Reduction In Crude Protein Content Research Articles

122. Reduction in crude protein content and soybean meal inclusion: What effects on performance and nitrogen emissions in broiler chickens?

122. Reduction in crude protein content and soybean meal inclusion: What effects on performance and nitrogen emissions in broiler chickens?

Antioxidant Capacity, Inflammatory Response, Carcass Characteristics and Meat Quality of Hu Sheep in Response to Dietary Soluble Protein Levels with Decreased Crude Protein Content.

Manipulating dietary nutrients, especially protein fractions, holds significance in enhancing the antioxidant capacity and immunity function of ruminants. This study investigated the impact of dietary adjustments in soluble protein (SP) levels, in conjunction with a reduction in crude protein (CP) content, on the antioxidant capacity, inflammatory response, carcass characteristics, and meat quality of sheep. This study had four dietary treatments, including a control diet (CON) adhering to NRC standards with a CP content of 16.7% on a dry matter basis and three diets with an approximately 10% reduction in CP content compared to CON with SP levels (% of CP) of 21.2 (SPA), 25.9 (SPB) and 29.4% (SPC), respectively. Thirty-two healthy male Hu sheep, with an initial live weight of 40.37 ± 1.18 kg and age of 6 months, were randomly divided into four groups to receive these respective diets. Our data revealed no significant differences in slaughter performance among treatments (p > 0.05), although low-protein treatments decreased the stomachus compositus index (p < 0.05). Compared with CON, as SP was adjusted to 21.2%, total antioxidant capacity (T-AOC) and catalase (CAT) concentrations were decreased in the serum (p < 0.05), glutathione peroxidase (GSH-Px) content was decreased in jejunum and ileum (p < 0.05), superoxide dismutase (SOD) concentration was reduced in the duodenum (p < 0.05), and malondialdehyde (MDA) content was increased in spleen and ileum (p < 0.05). On the other hand, pro-inflammatory cytokine (IL-1β, IL-6 and IL-8) contents were upregulated in the serum (p < 0.05), while immunoglobulin (IgA and IgM) contents were reduced in the duodenum (p < 0.05) with SP adjustments. Additionally, the SPB and SPC diets reduced the content of saturated fatty acids and increased the content of polyunsaturated fatty acids compared with CON (p < 0.05), along with retention in the tenderness and water-holding capacity of the longissimus lumborum muscle. In summary, reducing CP by 10% with an SP proportion of ~25-30% improved meat quality without compromising antioxidant capacity and immunity function, while lower SP levels had adverse effects.

A Comparison of Physical, Chemical, Biological and Combined Treatments for Detoxification of Free Gossypol in Crushed Whole Cottonseed

Oilseed plants such as cotton (Gossypium sp.) generate abundant biomass residues which contain significant levels of edible oil, crude proteins and other desirable biomolecules for the animal nutrition industry. The application of cottonseed cake in animal feed, a by-product of the cotton industry, is limited due to the natural presence of toxic free gossypol (FG), wherein efficient and cost-effective methods for FG detoxification are necessary. Herein, pretreatment methods for reducing FG in crushed whole cottonseed (CWCS) were compared, with residual FG quantified using a sensitive Ultra High-Performance Liquid Chromatography method for detection at trace levels in cottonseed materials. Physical treatment by autoclaving resulted in up to 96% detoxification of FG, without reduction in crude protein (CP) content. Chemical treatment with 1% and 2% Ca(OH)2 eliminated FG to as low as 0.04%, although a reduction in CP content was observed. Similarly, native fermentation, whilst reducing FG content by 99.66% after 6 days incubation, also reduced CP content. In combined physical and biological solid-state fermentation (SSF), basidiomycete fungi Ganoderma lucidum CC351, Panus lecomtei CC40, Pleurotus ostreatus CC389, Pleurotus sapidus CC28 and Pycnoporus sanguineus CC400 all degraded FG in autoclaved CWCS to trace levels often lower than obtained by individual treatments. A reduction in total lipids and increase in CP were also observed, improving nutritional quality. The most efficient fungi, P. ostreatus CC389 and P. lecomtei CC40, secreted considerable laccase and manganese peroxidase enzymes during SSF, potentially involved in FG detoxification. Cost effective, non-polluting, value-adding approaches for FG detoxification offer potential in animal feed industries.

