M.W.A. Verstegen

DIETARY PROTEIN AFFECTS NITROGEN EXCRETION AND AMMONIA EMISSION FROM SLURRY OF GROWING-FINISHING PIGS

The effects of dietary protein on nitrogen excretion and ammonia emission from slurry of growing-finishing pigs were studied both in vitro and in a pig house. The three diets had similar contents of NE, minerals, vitamins and ileal digestible lysine, methionine + cystine, threonine and tryptophan, but differed in CP content (16.5, 14.5 and 12.5%). In the balance experiment, 18 castrated males of about 55 kg body weight were allotted to the three diets. The experiment lasted 9 weeks, which were divided into three 3-week periods. In each period, urine and faeces were collected separately for 7 days in metabolism cages and mixed as slurry. A sample of this slurry was placed in a laboratory system to measure ammonia emission for 7 days. In the barn experiment, 216 pigs were housed in three compartments and fed the experimental diets. Ammonia emission was measured directly from the compartments for 7 days during each of the 3-week periods. There was no effect of dietary CP level on faecal nitrogen excretion. Urinary nitrogen excretion and slurry pH decreased when dietary CP decreased. Both balance and barn experiments showed similar effects of dietary CP on ammonia emission from slurry. Ammonia emission was reduced by 10-12.5% for each percent decrease in dietary CP. It is concluded that lowering dietary CP and supplementing essential amino acids while maintaining normal growth rate reduces urinary nitrogen and ammonia emission from the slurry of growing-finishing pigs.

The Wageningen Respiration Unit for Animal Production Research: A Description of the Equipment and its Possibilities

Six indirect calorimeters have been built at the departments of Animal Production of the Wageningen Agricultural University. They are used for measuring heat production and energy balances of animals at various environmental and nutritional conditions. Three sizes of chambers can be distinguished: 2 small chambers of 0.085 m3 each 2 medium chambers of 1.8 m3 each 2 large chambers of 80 m3 each.

Fermented co-products and fermented compound diets for pigs: a review

This review deals with the properties of fermented diets and their effects on growth performance and gastrointestinal environment of pigs. In addition, some possible modes of action are hypothesized. Starch and sugar rich liquid co-products have a high potential for fermenting during storage. Soaking compound feed with water is another means of achieving a fermented diet. These diets are characterized by a pH between 3.5 and 4.5, high levels of lactic acid, and, to a lesser extent, acetic acid and alcohol. Fermented diets seem to improve growth performance of pigs, compared with non-fermented diets. The exact reasons for this are not yet clear; however, some hypotheses are given. Based on a limited number of studies, fermented diets reduce the gastric pH and the number of Coliform bacteria in the gastrointestinal tract compared with non-fermented diets. Furthermore, there are some indications that fermented diets may positively affect pancreatic secretion, villus architecture, digestibility and absorption of dietary nutrients. Fermented diets may reduce the physical activity of pigs. More specific studies on the effect and modes of action of fermented diets are needed to allow firmer conclusions to be drawn. # 1999 Elsevier Science B.V. All rights reserved.

Weaning the pig: concepts and consequences

Weaning the Pig: Concepts and Consequences addresses the major issues surrounding the weaning process, both for piglets and the breeding herd, in modern-day pig production. The post-weaned pig presents many challenges to the manager, stockperson and nutritionist, and as such is a critical phase in the overall production system. Numerous challenges are also faced by the sow, which is required to be rebred as soon as possible after weaning. This book draws together summaries of research dealing with both piglets and the sow. Accordingly, the material presented covers the following areas associated with the weaning process: growth of the weaned pig, nutritional management in preparation for weaning, behavioural changes and adaptations around weaning, voluntary feed intake, digestive physiology, modulation of small intestinal integrity, the intestinal microflora and diarrhoeal diseases after weaning, intestinal immunity, nutritional requirements and intestinal requirements of the weaned pig, environmental and housing issues after weaning, saving and rearing supernumery and underprivileged piglets, and productivity and longevity of the weaned sow.

