Nutritional value of zero-tannin faba beans for grower-finisher hogs

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Zero-tannin faba beans are a potential replacement of soybean meal in swine diets. The chemical characteristics, energy and amino acid (AA) digestibility, the content of DE and NE, and tannin content of zero-tannin faba beans were determined and indicate, together with the subsequent growth performance variables and carcass quality of grower-finisher pigs, that zero-tannin faba beans can replace soybean meal and result in similar performance in grower-finisher pigs.

Enzyme Supplementation and Feed Processing Solutions Provide Solutions for Low-Quality Grains

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The nutritional quality of wheat or barley can vary substantially (see previous Centre of Swine Volume 10 Number 3). Ignoring the existing variation may cause lower finished feed quality and thereby impact the swine producer economically through reduced growth performance.

For wheat and barley, reduced nutritional quality usually means a reduced digestible energy (DE) content. The reduction in DE content is almost completely caused by a reduction in energy digestibility, not by a reduction in the total amount of energy in the ingredient sample (or gross energy = GE content). The reduction in energy digestibility is usually related to an increase in fibre content of the grain.

Solutions for the use of low quality grains in diet formulations while maintaining growth performance should focus on two aspects: (1) correcting diet formulations to achieve the formulated diet DE content or (2) enzyme supplementation or feed processing to overcome to reduction in energy digestibility of the grain. For either solution, correct prediction of DE content of individual wheat and barley samples may be critical, but the impact of correct prediction of DE content on further decision making regarding enzyme supplementation or feed processing to improve energy digestibility is poorly understood. Equations to predict DE content of wheat and barley are presently being evaluated using the 2002-harvest.

To study whether a specific wheat sample would impact the beneficial effects of enzyme supplementation or feed processing, three samples of wheat were collected from the 2002-harvest. The three wheat samples (W1, W2, and W3) had a similar content of crude protein (18.8 to 19.7% DM) but had a wide range in neutral detergent fibre (NDF) content (W1, 20.1; W2, 29.3; and W3, 35.7% DM).

Results of a digestibility study with grower pigs indicate that the increased fibre content for samples W1 to W3 indeed resulted in decreased energy digestibility (Figure 1) and reduced DE content from 3,680 to 3,320 kcal/kg DM, confirming the importance of ingredient evaluation and that an increase in fibre (NDF) coincides with a decrease in energy digestibility and DE content. The range in wheat DE content also reflects a range in economic value of more than $15 per tonne of wheat used for swine feed.

Wheat diets were supplemented with a carbohydrase enzyme (xylanase). The enzyme should help the pig to digest energy, because negative effects of fibre fractions (or arabinoxylans) on energy digestibility will be alleviated. Indeed, enzyme supplementation improved energy digestibility for wheat samples W2 and W3, but not for wheat sample W1 (Figure 2), indicating that the beneficial effect of enzymes is dependent on the wheat sample in the diet. This result further stresses the importance of ingredient evaluation, or the importance of enzyme supplementation to alleviated expected differences in energy digestibility. The underlying reason for the positive response for W2 and W3 to enzyme supplementation and the lack thereof for W1 will be related to the content of fibre fractions in the wheat, specifically the fraction called xylan. Therefore, the wheat samples are presently being analysed for these fractions to further related wheat characteristics to prediction of an enzyme response.

Wheat samples were ground across three hammer mill screens to achieve a predicted particle size of 900, 650, and 400 mm (microns). Particle size reduction should help the pig to digest energy, because a finer particle size means that the ratio of surface area to volume of the particles is increased. In other words, digestive enzymes of the pig or microbes of the pig have better access to the nutrients with a finer particle size. Indeed, enzyme supplementation improved energy digestibility for wheat samples W2 and W3, but not for wheat sample W1 (Figure 3), indicating that the beneficial effect of particle size reduction is dependent on the wheat sample in the diet.

Xylanase and phytase supplementation on growth performance of grower pigs

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The nutritional value of wheat millrun with xylanase and (or) phytase supplementation in wheat based diets for growing pigs was evaluated. Wheat millrun inclusion depressed energy and P digestibility and also ADG, but had no effect on ADFI and G: F. Xyalnase and phytase reduced ADFI and improved nutrient digestibility. However, the improved nutrient digestibility did not result in improved growth performance.