Analysis of the significant drop in protein content in Danish grain crops from 1990-2015 based on N-response in fertilizer trials

A significant drop of 2.4–2.9 percentage-points (%-p) in crude protein content (on dry matter basis) in Danish grain crops was observed from around 1990 to 2015. The aim of the analysis was to quantify the effect of the change in N-response of varieties of winter wheat (WW) and spring barley (SB) under farmers’ conditions based on approx. 1000 fertilizer trials with WW and 500 with SB carried out in farmers’ fields from 1987 to 2015. Results indicated that for WW receiving 129−190 kg N/ha, DM yield increased 0.8-0.9 Mg/ha. The amount of harvested N in grain increased 5−11 kg N/ha, and % N in grain dropped by 0.1-0.05 %-points; the largest drop was found for low N-additions. For SB, receiving 93−129 kg N/ha, DM yield increased by 0.9–1.1 Mg/ha. The amount of harvested N in grain increased by 4−6 kg while the N % in grain dropped 0.2-0.24 %-points. For both crops, the effect of plant breeding is likely to be confounded with the effect of increased CO2. Adding up effects of changed N-response and fertilizer rates only explained part of the observed reduction in crude protein content.

VALOR NUTRITIVO DE SILAGEM DE CAPIM-PIATÃ EM MONOCULTIVO E EM CONSÓRCIO COM SORGO DE CORTE E PASTEJO

Resumo Objetivou-se avaliar a influência da idade de corte no valor nutritivo de silagem de capim-piatã em monocultivo e em consórcio com sorgo. Utilizou-se o delineamento em blocos casualizados com quatro repetições. Os tratamentos foram dispostos em esquema de parcelas subdivididas, como parcelas sistemas (capim-piatã; sorgo de corte e pastejo e consórcio) e como subparcelas as idades de corte (70, 90 e 110 dias após a semeadura). Os minissilos foram abertos aos 46 dias, avaliando-se na silagem os teores de proteína bruta (PB), fibra em detergente ácido (FDA), fibra em detergente neutro (FDN), nutrientes digestíveis totais (NDT), nitrogênio amoniacal, lignina e pH. Com o avanço da idade, ocorreu redução linear no teor de PB de 0,12; 0,08 e 0,16 unidades percentuais a cada dia após a semeadura nas silagens de sorgo, sorgo+capim e capim-piatã, respectivamente. Verificou-se aumento linear no valor de pH da silagem de sorgo + capim, em função do avanço na idade de 0,03 unidade a cada dia após a semeadura. Nas silagens de sorgo e de capim em monocultivo, o pH apresentou valores médios de 4,63 e de 5,20, respectivamente. Os sistemas com sorgo apresentam potencial para produção de silagem de boa qualidade aos 70 dias de idade.

Does a reduction in dietary crude protein content affect performance, nutrient requirements, nitrogen losses, and methane emissions in finishing Nellore bulls?

