Between and hits were collected for both sheep and goats in each sample flock. This includes the relationships between digestibility end feed quality, and between seasonal conditions rainfall and the nutritive value of feed consumed measured in terms of energy or crude protein content. This guideline should be used in conjunction with other nutrient guidelines and dietary goals, in particular those related to fats and fatty acids including saturated fatty acids and trans-fatty acids , to guide development of effective public health nutrition policies and programmes to promote a healthy diet. Seasonal milk production using natural veldt Journal of Agricultural Science 56 1: Schools should discourage extended periods i.
For instance, a high proportion of fortes in the diet can usually be taken as an indication that minerals, in particular phosphorus, may not be deficient. The nature of nutritional constraints If solutions are to be identified, the nature of nutritional problems must be clearly defined. Studying the relationships between nutrition on the one hand and performance, management and grazing conditions on the other hand, as well as other nutritional relationships, might be useful in this context.
Relationships between nutrition and animal performance. By using techniques such as linear regression analysis, the relative importance of the different factors affecting production performance can be compared simultaneously.
Table 2 shows how performance could be related to different variables of which nutrition is only one. Relationships determining the effects of animal nutrition on production performance.
Dependent variable production performance Independent influencing variables 1. Fertility rate Seasonal conditions, breed, parity, disease, type of birth, sex of progeny 3. Milk production DM intake, 10 breed, parity, weaning period, disease, lactation length 10 When making comparisons between animals of different size to determine the importance of nutrition as a constraint, DM intake should be expressed in relation to the liveweight and preferably the metabolic weight, i.
When comparing animals of different species, the preferred exponent is LW 0. Various indicators or measures e. Surrogate or substitute variables for feed availability or intake can be used, as well.
For instance, seasonal rainfall is often assumed to be an indicator of feed conditions while stocking rate has been used as a substitute for feed intake Abel et al, Relationships between nutrition and management. The link between management practices and animal nutrition is often pronounced and needs to be understood. Examples of the relationships which might be studied are: Dahl and Sandford, ; Sandford, Crop residues can, for instance, have an important bearing on animal nutrition Bayer and Otchere, , by providing energy to carry stock through the dry season when feed quantity and nutritive value from grazing are low.
The availability of energy from stover will, therefore, influence mortalities and birth rates Powell and Waters-Bayer, ; Reed and Goe, Figure 2 gives a schematic representation of some of the linkages which commonly affect both crop and livestock performance.
Diagrams of this kind are useful in that they force the researcher to think through the system and identify some of the important linkages which exist. From this information, it is often possible to identify the data needs of research more precisely. Example of negative linkages between crop and livestock production in a mixed farming system. Relationships between nutrition and grazing conditions. These include the relationships between: Bayer and Otchere also suggest that grazing time affects calving and weaning percentages for cattle owned by pastoralists in the Nigerian subhumid zone.
This includes the relationships between digestibility end feed quality, and between seasonal conditions rainfall and the nutritive value of feed consumed measured in terms of energy or crude protein content. Such relationships need to be adequately understood if problems are to be correctly identified. For instance, a positive correlation between digestible energy or dry-matter intake and liveweight gain is commonly observed Ademosun et al, ; Zemmelink et al, Figure 3.
While this correlation may correctly imply that energy is a limiting factor in the diet, the availability of energy may itself be limited by some other factor e. Effective diagnosis thus depends on the identification of the primary limiting nutrient Little, Relationship between intake and liveweight gain in cattle, Mali, Lambourne et al Scope for improvement The scope for alleviating nutritional problems will depend very much on the characteristics of the system being studied.
In pastoral systems, where the range vegetation is the major source of feed, improvements in animal nutrition may be virtually impossible without first addressing issues related to land tenure communal grazing 11 and management e. While in mixed cropping systems, technologies which increase the quantity and nutritive value of stover fed to animals at the end of the cropping season might be applicable Powell It should be remembered that in livestock systems research, the solution to a particular problem may not always be technological.