Variation in Feed Quality: What To Do When It Declines

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Introduction
Feed ingredients, such as barley and wheat, vary substantially in quality. If the variation in ingredient quality is ignored, the quality of finished feed may vary, resulting in changed feed intake and/or reduced growth performance. Feed ingredient quality is thus a nutritional and economic concern in the pork industry, especially the quality differences that are related to energy intake or protein deposition. Feed ingredient quality is related to its chemical composition and not to physical characteristics (bushel weight). Thus, ingredient chemical characteristics should be analyzed regularly. Analyses can be considered an investment to ensure a predictable growth performance.
Variation in ingredient quality has become increasingly important for the pork industry, because minimizing the differences between actual and calculated quality of finished feed helps to achieve a predictable performance. Diets are formulated using least-cost diet formulation, and safety margins have been included to guarantee minimum dietary nutrient levels. These margins could be reduced if ingredient quality is monitored properly. Analyses or predictions of nutrients with the greatest impact on diet cost or performance (energy, amino acids) is the most effective way to manage variation in ingredient quality, and will likely provide a high return on investment.

Variation in feed quality
Feed ingredient quality is now defined as digestible nutrient content rather than total nutrient content. Most swine nutritionists in western Canada use digestible energy (DE) and digestible amino acids to describe ingredient quality. The nutritional value of ingredients is a function of their digestible nutrient content and the pig’s voluntary feed intake (VFI).
For cereal grains, DE is the most valuable nutrient. Variations in the DE content of western Canadian wheat (range of 630 kcal/kg) and barley (range of 450 kcal/kg) can be large, due to changes in the grain’s energy digestibility. In the last decade, we have related changes in the DE content of wheat and barley to changes in their fibre or non-starch polysaccharide (NSP) content (Zijlstra et al. 1999; Fairbairn et al., 1999). Based on the relations, we have developed equations that predict the DE content for barley and wheat based on their chemical characteristics.

Prediction of wheat DE. Our best equation for the prediction of wheat DE content on a dry matter (DM) basis was based its fibre (neutral detergent fibre; NDF) and protein (CP) content:
DE (DM) = 3,584 + 38.3 x CP (DM) – 16.0 x NDF (DM) (R2 = 0.75)

Prediction of barley DE. Our best equation for the prediction of barley DE content on a DM basis was based on its fibre (acid detergent fibre; ADF) content:
DE (DM) = 3,918 – 92.8 x ADF (DM) (R2 = 0.85)

Use of prediction equations. Theoretically, prediction equations are only valid for the range of chemical characteristics used to create the equation. Some wheat samples from the 2002-harvest have a unique combination of chemical characteristics (CP and NDF) that have not been measured before. Thus, the existing equations to predict the DE content of wheat based on CP and NDF may not be valid for a large portion of the 2002-harvest. The 15 wheat samples used to create the original prediction equations (¨) have a lower CP and NDF contents than some samples from the 2002-harvest (à) (Figure 1). Thus, the existing prediction equations should be used cautiously. Barley and wheat samples from the 2002-harvest should be analysed for their chemical characteristics and DE content in grower pigs to validate and improve upon these prediction equations.

Origin of variation in DE. Barley and wheat available in western Canada vary substantially in their nutritional value. For example, the DE content of 20 barley samples ranged from 2,700 to 3,100 kcal/kg, a range that cannot be explained by the samples’ gross energy (GE) content (Figure 2). The range in wheat or barley DE content is therefore mostly due to a change in energy digestibility. A current hypothesis is that a reduction in DE content or energy digestibility is partly due to higher fibre levels. Consequently, low quality grain samples might therefore be more responsive to treatments that enhance energy digestibility.

Voluntary feed intake. Apart from ranges in DE content, a range of feed intake has been described for Australian wheat in weaned pigs (Cadogan et al. 2000) and western Canadian wheat in broiler chicks (Swift et al. 1998). A range of energy digestibility exists for western Canadian wheat (Zijlstra et al. 1999); however, the range in energy digestibility is not related to changes in feed intake in weaned pigs (Cadogan et al. 2000) or broiler chicks (Swift 1998). The existence of a range of feed intake and energy digestibility in western Canadian wheat fed to weaned pigs has not been confirmed to date. A recent study using 12 Canadian wheat varieties organized into 2 varieties in 6 wheat classes did not show a range in feed intake or growth performance for weaned pigs. However, the wheat samples included in this study did not differ much in fibre content and thus quality (Zijlstra et al. 2003).