An experiment was conducted to evaluate whether a reduction in dietary crude protein (CP) content affects animal performance, energy and protein requirements, N losses, and enteric methane emission in finishing Nellore bulls. Twenty-six animals, with an average age of 20±1.0months and initial body weight (BW) of 296±8.1kg were used in this experiment. Four animals were used as baseline reference animals and were slaughtered at the beginning of the experiment. Four animals were fed at maintenance level (MAIN), whereas 18 bulls were divided into 3 groups (n=6 in each group) and were randomly assigned to the treatments consisting of three levels of CP in the diets: 10, 12, and 14% of CP. At the end of the experiment, all animals were slaughtered to evaluate their chemical body composition, energy and protein requirements, and carcass characteristics. A linear effect was observed for dietary CP level on CP intake and digestibility, while greater values were obtained for animals that were fed 14% CP. Nitrogen metabolism was affected by CP levels, where animals that were fed 12 and 14% CP had greater urinary N losses than those that were fed 10% CP. There was no effect of CP level on retained N, animal performance, and carcass characteristics among diets, and there was no effect of CP level on microbial efficiency and CH4 emissions. Thus, this study showed that for finishing bulls, the level of dietary CP did not interfere with muscle deposition and greenhouse gas emissions. The reduction of CP content in diets does not affect DM intake, animal performance, and carcass characteristics, thereby suggesting that the use of 10% of CP in diets for finishing bulls reduces their environmental impact due to a lower urinary N excretion than 12 and 14% CP-based diets. Animals that were fed 10, 12, and 14% CP diets had emissions equivalent to 3893; 3755; and 4255gd−1 of CO2, respectively, and no difference was observed among diets. Furthermore, methane emission is not affected by CP levels ranging between 10 to 14% which, on average, is 16.3gkg−1 of DM intake. Our study found that a decreased CP level did not influence animal performance, but it did decrease N losses in manure without affecting methane emissions. However, it is important to highlight that more studies are necessary to confirm these results.

Modeling ammonia emissions from dairy production systems in the United States

Dairy production systems are hot spots of ammonia (NH3) emission. However, there remains large uncertainty in quantifying and mitigating NH3 emissions from dairy farms due to the lack of both long-term field measurements and reliable methods for extrapolating these measurements. In this study, a process-based biogeochemical model, Manure-DNDC, was tested against measurements of NH3 fluxes from five barns and one lagoon in four dairy farms over a range of environmental conditions and management practices in the United States. Results from the validation tests indicate that the magnitudes and seasonal patterns of NH3 fluxes simulated by Manure-DNDC were in agreement with the observations across the sites. The model was then applied to assess impacts of alternative management practices on NH3 emissions at the farm scale. The alternatives included reduction of crude protein content in feed, replacement of scraping with flushing for removal of manure from barn, lagoon coverage, increase in frequency for removal of slurry from lagoon, and replacement of surface spreading with incorporation for manure land application. The simulations demonstrate that: (a) all the tested alternative management practices decreased the NH3 emissions although the efficiency of mitigation varied; (b) a change of management in an upstream facility affected the NH3 emissions from all downstream facilities; and (c) an optimized strategy by combining the alternative practices on feed, manure removal, manure storage, and land application could reduce the farm-scale NH3 emission by up to 50%. The results from this study may provide useful information for mitigating NH3 emissions from dairy production systems and emphasize the necessity of whole-farm perspectives on the assessment of potential technical options for NH3 mitigation. This study also demonstrates the potential of utilizing process-based models, such as Manure-DNDC, to quantify and mitigate NH3 emissions from dairy farms.

Protein content of leaf-cutting ant queens before the nuptial flight and during the post-claustral phase

Protein content of leaf-cutting ant queens before the nuptial flight and during the post-claustral phase. This study evaluated the crude protein content of queens of Atta sexdens before the nuptial flight and after the claustral phase in laboratory and field colonies. The hypothesis was that protein is used for survival of the queen and for early colony growth during the claustral phase. Additionally, the nest morphology, live biomass and adult population of field colonies were evaluated. Crude protein was determined by digestion of the organic material with sulfuric acid at high temperatures. The mean crude protein content was 123.23 ± 11.20 mg for females before the nuptial flight and 70.44 ± 12.21 mg for laboratory-reared queens after the claustral phase. The post-claustral crude protein content of field-collected queen was 55.90 ± 9.18 mg. With respect to the loss of crude protein as a function of duration of the claustral phase, laboratory-reared queens lost 52.79 mg and field-collected queens lost 67.33 mg compared to females before the nuptial flight. A positive linear correlation was observed between the weight of field-collected queens (256.4 ± 36.3 mg) and colony biomass (13.02 ± 9.12 g), but there was no correlation between biomass and nest depth (13.11 ± 3.82 cm). As expected, the present results support the hypothesis that protein is used for survival of the queen and for early colony growth, as demonstrated by the reduction in crude protein content as a function of duration of the claustral phase. To our knowledge, this is the first study to provide data of the dynamics of protein reserves in leaf-cutting ant queens during the claustral phase.