For instance, it may be more important to correct particular aspects of policy before significant improvements in production can be achieved. Feasible technological solutions to improve animal nutrition may come through one or more of the following pathways: In mixed systems of production, livestock nutrition may be enhanced by improving the quantity and nutritive value of crop residues used by stock through: This involves changing livestock management strategies to match feed availability with livestock feed requirements.
For instance, Wagenaar et al and Wilson and Sayers have shown that change in the timing of births to match feed demands with feed supplies can have significant effects on conception rates and parturition number in sheep and goats. These involve ranching schemes which aim to improve the management of the range and raise productivity, principally through increasing in the amount of available forage. The available evidence suggests, however, that such schemes have mostly been unsuccessful in Africa Danckwerts, ; Behnke, The redistribution of water points to better utilise grazing resources is another example of a pasture improvement strategy.
Fodder banks are concentrated stands of forage, often legumes, sown either on natural grass or fallows to provide dry-season supplementary grazing Bayer, ; Mohamed-Saleem, ; Taylor-Powell and Ingawa, However, widespread adoption of forage legumes is constrained by competition for land with food crops, labour shortages during crop operations and lack of adapted species Reed and Goe, Among fodder trees, leucaena and sesbania have been shown to be suitable for animal feed supplementation by the ILCA alley farming programme in Nigeria Atta-Krah, Browse gardens and multipurpose trees have also been tried Reed and Soller, Types of data Animal data Feed data.
The objectives of data collection in this case are to Table 3: With some of these data e. It is recommended that, when such dab are required, the ARC standards should be used. Types of animal data used to diagnose animal nutrition problems. Objective Types of data Production effects Liveweight gain, condition scores, traction power, milk production, wool production Amount of feed consumed Feed intake Composition of feed consumed Oesophageal or rumen fistula samples, faecal samples, grazing behaviour studies selection data Feed data The principle objective, in this case, is to determine the nutritive value of the feed consumed and digested by the animal.
This may also involve an assessment of sources of feed as yet unutilised but with the potential for introduction into the diet.
In particular, data will be collected on digestibility, the energy value of feed dry matter, dry organic matter, digestible energy and metabolisable energy , and crude protein content When assessing the nutritive value of feed, differentiation on the basis of season or system of production which affect feed sources and feed availability will often tee useful.
Under certain circumstances see Part D below , data on the mineral content and fibre composition of a diet may be necessary.
When determining mineral content, samples of the feed consumed and of blood or bone may be needed. Methods of data collection Effects of nutrition on animal production performance Composition of consumed feed Feed digestibility Nutritive value of feed.
The discussion in Module 11 of different methods of data collection is generally applicable to all types of diagnostic research, and the user is encouraged to read it before embarking on studies of animal nutrition. The emphasis here is on those methods which have been tested by ILCA staff. Following the format adopted in Part C of this module, these methods have been grouped into methods used to measure: Effects of nutrition on animal production performance The production performance of an animal often reflects its nutritional status.
Liveweight and body condition, for instance, provide a measure of the nutritional response, integrated over weeks or months Lambourne et al, Studies which attempt to isolate the key factors influencing animal production performance may, therefore, be the first step in the diagnosis of animal nutrition problems see Part B above.
If nutrition is identified as the critical constraint to performance, further studies on specific aspects of nutrition related to the animal or the feed may be needed. The various methods used to assess animal production performance are discussed in Module 5, and the reader should refer to it if detailed diagnosis of production performance is envisaged.
For instance, there may be data available from range evaluation and animal production studies and farm management surveys, which specifically identify nutrition as the critical constraint to production.
Feed intake Intake, or the amount of feed an animal consumes, can be estimated by using either digestibility data or 'markers'. When such data are available, intake can be estimated by multiplying the dry-matter weight of faeces by a digestibility factor. The factor is known as the feed: Digestibility and intake data can be derived from the indigestible components of a diet, known as 'markers'.
