The acceptability and digestibility of mixtures containing selected fats of animal, vegetable and blended sources were studied. Ten fat containing mixtures were fed to Saddlebred horses in cafeteria style palatability trials and ranked according to preference. Preference ranking of the fats from highest to lowest is as follows: corn oil, blend no. 1, cottonseed oil, inedible tallow and fancy bleached tallow. When the most preferred fats from each classification (animal, vegetable and blended) were offered in single mixture palatability trails, no significant difference was observed in consumption. In Digestion Experiment I three fats, corn oil, blend no. 3 and inedible tallow, were added to an alfalfa and grain diet at the 102 level. The apparent digestibility of fatty acids in corn oil when calculated by difference, was higher than an inedible tallow or blend no. 3. The apparent digestibility of energy in corn oil calculated by difference, was 95.4%. However, this value was not different from that of inedible tallow and blend no. 3. The addition and kind of fat did not affect the apparent digestibility of acid detergent fiber or apparent absorption of minerals. Blood serum levels of total fatty acids, calcium, inorganic phosphorus, magnesium and glucose were not affected by the addition of the fats. However, serum cholesterol levels were increased (P <.05) by addition of fat. In Digestion Experiment II, feeding four fats (corn oil, peanut oil, inedible tallow and blend no. 3) at two levels (7.5 and 152%) was studied. When the apparent digestibility of fatty acids in the diet was calculated by difference, the average values were higher for corn oil and peanut oil, but the differences were not significant. The true digestibility of fatty acids showed all fat sources and levels were digested similarly. The apparent digestibility of diet energy was increased by the addition of the fats. The energy of diets containing corn oil had higher (P <.05) digestibilities than those containing inedible tallow or blend no. 3. As in Experiment I, there was no difference in energy digestibility of the added fats when calculated by difference. There was no depression of calcium absorption due to kind or level of added fat. Apparent absorption of phosphorus was not affected by type of level of added fat. Apparent absorption of magnesium was higher (P <.05) for the basal diet and those diets containing blend no. 3. Blood serum levels of total fatty acids, calcium, inorganic phosphorus, magnesium, cholesterol and glucose were not affected by the addition or type of fat. / Ph. D.

Call number: LD2668 .T4 1979 M25 / Master of Science

Two groups of three horses each were fed either a control diet of ground hay and concentrates or a similar diet with 10.5% added fat. The horses were trotted at 2.9 m/sec to a heart rate (HR) of 160 beats per minute (BPM) 5 d/wk on an equine treadmill set at go for a training period of 12 wk. A standard exercise test (SET) was performed at wk 0, 6, and 12. Blood samples were taken before, during, and after exercise and analyzed for lactate, glucose, cholesterol, total serum protein, and free fatty acids (FFA). Muscle biopsies were taken before and after exercise during the SETs on wk 1 and wk 12. Differences between wk 0, 6, and 12 in blood levels were found: lactate (P < .01) and glucose (P < .001) decreased, while cholesterol (P < .01) and FFA (P < .05) for both groups, indicating a conditioning response. However, no differences were found in any of the blood factors between groups. In the final SET, pre-exercise muscle glycogen levels in the fat-fed horses were lower (13.61 vs 25.44 mg/g wet tissue). Post-exercise glycogen levels, however, were higher in the fat- fed horses (10.95 vs 8.27 mg/g wet tissue), indicating that there may have been a glycogen-sparing effect. The fat-fed horses avg .3 kg/d less in daily consumption, and avg .03 kg/d more in ADG (.36 kg/d for control vs .33 kg/d for fatfed). Differences in trotting times (time to HR 160 BPM) between groups were seen at the end of four (P < .05) and eight (P < .05) Wki control horses improved 39% while fatfed horses only 25% from wk 1 to wk 8. No differences were seen between groups from wk 9 to 12. Improvement over the 12 wk period was similar for both groups (control 61%, fatfed 67%). These results seem to suggest that although fat appears to be a reasonable source of energy for the horse, there may be a long adaptation period for horses fed higher levels of fat. / Master of Science

Three yearling and three 2-year-old Saddlebred horses were used to determine seasonal differences in apparent digestibility of Ky 31 tall fescue (Festuca arundinacea Schreb.) pasture by horses. Three trials were conducted with collection periods beginning August 27, 1984; January 8, 1985; and June 3, 1985. Each 72 h collection period followed a 2 wk preliminary grazing period. The horses were given a pulse-dose of Yb impregnated fescue forage at 0 h, and fecal grab samples were taken at 6, 12, 18, 24, 30, 36, 48, 60, and 72 h after dosing. Fecal output was estimated from Yb concentration in the feces. Apparent digestibilities of dry matter (DM), acid detergent fiber (ADF), neutral detergent fiber (NDF), crude protein (CP), and cellulose were estimated using indigestible NDF as an internal marker. Forage DM intake was calculated using the formula (fecal output/(100- % forage DM digestibility) x 100). Estimated DM intake and fecal DM were 4.5 and 1.7 kg/d for August; 7.5 and 2.7 kg/d for January; and 6.4 and 2.8 kg/d for June, respectively. Percent ADF and NDF were highest (P<.05) and apparent digestibilities of these components were lowest (P<.05) for the spring forage. / Master of Science