Effect of reduced dietary protein and supplementation with a docosahexaenoic acid product on broiler performance and meat quality

1. Chicken breast meat is a lean meat due to its low content of intramuscular fat (IMF) resulting in an overall lower acceptability by consumers due to a decrease in juiciness, flavour and increased chewiness. Recently, studies performed in pigs suggested the possibility of increasing IMF by decreasing dietary crude protein (CP) content, an effect possibly mediated through an increased lipogenesis.2. Dietary supplementation with lipids rich in omega 3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) may modulate an increase in the content of these fatty acids in meat from monogastric animals and, thus, promote the daily intake of n-3 LC-PUFA by humans.3. LC-PUFA are very susceptible to oxidation, resulting in off-flavours that affect meat quality and consumers’ acceptability.4. This trial was conducted to assess the effect of reducing dietary CP, from 21% to 17%, on chicken’s meat IMF content and, simultaneously, to evaluate if a complementary supplementation with a proprietary n-3 LC-PUFA source (DHA Gold™) could improve meat quality. These effects were assessed by measuring productive performance and meat quality, oxidative stability, sensory traits and fatty acid profile.5. A reduction in CP content of broiler diets, from 21% to 17%, balanced for lysine, improved performance while it was not sufficient to increase IMF content in chicken meat. In contrast, DHA Gold™ supplementation had a positive impact both in broiler productive parameters and in meat fatty acid profile.6. In addition, incorporation of 7.4% of DHA Gold™ in the diet promoted carcass yield but negatively affected chicken meat acceptability by consumers, due to a decrease of meat oxidative stability.7. Overall the data suggest that neither a dietary supplementation with DHA Gold™ nor a reduction in CP have a direct positive effect in the levels of IMF present in broiler meat.

Effects of Low Protein Diets Supplemented with High Amino Acids (Methionine or Lysine) on Performance of Broilers

Aims: This study is to evaluate the effects of high level methionine or lysine supplementation on the performance and carcass characteristics of broilers fed low crude protein diets. Study Design: The experiment employed a complete randomized design; all data generated were subjected to analysis of variance. Place and Duration of Study: The experiment was carried out at the Teaching and Research Farm of the University of Ibadan, Nigeria between April and July 2011. Methodology: One hundred and ninety two unsexed day old broiler chicks were used in a six-week feeding trial. For each study four experimental diets were formulated such that they contained methionine at four dietary levels of 0.0%, 0.35%, 0.45% and 0.55% while the other four set contained lysine at four dietary levels of 0.0%, 0.60%, 0.70% and 0.80% respectively. The crude protein (CP) levels of T1-T4 in methionine or lysine diets are 24.25%, 19.70%, 15.15% and 10.60%. Results: Results indicated that broilers fed diet 1 with normal protein level without methionine and lysine had higher (P<0.05) body weight gain compared with others. Feed conversion also had the same statistical trend. It was observed that level of crude protein, lysine and methionine significantly reduced feed intake of the broilers. It was reported that Original Research Article American Journal of Experimental Agriculture, 4(5): 525-531, 2014 526 reduction of CP levels in the diets of the broilers with methionine or lysine supplementation did not give desirable result. This supplementation resulted in reduced feed intake, poor feed conversion and reduced body weight gain of the experimental broilers. Conclusion: The aim of the poultry farmer is to achieve optimum production with least inputs. From this study, it was concluded that reduction of crude protein content supplemented with lysine or methionine in broiler diets resulted in reduced feed intake and suboptimal body weight gain of the broilers.

