMI) to 1% of body mass (BM, 67% [corrected] of predicted maintenance digestible energy [DE] requirements) would promote weight loss without compromise to health. METHODS: Five mature (mean ± s.e. 10 ± 2 years), overweight/obese pony mares (BM, 257 ± 20 kg: body condition score [BCS] 6.8/9 ± 0.5) were studied over 12 weeks. Animals were individually housed. Daily provision of a chaff-based, complete diet (measured DE, 8.5 MJ/kg DM) was restricted to 1% of actual BM as DMI daily. BCS, girth measurements and ultrasound-derived measures of subcutaneous fat depth overlying the gluteal region and 12th intercostal space (rib-eye) were recorded weekly. Body fat content was estimated at the beginning and end of the study by deuterium oxide dilution methods. Clinical biochemistry was monitored weekly. Behaviour was observed (24 h, 3/5 ponies) on 3 occasions. RESULTS: BM decreased by 4.3 ± 1.1% during the first week and thereafter by 0.7 ± 0.1% of BM at end of Week 1 each week. BCS remained constant. Heart and belly girths, rump width and subcutaneous fat depth at rib-eye decreased significantly with time and BM. Fat comprised 45 ± 19% of BM loss. Fatter animals lost relatively more fat. With decreased feeding activity, time spent in 'play' and rest increased by 36 ± 11% and 438 ± 95%, respectively. CONCLUSIONS: This plane of nutrition resulted in an overall rate of weight loss of 1% of outset BM weekly. BCS was not a useful index of early weight loss but heart and belly girths and subcutaneous rib-eye fat were identified as alternative markers. POTENTIAL RELEVANCE: This study provides an evidence-base for the management of weight loss in obese animals, especially those for which exercise may be contra-indicated.