The role of nutritionists is to provide the scientific platform for the optimal performance and welfare of the horse. The feed and roughage are usually provided in a ratio that is suitable for the work rate of the horse and will be specified. The economy of the country plays a role in providing feed and competitiveness of the horses in those areas.
Nutrient synchronization has not yet been applied to the field of equine nutrition, but is critical in the optimal use of feed components in order to explain horse performance on different feeds. In Chapter 7, standard idle (80:20) and working (50:50) horse rations are compared in the forages' ability to contribute to the horse's daily nutrient requirements. As a hindgut fermenter, the capacity and demand of the foregut (x) and hindgut (y) determine a value for nutrients (z) that if overwritten (intake >z) means there are environmental consequences gastrointestinal tract of the horse.
To develop an integration of the information captured in the above research as an initial step towards developing a more rational approach to formulating horse feeds.
LITERATURE REVIEW
Markers
- External Markers
- Internal markers
Acid insoluble ash (AIA) has been the most frequently used marker in horse studies (Sutton et al., 1977; Cuddeford. The cost of use Colyer et al., 2003) as Markers can be used to describe feed digestibility at output in cases where total defecation is impossible, dry matter, 1999;. Stevens et al., 2002; Lindsay, ut, The faecal excretion pattern over time for determining the rate of passage and mean retention of digestion in et al., 2002; Lindsay, based on the difference between the dry matter intake of nutrient and marker and the dry matter retrieved in faeces (Bush et al., 2001):
AIA is considered superior to ADL in equine digestibility studies because the latter was not completely recovered in the feces (Miraglia et al., 1999). Furthermore, some of the lignin could be digested by microbial activity in the cecum (Goachet et al., 2009), but this is questionable. Lignin is a naturally occurring marker in equine feedstuffs (Miraglia et al., 1999) and is therefore still used.
This method has also been used in horses, where the horses were provided with an ileum or cecal cannula (Bush et al., 2001;.
In vivo Systems (Digestibility Experiments)
Digestibility is the product of the retention time and the degradation properties of a food (Forbes, 1996). The digestibility of the basal feed is known and it is assumed that the nutrients in this basal feed will have the same digestibility as they had when they made up the whole diet. One assumes that by mixing the two feeds, one will not change the digestibility of the other.
The level of inclusion of the test feed should be high enough to ensure that differences between the test and basal feed are observed. The smaller the ratio of the test food to the basic food, the greater the number of animals required for the test. A series of digestion tests can be performed at which different levels of the test food is added to the basal food.
ND= apparent digestibility of nutrients in the concentrate or the feed nutrient and TDN is the total apparent digestibility of the nutrient.
In vitro Systems
FRGP is the fractional gas production rate estimated when 50% of the gas has been produced GP is the total gas production. In vivo this is related to the time digestion spends in the intestine (Campbell et al., 2002). Lindsay (2005) modified this method to mimic the digestive system of a horse rather than a ruminant.
Gas production technique is a measure of the proportion of feed that is fermented (Rymer, 1999). In an experiment by Murray et al. 2003), the source of faecal inoculum collected from ponies fed diets with different levels of starch had little effect on the results of an in vitro digestibility study. However, allowing the gas pressure to increase can change the gas production profile (GP) (Theodorou et al., 1998; Rymer, 1999).
The feeding program of the inoculum donor animal is important in that the amount of gas produced is greater when rumen fluid is taken from steers fed grain instead of hay (Trei et al., 1970; Cone et al., 1996).
Near infrared spectrophotometry (NIRS) and GLC
Nutritional evaluation
Crude fiber contained some, but not all, of the polymers that make up the plant cell wall, while NFE included water-soluble carbohydrates, starch, organic acids, and a large portion of the pectin fraction of cell walls. These measures have now been replaced by the direct determination of water-soluble compounds and neutral detergent fiber (NDF). Chemical analysis is the starting point for determining the nutritional value of food, but the value of a food does not depend entirely on the amount of different nutrients it contains.
The value of a feed depends on the quantities of these nutrients that the animal can digest and use. The true standard must be the interaction between chemical composition and digestion, because the factorial of these two aspects will determine the quality of the feed to the horse. It is only the digestible part of the feed that can serve to maintain the vital functions and is of value for energy and the formation of animal products, and to ensure animal performance.