Estrutura e valor nutritivo de pastos de capins Tanzânia e Marandu aos 22 e 36 dias de rebrota para ovinos¹

Esta pesquisa foi desenvolvida durante a estação chuvosa no setor de caprinos do Departamento de Zootecnia da Universidade Federal do Piauí com o objetivo de avaliar a estrutura do pasto e o valor nutritivo para ovinos de pastos dos capins Marandu e Tanzânia aos 22 e 36 dias de crescimento. Foram avaliadas a massa de forragem, altura, porcentagem de folhas, de colmos e de material morto do pasto, a composição químicobromatológica, digestibilidade e o consumo de forragem por ovinos. A ocorrência de veranicos durante o período de rebrota de 36 dias resultou no menor crescimento das plantas, sem que houvesse diferença entre as idades para a massa de forragem, altura do pasto e porcentagem de folhas. O prolongamento do período de crescimento resultou em aumento na proporção de material morto no pasto, queda do valor nutritivo da forragem, com redução do teor de proteína bruta e da digestibilidade e elevação dos teores de fibras em detergente neutro e acido. O consumo de forragem foi equivalente entre as gramíneas, sendo que aos 36 dias de rebrota o consumo de nutrientes seria suficiente apenas para a mantença, e o prolongamento do período de rebrota de 22 para 36 dias leva à redução no consumo de forragem por ovinos devido à queda na qualidade da forragem, tanto do seu valor nutritivo como da estrutura do dossel.

Effects of dietary crude protein and calcium/phosphorus content on growth, nitrogen and mineral retention in broiler chickens

This experiment was conducted to examine the effect of three levels of crude protein (CP) (NRC, 15% more than NRC and 15% less than NRC) and three levels of Ca and available P (Av. P) (NRC, 15% more than NRC and 15% less than NRC) on performance of broilers from hatching until 21 days of age. The experimental design was a completely randomized design (CRD), with a 3 × 3 factorial arrangement of nine dietary treatments. Each treatment combination had four replicate pens (10 birds per pen). Results of this experiment showed that CP content had no significant effect on feed and water intake. However, body weight gain (BWG) significantly reduced and FCR increased (P < 0.05) by 15% change in CP content of diet. Fifteen percent increase in mineral content of diets had no significant effect on feed intake. However, increase in Ca and Av. P significantly increased BWG and resulted in an improved feed conversion ratio (FCR) and increased water intake. There was an interactive effect of CP by Ca and Av. P levels on feed intake, BWG and FCR. A change in CP or mineral content of the diets had no significant effect on blood parameters except for potassium concentration (K + ). Reducing CP, Ca and Av. P content of the diet significantly (P < 0.001) increased P, Ca and N retention. Reduction in CP content of the diet led to a decrease in length, P and tibia bone ash. There was an interactive effect of CP by Ca and Av. P on the retention of Ca, N and ash of tibia bone.

Redução de proteína bruta com suplementação de aminoácidos, com base no conceito de proteína ideal, em rações para alevinos de tilápia-do-nilo

