Horses are one of the few species, beside humans, in which assisted reproductive technology has important clinical applications. Furthermore, the horse can serve as a valuable model for the study of ...comparative reproductive biology. Here we present the first comprehensive characterisation of energy metabolism and mitochondrial efficiency in equine cumulus-oocyte complexes (COCs) during in vitro maturation (IVM), as determined using a combination of non-invasive consumption and release assays and mitochondrial function analysis. These data reveal notable species-specific differences in the rate and kinetics of glucose consumption and glycolysis throughout IVM. Approximately 95% of glucose consumed was accounted for by lactate production; however, high concurrent oxygen consumption indicated a comparatively increased role for non-glycolytic oxidative phosphorylation. Up to 38% of equine COC oxygen consumption could be attributed to non-mitochondrial activities and there was a significant loss of spare respiratory capacity over the course of IVM. Notably, our data also revealed that current IVM protocols may be failing to satisfy the metabolic demands of the equine COC. Our findings constitute the first report on mitochondrial efficiency in the equine COC and provide new insight into comparative gamete biology as well as metabolism of the COC during in vitro maturation.
Summary
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, 6% 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.
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.
•The insulinaemic and glycaemic responses of ponies to soaked hay, dry hay and haylage were compared.•Soaked hay produced the lowest insulinaemic and glycaemic responses to feeding, whilst haylage ...produced the highest responses.•Insulin-dysregulated ponies had a higher insulinaemic response to all forages than ponies without insulin dysregulation.•The insulinaemic response to feeding hay was reduced after soaking the hay.•Feeding haylage can result in a pronounced insulinaemic response.
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.
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 6weeks, 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 (10g/100kg).
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 6weeks 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.
Reasons for performing study
Soaked grass hays are recommended for the nutritional‐management of equine metabolic syndrome (EMS). Forage provision is commonly restricted to promote weight‐loss and ...insulin‐sensitivity. When EMS animals were fed hay at ∼1.25% body mass (BM) as daily dry matter (DM) (presoaking) animals lost weight at 1.1% of outset BM weekly. This doubled weight‐losses recorded when horses were fed fresh/‘un‐soaked’ hay to the same level 1.
Objectives
To compare the composition and digestibility of fresh/soaked grass‐hays to improve nutritional‐guidance for the management of EMS.
Study design
Following 6 weeks of dietary restriction to 1.25%BM as hay‐DM, 6/12 horses which had participated in an earlier study 2, were used to determine the digestibility of the soaked (n = 3) and fresh (n = 3) hays.
Methods
Samples of fresh grass‐hay (n = 6) and hay from the same batch which had been water‐soaked overnight (16 h, n = 6) or by day (7 h, n = 6) were dried for the measurement of DM content, pooled and ground. Nutrient and gross energy (GE) compositions were determined by proximate analyses. Animals were fed hay as 2 daily meals. Soaked‐hay was equal‐parts long/short‐soaked. Apparent digestibilities were determined after total faecal collection for 72 h.
Results
Soaking hay; did not alter GE (17.6 MJ/kg DM), increased acid detergent fibre (ADF) (30–35%), neutral detergent fibre (NDF) (68–74%) and crude protein (CP, 8.4–10.6%), decreased water soluble carbohydrate (WSC, 18.2–12.2%), and mineral contents (5.7–4.2%). Digestibilities of GE, DM, ash, NDF and WSC were unaltered by soaking. Conversely, soaking increased CP (55.6–66.8%) and ADF (37.5–50%) digestibility. However, hay‐soaking elicits un‐quantified losses of DM. Previous studies report hay ADF and CP as ‘water‐insoluble’. When DM losses were retrospectively calculated from the ADF and CP content of fresh and soaked‐hays, daily DM provision decreased from 1.25 to 1.14%. Consequently DE decreased by 25% (119.5–89.7 kj/kg BM/day).
Conclusions
Dry matter losses from hay‐soaking have marked impacts on energy/nutrient provision and increase the severity of dietary restriction.
Ethical animal research: The study was approved by the University of Liverpool, Veterinary Research Ethics Committee. Owners gave informed consent for their horses’ inclusion in the study. Sources of funding: Personal research account. Competing interests: None.
Two comparative studies were undertaken using adult, female red and Père David's deer to examine the ovulatory response of these animals to a superovulation regimen and fertilization rates following ...inter- and intraspecific laparoscopic insemination. In Expt 1 six Père David's deer and 12 red deer hinds were treated during the breeding season with an intravaginal progesterone-impregnated controlled internal drug release device (CIDR) for 14 days, with 200 iu pregnant mares' serum gonadotrophin (PMSG) administered 72 h before the device was withdrawn and eight injections of ovine FSH given at 12 h intervals starting at the time of PMSG administration. Oestrous behaviour began one day after CIDR device withdrawal (Père David's deer: 24.00 +/- 2.32 h; red deer: 24.60 +/- 2.23 h). The duration of oestrus was greater in Père David's deer than in red deer (17.50 +/- 1.43 h and 8.25 +/- 3.25 h, respectively, P < 0.001). The peak LH surge of Père David's deer was 68.65 +/- 4.74 ng ml-1 occurring 29.00 +/- 2.41 h after removal of the CIDR devices. In comparison, the peak LH surge in red deer was 17.09 +/- 3.64 ng ml-1 (P < 0.001), occurring 24.00 +/- 0.00 h after CIDR device withdrawal. Pre-surge concentrations of LH were also greater (P < 0.001) in Père David's deer (1.37 +/- 0.11 ng ml-1) than in red deer hinds (0.41 +/- 0.02 ng ml-1).
The horse, as a hindgut fermenter, is reliant on its intestinal bacterial population for efficient diet utilisation. However, sudden disturbance of this population can result in severe colic or ...laminitis, both of which may require euthanasia. This study therefore aimed to determine the temporal stability of the bacterial population of faecal samples from six ponies maintained on a formulated high fibre diet. Bacterial 16S rRNA terminal restriction fragment length polymorphism (TRFLP) analyses of 10 faecal samples collected from 6 ponies at regular intervals over 72 hour trial periods identified a significant pony-specific profile (P<0.001) with strong stability. Within each pony, a significantly different population was found after 11 weeks on the same diet (P<0.001) and with greater intra-individual similarity. Total short chain fatty acid (SCFA) concentration increased in all ponies, but other changes (such as bacterial population diversity measures, individual major SCFA concentration) were significant and dependent on the individual. This study is the first to report the extent of stability of microbes resident in the intestinal tract as represented with such depth and frequency of faecal sampling. In doing so, this provides a baseline from which future trials can be planned and the extent to which results may be interpreted.
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