However, the chemical composition and the percentage of digestibility are not all that determine the value of a feed.
Flow of Nutrients
- Fat
- Protein
- Carbohydrate
No ergogenic potential can be identified in excess protein intake (Snow, 1994; Harris and Harris, 2005). A balanced dietary NDF/starch ratio and probiotic support (S. cerevisiae) can limit the extent of undesirable changes in the horse's intestinal ecosystem (Medina et al., 2002). Bacteria in the cecum break down urea to form protein, but protein absorption does not occur in this region (Schmitz et al., 1991).
A slowly fermented group (produces mainly acetate and butyrate, metabolized as 2C and 4C units by acetyl-coA (Hoffman, 2003); fractions 2 and 3 absorbed in the hindgut. High-energy diets can inhibit the digestion of structural CHO in affecting the hindgut (Julliand et al., 2004). Their digestion is dependent on the fermentation rate and the retention time in the cecum (Harbers et al., 1981).
An excessively high C:N ratio results in increased acid production (Ghasimi et al., 2009), a problem that could be extrapolated to the hindgut.
Feeding Management
Consumers will pay a premium price for high-quality products that directly acknowledge their view of the horse as both a livestock-equine partner and a companion (Kline, 2004). The horse's digestive system does not vary from breed to breed, and yet horse owners request it. It therefore becomes imperative that the nutritional needs of the horse in a management system contrary to its historic habitat are addressed.
Not every problem in the yard can be laid at the door of the nutritionist (Jackson, 2003). Consider the behavioral strategy of the horse in the historical context: the horse is a social being, with a hierarchy defined by its herd, and a time budget defined by its nomadic, non-territorial existence. Nutritional needs of the horse are the sum of the requirements for maintenance, work, growth, reproduction and lactation.
As early as 200 BC, Xenophon (200 BC) was an advocate of providing several oats per day for energy for the work horse.
Objective Functions
49 Work demands on intestinal capacity dictate that roughage is replaced by concentrates, and permutations of concentrate and roughage provision have been investigated to reduce the incidence of stereotyping (Hackland, 2007). Many nutrition-related problems will manifest as stereotypical behavior or physiological problems in stabled horses (Frape, 1994). The most common ailments and problems associated with feeding are due to boredom and confinement, irregular feeding times, restriction of social interaction between horses during feeding times, feeding highly concentrated rations that are consumed quickly, insufficient roughage and the lack of opportunities for self-movement. or regular exercise (Kohnke, 1998; Harris and Bishop, 2007).
There are a number of serious disorders associated with horses consuming high levels of grain and digestible carbohydrates (Kalck, 2009) and while the negative consequences of grain feeding are varied, a major cause is the development of acidic conditions in the hindgut. (Willard et al., 1977). Feed management objectives, including roughage: concentrate ratio (Kienzle et al., 2002) and forage stem length and feeding frequencies, can be reflected by transit rate, glycemic response and fermentation kinetics, as and performance parameters that have been defined for that class of horse (Gordon et al., 2007).
Nutritional Modelling in the Horse
Horse forage classification variables (crude protein, fat, neutral detergent fiber) and calculated non-fermentable content (100-CP-fat-NDF) were used to create four canonical variables. The maximum gas production is related to the A value (rapidly degradable fraction) of the feed. For horse feeds, this ensured the separation of alfalfa-based feeds from others.
The addition of concentrates to horse diets is reflected in the horse's blood glucose response. These overcome many limitations in the routine use of in vivo experiments (Broderick and Cochran, 2000). Fast transit times may explain the position of the fermentation center in the context of the GIT.
In vitro fermentation evaluates the consequences of the arrival of , CHO and lipids in the cecum and the production of fermentation products. The classification variables used in creating the clusters were included in the GLM procedure. Should the ratio of nutrients in a horse's historical program inform current feeding programs.
The capacity of feed to reside in the cecum, with the accompanying characterization of feeds in terms of their fermentative capacity (Chapter Three), means that compartmental flow parameters may well provide an explanation for the behavior of feed ingredients in sections of the GIT, which can then be correlated with behavioral manifestations in the horse (Ellis and Hill, 2005). Investigation of the use of exogenous α-amylase and amyloglucosidase to improve starch digestion in the small intestine of the horse.