Markers are classified as internal, if they are ordinarily present in the diet e. Synthetic organic substances such as beads, rubber and ribbon have also been used, since they can be easily separated from the feed. Van Soest provides a detailed account of the various markers used to estimate intake and digestibility, and of their advantages and disadvantages.
The term 'indicator' is sometimes used instead of 'marker' Dicko-Touré, , Church and Pond, ; Lambourne et al, The formula to estimate faecal output is: An animal is dosed with 50 g of chromic oxide per day to determine its daily faecal output.
The concentration proportion of marker in the dry-faeces sample is 5. The dry-matter weight of faeces excreted per day is g and 5. The proportion of the marker in the diet is 3. Calculate the DM intake of the animal. These can then be related to such variables as seasonal rainfall, stocking rate, management practices or plant composition to isolate its main determinants.
Summary The normal procedures to estimate DM digestibility and intake are to: This requires the further estimation of faecal output either by total faecal collection or dosing with known quantities of, for instance, chromic oxide. When facilities for laboratory analysis are not available or are inadequate, intake should be calculated on the basis of digestibility.
Simple methods to estimate digestibility are given in the text which follows. Composition of consumed feed There are various methods used to determine what the animal is eating.
Those discussed here are: The botanical composition of feed consumed by an animal can be determined by using a surgical fistula inserted into an animal's oesophagus.
The food eaten passes into a collection bag attached to the neck, and samples are taken directly from the bag after allowing the animals to graze for not more than two hours before re-inserting the fistula plug.
The oesophageal fistula method provides an accurate indication of the botanical composition of the feed consumed. An illustration of this type of approach is given by McLean et al However, because of salivary contamination of the samples, accurate direct estimates of the chemical composition of feed eaten are restricted to nitrogen, neutral detergent solubles, calcium, magnesium, sulphur and copper Little, ; Dietary phosphorus concentrations can be estimated accurately only from oesophageal extrusa labelled with radioactive P Little et al, It also tends to be time-consuming and costly, and farmers are unlikely to cooperate when their own stock is involved.
Nevertheless, ILCA research workers have used the method in the field. In Kenya, for instance, oesophageal fistulae were fitted to cows which had been purchased from Maasai pastoralists and herded with farmers herds during three seasons in several locations Semenye, a, b.
The data obtained on feed composition were then complemented by studies on grazing behaviour of the type discussed below. Material collected with the fistula method can be used in the determination of digestibility by in vitro estimation procedures see page This method is applicable to both cattle and smallstock and allows direct sampling of the contents of the rumen by means of a cannula surgically inserted into the rumen. It involves physically emptying the contents of the rumen by hand before the animal goes to graze and then taking samples from the freshly ingested material two to three hours after the animal started grazing.
It is therefore more likely to be applicable to on-farmlon-range experiments described in Section 2. Direct observation of grazing habits. The content of food consumed by grazing animals can be guesstimated by following selected animals in a herd or flock at distances which are close enough to observe what is being eaten. Each selected animal is observed at regular intervals.
Two field examples demonstrate the principles. De Leeuw and Chara used the technique to compare goat and sheep browse preferences in mixed Maasai flocks in Kenya. Observations were carried out during the dry season with randomly selected animals being followed for periods of one to two hours by one or two observers who were familiar with the local flora. Because the animals were familiar with humans, observations could be made at distances of m.
The aim was to obtain an equal number of 'hits' for sheep and goat - a 'hit' occurring each time a particular plant species was eaten. Hits per plant species were then summed and compared with the total number to determine the proportion of each plant eaten.
These figures were then used to derive an index of preference or selection. Between and hits were collected for both sheep and goats in each sample flock.