Energy Metabolism in Farm Animals

Energy plays a major part in enabling a farm animal to produce the desired products. A considerable part of the total feed is needed for its maintenance. Utilization of feed energy involves energy losses with faeces, urine, combustible gases and heat. A survey is given on how and to what extent feed energy is converted into metabolizable energy (ME) and how efficiently the ME is utilized for maintenance, work and synthesis growth, milk, eggs wool Estimates are presented of the amount of ME needed for maintenance and its betweenand within-animal variation. An equation is derived for calculation of heat production. Finally techniques used for obtaining information on energy metabolism feed conversion, comparative slaughter, complete energy balance using indirect or direct calorimetry are discussed. Special attention is paid to their advantages, disadvantages and precision. Also a method to measure the physical activity of animals is described and how energy costs of activity can be estimated.

Impact of feeding management on feather pecking in laying hens

In the near future EU-legislation will ban the use of conventional battery cages, while national legislation in some countries in Western Europe will ban beak trimming as well. The ban on battery cages and beak trimming causes an increased risk of feather pecking and cannibalism in laying hens. Many factors influence feather pecking behaviour, but this paper focuses on nutritional factors. Nutritional factors can have positive and negative effects on feather pecking behaviour in laying hens. Severe feather pecking has been demonstrated in birds that were fed a too low mineral level in the diet, a too low protein level or a too low amino acid level (methionine, arginine). Sometimes somewhat more feather pecking was found when layers were fed diets with mainly vegetable protein sources as compared with diets with protein from animal origin. Also more feather pecking may occur when the diets were fed restrictedly, fed coarsely ground, or fed as pellets. Feeding high-fibre diets, low energy diets, or roughages reduced feather pecking. Providing additional grain or straw in the litter during rearing could result in lower levels of feather pecking behaviour in adult stages. Some of these positive effects on feather pecking seem to be related to the time birds spend on feed intake and foraging. This paper gives an overview of the relationships between the occurrence of feather pecking behaviour and nutritional factors, such as diet composition and feeding strategies in laying hens.

True protein digestibility and amounts of endogenous protein measured with the 15N-dilution technique in piglet feed on peas (Pisum sativum) and common beans (Phaseolus vulgaris)

The faecal and ileal true protein digestibilities of the raw pea (Pisum sativum) varieties finale and frijaune and the ileal true protein digestibility of steam-processed common beans (Phaseolus vulgaris) were measured in piglets using the 15N-dilution technique. The faecal true protein digestibility of both pea varieties was about 97. The ileal true protein digestibility was between 93 and 95, indicating that the pea protein is almost completely enzymically digested in the small intestine. The faecal apparent protein digestibility was 85 for both varieties while at the ileal level it was 79 and 74 respectively. The lower ileal apparent protein digestibility of peas can be attributed completely to the excretion of endogenous protein. The ileal apparent protein digestibility of toasted common beans was about zero (-4); the ileal true protein digestibility was about 66. This indicates that the protein of the common bean, although toasted, was highly resistant to enzymic digestion. It was calculated that per kg ingested bean protein, 340 g undigested bean protein and 700 g endogenous protein passed the terminal ileum. The results of the present study explain why in previous experiments a strongly reduced weight gain and even weight loss was observed in piglets fed on raw and toasted common beans.

Performance and body composition of fatteningpigs of two strains during protein deficiency and subsequent realimentation