Economic implications of ingredient quality
The economic implication of variation in feed ingredient quality was calculated for two scenarios.
Scenario 1. A change in quality will change the economic value of the ingredients. For wheat, the economic impact of a 5% change in the digestible lysine (dLYS) or DE content was calculated for grower pigs. Lysine-HCl (78% dLYS; $2.45/kg) and canola oil (8,800 kcal DE/kg; $0.89/kg) were considered as purified sources of dLYS and DE. Assuming that wheat has a mean nutritional value of 0.29% dLYS and 3,425 kcal DE/kg, a 5% difference in these nutrients will be 0.15 kg dLYS in a tonne of wheat and 171 kcal DE in a kg of wheat. The economic value of the 5% difference is per tonne of wheat is:

For dLYS: (0.15/780) * $2,450 = $0.47/tonne
For DE: (171/8,800) * $890 = $17.29/tonne

The higher economic value for the change in DE compared to digestible lysine verifies that the greatest cost-pressure with least-cost diet formulation is against dietary DE content (Zijlstra et al. 2001).

Scenario 2. If changes in energy content are ignored, pig performance may be affected. An unaccounted for reduction in dietary DE content and thus DE intake may reduce gain if feed intake is not increased, or may reduce feed efficiency if feed intake is increased to maintain the DE intake. The following estimates of costs were made for a 7% reduction in DE intake, using data from an energy intake study.

A reduction in gain of 70 grams per day results in pigs that are 8 kg lighter at slaughter after 16 weeks in the grower-finisher barn. The lower body weight at marketing would result in a loss of $10.56 per pig sold, assuming a market price of $1.50/kg and an average index of 110.

An increase in feed intake of 7%, to compensate for the reduced dietary DE content, may increase feed conversion by 0.2 kg feed per kg gain, which would increase feed costs by $2.95 per pig sold.

Change in diet formulation
Reaching a predictable performance is important to maximize net income. But to reach a predictable performance the actual diet DE content should be close to the calculated diet DE content. Thus, diet formulation must be adjusted with a decline in feed ingredient quality. Thus, low quality grains can be used effectively in swine diets, considering:

Ingredient DE content has been predicted using chemical analyses (or perhaps NIRS);

The ingredient specifications have been altered during least-cost diet formulation;

The diets have been re-formulated to ensure that the dietary DE content required for a predictable performance is met. For example, if the predicted barley DE content is lower than the average book value for barley DE, additional energy in the form of canola oil or tallow should be added to the diet to ensure that that actual dietary DE content is at the desired level.
Only then can the grower-finisher pig achieve the energy intake required to maintain protein deposition.

Value-added processing
As discussed previously, the variation in barley or wheat DE content is mostly due to a change in energy digestibility and not a change in gross energy. A decrease in energy digestibility has been linked to an increase in fibre content (Zijlstra et al. 1999; Fairbairn et al., 1999). Therefore, ingredient or diet processing techniques that increase energy digestibility might add nutritional and economic value to low quality wheat or barley. Value-added processing of low quality ingredients might include reducing particle size by grinding more finely (Oryschak et al 2002) or supplementation of fibre-degrading enzymes (Zijlstra et al. 2000).
Regular grinding results in a mean particle size of 700 to 900 microns; however, there may be merit in reducing the particle size of low quality grain to 600 microns or below. Due to the higher fibre content in low quality wheat or barley, supplementation of enzymes to digest fibre might be more beneficial in ingredients with a low or normal DE content compared to ingredients with a high DE content. The impact of value-added processing should be validated using the 2002-harvest, although some indication can be given for the expected improvement in DE content using value-added processing (Zijlstra et al. 1998),

Summary
The 2002-harvest in western Canada was poor. The amount harvested was below average and contained a large proportion of low quality grains. This manuscript focused on determining wheat and barley quality and the possible actions to take after identification of low quality grain. Possible actions include changing diet formulations and/or using value-added processing.

Implications
The quality of low quality grains, especially their DE content, may be predicted using equations based on chemical characteristics. The existing prediction equations should be used cautiously for now, and be validated using the 2002-harvest. Changing diet formulation might allow the use of low quality ingredients by introducing a larger portion of energy-providing ingredients. Value-added processing might further increase the effective use of low quality wheat or barley in swine diets, because their DE content will be increased and a lesser amount of expensive energy-providing ingredients will have to be included in the diet to meet the desired dietary DE content. Low quality wheat or barely may form a large proportion of the diet; thus, accurate prediction of their DE content is important. Further flexibility may be introduced by reducing the proportion of low quality grains in the diet and by including a number of other ingredients.

Effect of wheat sample, particle size and xylanase supplementation on energy digestibility of wheat fed to grower pigs

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The feed processing procedures grinding and enzyme supplementation were tested to reduce the existing variability in DE content of heat. Particle size reduction and xylanase enzyme supplementation increased energy digestibility of wheat and partially reduced the variation in energy digestibility.

What is the proper stall size for gestating sows?