Objetivou-se avaliar o efeito da redução da proteína bruta (PB) da ração com suplementação de aminoácidos, com base no conceito de proteína ideal, sobre o desempenho de alevinos de tilápia-do-nilo (Oreochromis niloticus). Utilizaram-se 396 alevinos, linhagem tailandesa, com 0,80 ± 0,17 g de peso vivo, distribuídos em delineamento de blocos ao acaso, composto de seis tratamentos (32, 31, 30, 29, 28 e 27% de PB), seis blocos por tratamento e 11 peixes por unidade experimental. As rações foram formuladas para serem isoenergéticas e isolisínicas digestíveis, mantendo-se constantes as relações mínimas dos aminoácidos com a lisina. Os peixes foram mantidos em 36 aquários de 130 L, dotados de abastecimento de água, temperatura controlada e aeração individual, e alimentados à vontade seis vezes ao dia durante 40 dias. A redução do teor de proteína bruta da ração não afetou o ganho de peso, a taxa de crescimento específico, o consumo de ração, o consumo de lisina digestível, o teor de proteína corporal, as taxas de deposição de gordura e de proteína e a eficiência de retenção de nitrogênio dos peixes. Os peixes alimentados com rações com 27% de PB apresentaram pior conversão alimentar, menor eficiência de utilização da lisina para ganho, menor consumo de nitrogênio e umidade corporal, maior eficiência protéica para ganho e mais alto teor de gordura corporal. O nível de proteína bruta da ração para alevinos de tilápia-do-nilo pode ser reduzido em quatro pontos percentuais (de 32 para 28%), pois essa redução não prejudica o desempenho dos animais, desde que as rações sejam suplementadas com aminoácidos essenciais limitantes.

The content of insoluble fibre and crude protein value of the aboveground biomass of Amaranthus cruentus and A. hypochondriacus

Twenty samples of the aboveground biomass of &lt;i&gt;Amaranthus cruentus&lt;/i&gt; (varieties Olpir, Amar 2 RR-R 150, and A 200 D) and &lt;i&gt;A. hypochondriacus&lt;/i&gt; (variety No. 1008) were analysed to determine their nutritional value during the experimental period covering five growth stages from inflorescence emergence till full ripening of grain. During plant growth, from day 80 to day 120 of cultivation, the nutritional value decreased. This was demonstrated by an increase in insoluble fibre and a reduction in crude protein content. The content of neutral detergent fibre (NDF) in the dry matter increased from 356 to 420 g/kg (&lt;i&gt;P&lt;/i&gt; &lt; 0.01); acid detergent fibre (ADF) from 238 to 286 g/kg (&lt;i&gt;P&lt;/i&gt; &lt; 0.01); acid detergent lignin (ADL) from 22.9 to 53.4 g/kg (&lt;i&gt;P&lt;/i&gt; &lt; 0.01). The content of crude protein in the dry matter of the investigated amaranth varieties decreased from 174 to 109 g/kg (&lt;i&gt;P&lt;/i&gt; &lt; 0.01). In the Czech Republic the aboveground biomass of the cultivated &lt;i&gt;A. cruentus&lt;/i&gt; and &lt;i&gt;A. hypochondriacus&lt;/i&gt; could be used as a good source of fibre and protein in animal diets when harvested in the period from day 80 to 90 of cultivation.

Comparative Rumen Degradability of Some Legume Forages between Wet and Dry Season in West Sumatra, Indonesia

An experiment was conducted to evaluate the potential nutritive value of five legume forages (leaves and twigs) in West Sumatra during wet and dry seasons. The chemical composition, in vitro dry matter (IVDMD), organic matter (IVOMD) and crude protein digestibility (IVCPD), in vitro gas characteristics and estimated metabolizable energy (ME) showed variation among legume forages and between different seasons. Crude protein (CP) ranged from 14.2 to 27.8% DM in the wet season, with a significant (p<0.05) reduction in dry season. C. pubescens, G. maculata, L. leucocephala and P. phaseloides showed the least reduction in CP content. The NDF, ADF and lignin were about 39.0, 26.5 and 6.1% DM, respectively in the wet season, and significantly (p<0.05) increased in the dry season, except for NDF of C. mucunoides and C. pubescens. For IVDMD, IVOMD and IVCPD significantly increased in the wet season, but values remained as high as over 50.0% of DM. The in vitro gas characteristics and metabolizable energy were significantly (p<0.05) higher in wet season than the dry season. During both seasons, the rate of constant (c) for G. maculata and ME content for C. pubescens and P. phaseloides were not significantly (p<0.05). Results demonstrated that P. phaseloides and L. leucocephala have a good nutritive value during both wet and dry seasons. Further studies on feeding trials are needed to quantify the animal responses when offered these legume forages. (Asian-Aust. J. Anim. Sci. 2004. Vol 17, No. 8 : 1107-1111)