An experiment was conducted to determine intake and apparent digestibilities of Kentucky 31 tall fescue (<i>Festuca arundinacea</i> schreb.) and orchardgrass/clover (<i>Dactylus glomerata</i> L./<i>Trifolium pratense</i> L.) pastures in different seasons of the year. Three digestion trials were conducted in December, 1985 (winter), May, 1986 (spring) and August, 1986 (summer). Five horses grazed each pasture type. A double marker procedure was used with indigestible neutral detergent fiber (INDF) and Yb as internal and external markers, respectively. Apparent digestibility of dry matter (DM), crude protein (CP), acid detergent fiber (ADF) and neutral detergent fiber (NDF) were determined. Digestibility of orchardgrass/clover components were not different between winter and spring, but were higher (P<.05) in DM, ADF and NDF digestibilities in the summer. Fescue DM and ADF digestibilities were higher (P<.05) in the winter while apparent digestibility of CP was higher (P<.05) in the spring. In summer orchardgrass/clover DM, ADF and NDF digestibilities were higher (P<.05) than fescue. Dry matter intake was not significantly different between forages. Orchardgrass/clover intake was lowest (P<.05) in the winter. Fescue dry matter intake was highest (P<.05) in the summer. / Master of Science

Lecithins may improve the digestibility of high fat diets and the tractability of horses. Experiments were conducted to determine the acceptability, digestibility and effects on behavior of lecithin-containing diets. Seven young horses of light breeds were used for the studies. The four concentrates consisted of corn, oats, beet pulp, trace mineralized salt, dried sugar cane molasses plus 10% added fat: corn oil (CO);soy lecithin-corn oil (SL\CO); soy lecithin-soybean oil (SL\SO); or soy lecithin-corn oil-soybean oil (SL\CO\SO). Half the ration was provided by chopped hay. The CO concentrate was the most palatable (P=.OOOl). The remaining three concentrates were palatable in the following order: SL\CO, SL\CO\SO, and SL\SO, with SL\CO diet preferred (P=.OOl) to SL\SO. In the digestibility experiment, a complete mixed diet was fed containing chromic oxide as a marker. The control diet had no added fat: the others contained CO, SL\CO, or SL\SO at 10% by weight. Apparent digestibility was higher in the control diet than in the others for dry matter (P=.OOOl). Apparent digestibilities of crude protein (P=.0002) and acid detergent fiber (P=.08) decreased with any of the three fats. In contrast, apparent digestibility of ether extract was increased (P=.OOOl) in the fat containing diets. In the activity experiments, horses on the SL\CO diet were less spontaneously active (P=.0125) than horses on the control diet. Horses on the CO and SL \SO diet also had slightly lower activity levels (P=.125). Horses fed the SL\SO diet reacted less (P=.0625) than control horses to the opening umbrella. Horses fed CO and SL\CO diets showed trends towards less reactivity (P=.125 and P=.25, respectively), compared to the control horses. These studies support the practical feasibility of using lecithins in diets for horses. Especially interesting would be studies of interactivity with trainers and riders. / Master of Science

Two experiments were conducted to investigate the effect of conditioning on the ability of the equine to digest and utilize nutrients and to determine the effect of dietary fat as an energy source on the physiological parameters associated with fitness using a standard exercise test. Conditioning horses increased apparent digestibilities of crude protein (CP) (P<.05), dry matter(DM), and acid detergent fiber (ADF) (P<.1). Conditioning also tended to increase the apparent digestibility of neutral detergent fiber (NDF), cellulose, cell contents, and energy. Heart rates and blood lactate levels indicated that the conditioned horses were fitter than their unconditioned controls. In the second experiment, horses were fed isocaloric diets, one containing added fat and the other a standard hay/corn diet. Adding fat while maintaining equal available energy concentration depressed apparent digestibility of dry matter (56.7 vs 67.3 % P<.05), cell contents (75.6 vs 82 %, P<.05), energy (61.2 vs 71.8 %, P<.05) and NDF (29.2 vs 51.3 %, P<.05), in unconditioned horses. There was a trend towards decreased apparent digestibility of CP and ADF. Addition of fat increased apparent digestibility of ether extract (89.2 vs 65.6 %, P<.05). Conditioning increased apparent digestibility of CP (64.8 vs 73.7 %, P<.05) and energy (61.2 vs 65.6 %, P<.05) and tended to increase apparent digestibility of DM (56.7 vs 60.8 % ) and ADF (26.8 vs 17.8 %) for horses fed a fat supplemented diet. Conditioning did not cause a change in apparent digestibility of ADF, CP, and DM in horses fed the control diet, or apparent digestibilities of NDF, ether extract, cell contents, or energy for either diet. There were no differences in physiological parameters used for assessing fitness (heart rate, blood lactate, and respiration rate), between horses fed a diet containing 14% added fat and no added fat. There was no difference in body temperature, blood glucose levels, blood urea-N (BUN), or creatine phosphokinase (CPK) between horses fed the two diets. / Ph. D.