Abstract The influence of protein restriction and subsequent realimentation on protein and lipid depositionas studied. Between 28 kg and 65 kg live weight (LW ), entire male pigs of two strains (a commercial and a sire strain) were given diets either deficient or adequate in protein content. From 65 to 105 kg LW all pigs were fed a protein-adequate ration. Animals were slaughtered and dissected at start, 65 and 105 kg LW. Body composition and deposition rates of protein, lipid, lean and fatty tissue for both the restriction period (28–65 kg LW) and the realimentation period (65–105 kg LW) were calculated. Protein restriction reduced feed intake (28%), live weight gain (60%), and rate of protein (75%) and lipid deposition (15%) between 28 and 65 kg live weight. A165 kg, restricted animals had twice as much lipid and were 60 days older than controls. During realimentation, previously restricted pigs (compared to controls) had slightly (7%) reduced feed intake and 15% increased weight gain and efficiency. Protein deposition rate beyond 65 kg LW was increased by 13% and ratio of lipid to protein deposition was decreased from 1.69 to 1.23. At 105 kg, the previously restricted pigs still were older and fatter than controls, so compensation was not complete. Strains of pigs responded similarly to both restriction and realimentation. Dissection at 105 kg LW was not sensitive enough to show the effects revealed by chemical analysis. The experiment revealed that nutritional history may influence the relation between lipid deposition rate and protein deposition rate.

Influence of electrolyte balance and acidifying calcium salts in the diet of growing-finishing pigs on urinary pH, slurry pH and ammonia volatilisation from slurry

This study investigated the effects of dietary electrolyte balance (dEB=Na+K-Cl meq/kg DM) and acidifying Ca-salts on slurry pH and ammonia emission from slurry of growing-finishing pigs. Ninety gilts of about 40 kg BW were randomly allotted to 18 diets in five replicates. Two basal diets were used. Diet A had a high dEB (320 meq/kg DM) and diet B a low dEB (100 meq/kg DM). Each diet was supplemented with one of the four Ca-salts (CaCO3, CaSO4, Ca-benzoate or CaCl2) to increase Ca content by 3 or 6 g per kg of diet. Faeces and urine were collected separately in metabolism cages and mixed as slurry. In a subsample of this slurry, pH and ammonia emissions were measured in a laboratory system. The low dEB diet produced urine and slurry with lower pH, and less ammonia was emitted from the slurry. Replacing dietary CaCO3 by CaCl2, CaSO4 and Ca-benzoate reduced ammonia emission by 30, 33 and 54%, respectively. It is concluded that ammonia emission can be reduced by decreasing dEB level and adding CaSO4 and CaCl2 to the diet instead of CaCO3. The most profound effect is achieved when CaCO3 is replaced by Ca-benzoate.

Apparent ileal dry matter and crude protein digestibility of rations fed to pigs and determined with the use of chromic oxide (Cr2O3) and acid-insoluble ash as digestive markers.

Two experiments were conducted to determine apparent ileal DM and crude-protein (CP) digestibilities in rations fed to pigs. An evaluation was made of Cr2O3 and HCl-insoluble ash as digestive markers. In addition, the effects of body weight (BW) on apparent ileal DM and CP (N x 6.25) digestibilities were studied. In Expt 1, thirteen barrows averaging 35 kg BW were fitted with post-valve T-caecum (PVTC) cannulas to determine the apparent ileal DM and CP digestibilities of a wheat gluten-bran ration (B2) and a soyabean-meal ration (E1). Immediately after morning feeding ileal digesta samples were collected on an hourly basis for a total of 12 h. Subsequently. N and marker contents were determined in the samples. The postprandial patterns of N and Cr passage were more similar than those of N and HCl-insoluble ash. Therefore Cr2O3 is more suitable as a marker than HCl-insoluble ash. The apparent ileal CP digestibility coefficient of ration B2 derived using Cr2O3 as a marker was significantly (P < 0.05) higher by 0.018 compared with the value obtained using HCl-insoluble ash. The corresponding values for ration E2 obtained using Cr2O3 and HCl-insoluble ash were both 0.825. In Expt 2, apparent ileal DM and CP digestibilities were determined in eighteen rations using twelve barrows also fitted with PVTC cannulas (BW from 40 to 100 kg). The protein sources for these rations were from different groups of feedstuffs. In four and three of the rations apparent ileal DM and CP digestibilities respectively were significantly different (P < 0.05) when assessed using the two markers. The digestibility coefficients were not systematically higher or lower for either marker. Absolute differences were < 0.049 on average. Significant effects of live weight on apparent ileal CP digestibilities were found.