Effect of cooked pigeon pea (&lt;i&gt;Cajanus cajan&lt;/i&gt;) seed meal on the performance of broiler chicks

Two hundred seven day old broilers were used to determine the effect of cooked pigeon pea seed meal (CPSM) on the performance of broiler chicks. The brown coat coloured pigeon pea seeds were cooked for one hour, sun-dried and milled. CPSM was included in the broiler starter diets 1, 2, 3, 4 and 5 at 0, 20, 30, 40 and 50% levels respectively to replace maize and soybean meal. Data on weight gain, feed intake were recorded and used to calculate the feed conversion ratio. Feed cost and cost of feed per kg weight gain was also determined. The results of this study indicated a slight reduction in crude protein content of pigeon pea seed meal after cooking. CPSM significantly (P0.05) difference in weight gain. Birds on diet 1 recorded the highest feed intake, which was significantly (P

Nutritive Evaluation of Some Fodder Tree Species during the Dry Season in Central Sudan

The potential nutritive value was studied on leaves of seven fodder trees in Central Sudan during dry season at two distinct periods, the early dry and the late. The chemical composition, mineral concentration, in vitro organic matter digestibility (IVOMD), in situ OM or nitrogen degradability and estimated metabolizable energy showed a wide variation among fodder tree species and between different periods of the dry season. Crude protein (CP) ranged from 285 to 197 g/kg DM at early dry season, with a significant reduction in late dry season. Ziziphus spina-christi and Balanites aegyptiaca showed the least reduction in CP content. The NDF, ADF and lignin were about 200, 160 and 19 g/kg DM, respectively at the early period, and significantly increased at the late period of the dry season, except for lignin of Z. spina-christi. For mineral concentration, all fodder tree leaves were rich in calcium but poor in phosphorus. In situ OM degradability significantly decreased at the late period of dry season, but values remained as high as over 600 g/kg OM. At both periods, Z. spina-christi showed the highest value, while the lowest was recorded in Acacia seyal. The IVOMD showed a similar trend to those of in situ OM degradability, except for A. seyal. The nitrogen degradability was highest in B. aegyptiaca and lowest in Z. spina-christi at both periods. A significant and positive correlation had existed between CP and IVOMD or in situ OM degradability (r=0.68, p<0.05; r=0.77, p<0.05, respectively). Also, a significant but negative correlation was found between condensed tannins and nitrogen degradability (r=-0.87, p<0.01). Results demonstrated that Z. spina-christi potentially has a good nutritive value as dry season feed or supplement, while A. seyal tends to be less promising. A. nubica and B. aegyptiaca may be a useful source for degradable protein, even though it may have a limited supply of energy to animals. A. tortilis, A. mellifera and A. ehrenbergiana may have potential value for a supplementation of energy or protein, if they were harvested in the early dry season or in wet season as preserved feed. It is highly recommended to supplement with an appropriate amount of phosphorus when these fodder trees were used. (Asian-Aust. J. Anim. Sci. 2002. Vol 15, No. 6 : 844-850)

Reducing nitrogen excretion in pigs by modifying the traditional least-cost formulation algorithm