Protein has been identified as a major reason that people purchase a horse feed, with anecdotal explanations offered for the poor prediction of response of horses to their rations, particularly in the sport horse market. The current research identifies through hierarchical cluster analysis that the myriad of riding feeds offered on the South African market fall into only four simple categories on the basis of wet chemistry. Feeds were subjected to the in vitro gas production technique (IVGPT) described by Pell and Schofield (1993), using equine faecal inoculum. Gas profiles, corrected for control fermentation profiles in the absence of substrate, were fitted to the model described by Campos et al. (2004) to derive GP kinetics. Gas production kinetics, and information in respect of pH, degradation efficiency, lag time and apparent and true digestibilities were obtained. The feeds were tested for glycaemic response in miniature horses using the hexokinase method with deproteinization using an auto analyser (Roche Diagnostics). Blood glucose parameters of feeds (mean, peak, slope and time to peak and area under the curve) in each group were compared by analysis of variance and regression with covariates. In vivo analysis of rates of passage and digestibility using using post-prandial percentages of acid insoluble marker collection was used to study the gastrointestinal process, to indicate foregut and hindgut compartmental flow. The need to balance nitrogen levels with a proportional supply of fermentable carbohydrate contradicts widely used protein intakes in the horse. In vitro fermentation was used in an analysis of nutrient synchrony, to identify optimal fermentative capacity for utilization of horse feeds. The characteristics of horse feeds were related to requirement and were composited in an analysis of the representation of horse feeds that would best reflect optimal utilization in the horse, to produce a method of feed characterisation that would lead to the optimal prediction of response of horses to feeds offered to South African horses. / Thesis (Ph.D.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

No description available.

This dissertation is the product of two behaviour studies and an in vitro fermentation trial. Both behaviour studies were conducted at the Ashburton Racehorse-Training Centre in Ashburton, near Pietermaritzburg in KwaZulu- Natal. The first behaviour study evaluated differences in behaviours obtained through feeding either twice or four times daily. This trial showed (P<O.OO1) that horses fed twice a day spend a greater proportion of their day in stereotypic or vice-like behaviours. Horses eating four times a day ate less hay (P<O.OO1) and more concentrate (P<O.05) than horses being fed twice a day. Horses in both yards ate more hay (P<O.05) when exercise intensity was increased. Defecation frequency was higher on days when exercise intensity was high (P<O.05) and in the yard where horses were fed four times per day (P<O.O1). Faecal weight was greater (P<O.05), horses lay down more frequently (P<O.05), spent more time eating concentrate (P<O.OO1) and less time eating hay (P<O.OO1) when horses were fed four times per day. Fillies spent more time (P<O.05) eating hay than geldings. The second behaviour study was conducted within one yard only and considered the effects of changes in management strategies on the incidence of stereotypic behaviour. The results did not indicate that changes in management related to exercise intensity would have an effect on behaviours exhibited. However this trial did demonstrate that a reduction in feed intake on days when exercise is reduced will reduce the incidence of stereotypic behaviours. Horses reduced the time spent eating hay when exercise was reduced except that when feeding frequency was reduced in conjunction with reduced exercise, more time was then spent eating hay (P<O.OO1). It was found that fillies spent more time licking surfaces (P<O.OO1) and weaving (P<O.O1) than geldings, which were more aggressive (P<O.OO1) and ate more bedding (P<O.05) than the fillies. All the horses were more alert (P<O.OO1) on days of moderate exercise except when feed was reduced in conjunction with reduced exercise, so that horses were less alert (P<O.OO1) and more time resting (P<O.OO1). The in vitro study was conducted at the department of Animal and Poultry Science at the University of KwaZulu-Natal, Pietermaritzburg. This was a dilution trial, using different ratios of maize and Eragrostis curvula. It was shown that as the proportion of maize in the ration was increased so the digestibility and the degradability of the ration increased (P<O.OO1). It was also shown that the adapted two stage digestion techniques described by Tilley & Terry (1963) had lower supernatant pH levels than the samples that underwent microbial digestion only. This was accounted for by a problem with the methodology. The trial had hoped to show a dramatic decrease in pH and increased rates of gas production when the maize portion of the sample was increased. From the results established during this trial it is clear that application exists in the adoption of this method in in vitro feed analysis in the horse industry.· The behaviour studies significantly linked the incidence of stereotypic behaviour to feeding and nutritional management in racehorses. Some explanations of the noted behaviours can be elucidated through the development of in vitro protocols, where hindgut pH, degradability and fermentation of different ration mixtures elicit responses in physical terms. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2007.