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Stalls remain the primary form of housing in North America. The Canadian code of practise states that stall sizes should increase as the sow increases in body weight. This study looked at the suitability of stall size by examining the relationships among sow size, stall width and sow behaviour. Four widths of gestation stalls were used to house four classes of females based on parity and body weight. It has been suggested that gestating sows be able to lie laterally without having their udder extend into the next stall. At week 3 and week 14 a 24-hour behavioural observation was conducted concerning animal posture and whether the udder extended into the next stall while lying laterally. It was found that in early gestation, week 3, gilts and small sows in 22 inch stalls spent less than 20% of the time with udders extended into the next stall while lying laterally. Medium and large sized sows spent 30% of the time with udders extended into the next stall. At week 14, gilts and small sows housed in 22 inch stalls spent 38%-49% of the time with their udders extended into the neighbouring stall. While following the criterion that udders should not extend into the next stall more than 30% of the time, the results from this study suggest that gilts and small sows be housed in 24 inch stalls and medium and large sows be housed in 26-28 inch stalls. If it is not an option for producers to install different stall sizes, it is suggested that a stall width of 65cm be used to accommodate all sizes of gestating gilts and sows.

Voluntary feed intake and growth performance between grower pigs fed diets containing mustard meal or canola meal

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A sample of either mustard meal (Brassica juncea) or regular canola meal was included at 15% in diets fed to grower pigs for 28 days. Pigs fed mustard meal tended to have a 5% better growth performance and had a 2.5%-unit better feed efficiency and an equal fee intake than pigs fed canola meal. Mustard meal might thus be a good opportunity ingredient with minimally a nutritional value equal as canola meal.

Green House Gases and Odour Control

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Animal production units and manure storage structures are permanent sources of various gas emissions. The amount of organic matter in manure is substantial, and the decomposition of such organic matter can result in a number of gaseous by-products including acidifying gases (ex. NH3, CO2, N2O), toxic gases (ex. H2S) and offensive odours. Management and storage of manure actually contributes to green house gases (GHG). In fact, it has been estimated that production buildings are responsible for 50% of total GHG. However, the role of pork production in odour and GHG is becoming better understood. With increasing public concern regarding GHG, the Prairie Swine Centre is responding with up to date data and potential remedies. A current three year research program has been developed to demonstrate synthetic covers for earthen manure storage (EMS), reduction of GHG through diet manipulation, and installation and monitoring of shelter belt influence on air quality while making the findings available to the public.
A floating cover was installed on the two-cell EMS in July 2003. Fans were installed to provide a vacuum under the cover, sealing the plastic against the liquid. This in tern reduces the opportunity for odours or other gases to escape, while also increasing the value of manure as a fertilizer. Diet manipulation can be helpful to reduce additional emissions by incorporating current information on diet management. For example, substituting soybean meal with synthetic amino acids to reduce the available nitrogen in the urine and faeces. A shelterbelt will also be developed in summer 2004 to provide long term carbon sequestration on the site and disrupt air patterns to assist in odour dispersion from the site. Projects like this will allow pork producers easy access to promising technologies as well as valuable information on the cost and challenges of operating these best management practises.

Starch content and in vitro digestibility of barley and wheat samples differing in fibre content

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Starch content and in vitro starch digestibility were measured in three barely and three wheat samples differing in fibre content. Starch content was positively and fibre content was negatively related to DE content; however, in vitro starch digestibility indicated that starch was rapidly-degradable for all samples.

The Importance of Feed and Feeding the Lactating Sow

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Maintaining high levels of feed during lactation benefits both the current litter, subsequent letters as well as the sows overall productivity. Most problems arise in the first or second parity if the sow does not consume enough feed to meet energy requirements. If not enough feed is consumed milk production will decrease and body condition is lost as fat reserves are mobilized to synthesize milk. Loss of body fat can also compromise reproductive performance.
There are several management practises to help ensure sows are consuming enough feed during lactation to avoid weigh loss. Feeding levels and intake during gestation is unlikely to influence litter size unless feed intake is restricted significantly. The target for weight gain should be based on backfat thickness at time of weaning and her weight at weaning. All sows should have 18-20mm of backfat at time of farrowing and should be fed an extra 1kg/day at 100 days from breeding. Protein levels in the diet have shown to have an influence on feed intake as well as piglet weaning weight. For example, sows fed 12-14% CP consumed less than sows fed 16-18% CP. Several other factors have been shown to influence feed intake during lactation such as environment, number of daylight hours as well as the form in which the ration is fed. It is possible that the differences in sow productivity may be a result of feed and feeding programs over a sows reproductive lifetime.