A multi-objective optimization method based on the traditional least-cost formulation program was developed to reduce both cost and nitrogen excretion in pig diets by introducing weighted excesses of dietary amino acid in the objective function. To evaluate this method, growing–finishing diets were formulated with two balanced protein levels (90 and 130 g/kg) in two economical environments (Brittany, France and Québec, Canada) during 12 months (January–December 1995). Increasing the weight of amino acid excesses in the objective function rapidly decreases crude protein content in the formulated diets. The reduction of crude protein content is due to a better amino acid balance between non-weighted and weighted diets (81–100% versus 70–80%). This better amino acid balance in weighted diets is obtained by using more feed ingredients, essentially cereals, their by-products and synthetic amino acids. There is also a decrease in the utilization of feeds rich in protein. Increasing the weight amino acid excesses in the objective function increases relatively slowly feed cost compared to the reduction of the crude protein content. For example, increasing weighted feed cost by 6% in Brittany (France) during the year 1995 would have decreased total nitrogen excretion by 42%. In Québec (Canada), increasing weighted feed cost by 1% would have decreased total nitrogen excretion by 20%. Weighting amino acid excesses in the objective function reduced the ingredient composition variation in diets on month to month bases although there are important differences between the two economical environments studied.

Impact of Bemisia whiteflies (Homoptera: Aleyrodidae) on alfalfa growth, forage yield, and quality.

A 3-yr project was initiated in 1993 to examine the effects of insecticides and sustained whitefly, Bemisia argentifolii Bellows & Perring [aka. B tabaci Gennadius (Strain B)], feeding on alfalfa plant growth and vigor in greenhouse cage studies, and to determine the impact of natural Bemisia whitefly populations on alfalfa forage yields and quality in a large-plot field experiment. Alfalfa plant growth and vigor after exposure to imidacloprid and a mixture of fenpropathrin and acephate insecticides did not differ from untreated plants in the greenhouse. Consequently, foliar and soil applied insecticides were used to manipulate whitefly densities on alfalfa plants to measure whitefly feeding effects on plant growth and forage yield. Heavy whitefly densities on untreated alfalfa plants in the greenhouse resulted in significant reductions in relative growth rates and net assimilation rates as compared with imidacloprid-treated plants that were maintained relatively whitefly-free. Reductions in alfalfa plant growth measured between infested and treated plants were proportional to whitefly densities. Field plot results derived from three crop seasons were relatively consistent with our greenhouse trials. Both experimental approaches clearly showed that alfalfa plants exposed to high densities of whitefly immatures and adults grew at a significantly slower rate and produced less foliage. As a result of reduced growth rates, alfalfa maturity in the naturally infested plots was estimated to be approximately 7-10 d behind managed plots. Delays in maturity resulted in significant reductions in forage yields of 13-18% during August-September harvests when whitefly populations reached peak abundance. Whitefly feeding stresses also effected hay quality through the reduction of crude protein content and contamination of foliage with honeydew and sooty mold. The status of the Bemisia whiteflies as an economic pest to alfalfa is clearly evident from these studies, but the damage potential of whiteflies in the southwestern United States appears to be restricted to one or two harvest periods during the summer coinciding with peak adult populations and their dispersal from alternate host crops.

Improving Dairy Farm Sustainability I: An Approach to Animal and Crop Nutrient Management Planning

This two-part article reports on a process for integrating knowledge to develop and evaluate nutrient management plans for dairy farms. The focus is on accounting for and managing N, P, and K on a commercial farm. The case study farm was a well managed, progressive dairy farm located in central New York with 320 lactating cows (Bos taurus), 290 heifers, and 600 acres of crop land. This farm had the resources and management skills that are a model for dairy farming in the future. However, mass nutrient balances indicated that 60 to 72% of imported N, P, and K were in excess of nutrient exports from the farm; 60 to 80% of the imported nutrients were from purchased feeds. Evaluation and refinement of animal diets resulted in a reduction in crude protein content of the rations by 2 percentage points while supporting a 13% increase in milk production and a 34% decrease in total N excretion. Partial budgets projected that ration reformulation increased net farm income by $40 200. Implementation of a crop nutrient management plan was expected to decrease fertilizer purchases and application expenses by about $1350, but construction of a remote manure storage pond and custom spreading of manure resulted in a decrease of net farm income of $4000. The vast quantity of data required and the complexity of the analysis indicate that developing computerized decision aid tools will be necessary to apply the process to a large number of farms.