Nyerges observed the grazing habits of sheep, by following each for a period of 20 minutes measured by stop watch. Animals were followed at distances of m and the shrub and ground species consumed including ground litter during the observation period were recorded. Direct observation can also be applied to other studies of animal grazing behaviour, e. These variables can then be related to such parameters as intake, digestibility, stocking rate and distance to water, to isolate the more important determinants of grazing behaviour Lambourne et al, , pp.
A modification of the direct-observation method was used by Dicko-Touré in Mali to determine the composition of feed consumed. Selected animals were followed for a period of one minute, and distance walked as well as the number of mouthful taken during this period were recorded. A sample of forage was then collected by hand from the area grazed during the one-minute observation period.
The size of the sample taken was in proportion to the observed number of mouthfuls one hand-grab for every five mouthful. Similar measurements were made for each selected animal every 45 minutes throughout the day in order to obtain comprehensive data on feeding habits and feed composition.
Lambourne et al argued that, for most purposes, such rapid-survey techniques provide sufficient detail on diet composition. They are low-cost, require minimal supervision and can be completed in a relatively short time.
Observers should, preferably, have a good knowledge of local flora, but it is more important for them to be observant. If hand samples are collected to mimic grazing habits, these can be analysed at a later stage by someone who is thoroughly familiar with the flora. Data on diet composition can be complemented by opinions obtained from herdsmen in the area. Their knowledge about species differences in terms of selectivity and palatability is often very precise.
Pasture analysis before and after grazing. The 'before' and 'after' method involves the demarcation of quadrats in a paddock before and after animals are released into an area for grazing Figure 4.
Adjacent to each fenced quadrat is an equally sized area, with similar vegetation characteristics. The biomass and vegetation composition of the two 'paired' areas are measured using one of the techniques described in Module 6 and animals are then released into the area to graze t'Mannetje, Schematic representation of the pasture analysis method.
After a prescribed period e. The method will give reasonable estimates provided that the two areas are not highly variable in terms of species composition.
When vegetation is highly variable, the number of paired samples required must be increased, making measurement more time-consuming. Faecal samples have been used for microscopic analysis of the plant part they contain, to provide an indication of the vegetation consumed by an animal Stewart, However, as an indicator of dietary composition such samples tend to be unreliable since the indigestible portion of the diet may bear little relationship to the portion actually consumed.
The faeces may, for instance, contain high proportions of woody ligneous material consumed during browsing. This does not necessarily mean that the diet also contains similar proportions of this component.
Feed digestibility The methods used to assess digestibility are based on: Of these, only the first three are relevant to the diagnostic phase of livestock systems research.
The in vivo method is more applicable to on-station research and involves intensive laboratory work and careful supervision. The use of markers. When it is impossible or inconvenient to measure total feed intake or to collect total faeces, markers can be used to determine intake see pages as well as digestibility. The formula used to calculate apparent digestibility 16 is: Calculate the apparent digestibility of the feed.
To obtain data for the analysis based on markers, follow this procedure: There are two obvious sources of error in such a methodology.
First, lignin may be partly digestible and is thus not always a reliable indicator marker. Second, the feed samples taken will often be not truly representative of actual intake, particularly when pasture is highly variable, and where the choice of samples is entirely dependent on the enumerator judgement.
There are various methods available to sample faecal output in the field, including: This method is practical in a range context. Schneider and Flatt, However, Dicko-Touré, , p. She argued that the costs of using indicators to estimate faecal output would, in fact, have been more expensive since this method would have involved sending samples to another country at a cost that is at least 10 times higher than the cost actually incurred by using the bag-collection method.
Thus, the methods adopted in any diagnostic study to sample faecal output should be tailored to the particular circumstances of the study, bearing in mind the financial and manpower resources of the research team. The use of faecal indices. The methods using faecal indices to estimate digestibility are based on established regression relationships between faecal indices and the digestibility of dry or organic matter Van Soest, The general model for these relationships is: The two variables merely happen to go together i.
The estimation of digestibility via faecal indices involves the following steps: The main advantages of this method are that it is relatively low-cost and results can be obtained fairly quickly.
Its chief disadvantage is that it is site-specific, and the derived parameters and relations In vitro analysis of consumed feed. When digestibility is analysed by in vitro methods, samples of feed ingested are subjected to artificial tests which simulate digestibility under controlled conditions.
Examples of daily sources of calcium: Examples of daily sources of iron: Examples of daily sources of folate: Examples of daily sources of Vitamin C: For self-study and further research, check out these resources: May 10, at Radius 1 mile 5 miles 10 miles 15 miles 20 miles 30 miles 50 miles miles.
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It's been linked to an increased risk of many diseases, including obesity, heart disease, type 2 diabetes and cancer 1 , 2 , 3 , 4 , 5. Many people are now trying to minimize their sugar intake , but it's easy to underestimate how much you're actually consuming.
One of the reasons is that many foods contain hidden sugars, including some foods that you wouldn't even consider to be sweet. In fact, even products marketed as "light" or "low-fat" often contain more sugar than the regular versions 6. The American Heart Association recommends that women limit their added sugar intake to 6 teaspoons per day, while men should limit their intake to 9 teaspoons 7. A teaspoon of sugar contains 4 grams, so this amounts to 24 grams per day for women and 36 grams for men.
Most people today eat much more than that. Yogurt can be a highly nutritious food. However, not all yogurt is created equal. Like many other low-fat products , low-fat yogurts have sugar added to them to enhance flavor.
For example, a single cup grams of low-fat yogurt can contain up to 47 grams of sugar, which is 12 teaspoons. This is more than the daily limit for men and women in just a single cup of so-called "healthy" yogurt 8. Furthermore, low-fat yogurt doesn't seem to have the same health benefits as full-fat yogurt 9 , 10 , 11 , It's best to choose full-fat, natural or Greek yogurt.
Avoid yogurt that has been sweetened with sugar. However, 2 tablespoons of it can contain around 14 grams of sugar, or over 3 teaspoons If you are liberal with your servings, this makes it easy to consume a lot of sugar without meaning to. To make sure you aren't getting too much, check the labels and choose the sauce with the least amount of added sugar. And remember to watch your portions. Ketchup is one of the most popular condiments worldwide, but like BBQ sauce, it is often loaded with sugar.
Try to be mindful of your portion size when using ketchup and remember that a single tablespoon of ketchup contains 1 teaspoon of sugar Like whole fruit , fruit juice contains some vitamins and minerals. However, despite seeming like a healthy choice, these vitamins and minerals come with a large dose of sugar and very little fiber. It usually takes a lot of fruit to produce a single glass of fruit juice, so you get much more sugar in a glass of juice than you would get by eating whole fruit.
This makes it easy to consume a large amount of sugar quickly. In fact, there can be just as much sugar in fruit juice as there is in a sugary drink like Coke. The poor health outcomes that have been convincingly linked to sugary soda may be linked to fruit juices too 15 , 16 , Added sugars are often hidden in foods that we don't even consider to be sweet, such as spaghetti sauce.
All spaghetti sauces will contain some natural sugar given that they're made with tomatoes. The best way to ensure you aren't getting any unwanted sugar in your pasta sauce is to make your own. However, if you need to buy pre-made spaghetti sauce, check the label and pick one that either doesn't have sugar on the ingredients list or where it's listed very close to the bottom.
This indicates that it's not a major ingredient. However, sports drinks are designed to hydrate and fuel trained athletes during prolonged, intense periods of exercise. For this reason, they contain high amounts of added sugars that can be quickly absorbed and used for energy. In fact, a standard oz ml bottle of a sports drink will contain 32 grams of added sugar and calories, which is equivalent to 8 teaspoons of sugar Sports drinks are therefore categorized as "sugary drinks. Unless you're a marathon runner or an elite athlete, then you should probably just stick to water while exercising.
This is by far the best choice for most of us Chocolate milk is milk that has been flavored with cocoa and sweetened with sugar.