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Effects of substitution of barley with citrus pulp on diet digestibility and intake and production of lactating ewes offered mixed diets based on ammonia-treated barley straw

  • C. Castrillo (a1), A. Barrios-Urdaneta (a1), M. Fondevila (a1), J. Balcells (a1) and J. A. Guada (a1)...


Twenty-eight lactating ewes (mean 48 (s.e. 0·37) kg live weight) were used from days 12 to 52 after lambing to evaluate the effects on digestibility and production performance of replacing barley grain with citrus pulp in diets based on ammonia-treated barley straw. Concentrates included 0·82 to 0·83 of different barley to citrus pulp proportions: 100: 0 (T1); 66: 33 (T2); 33: 66 (T3) and 0: 100 (T4), 0·115 of soya-bean meal, and urea to make diets isonitrogenous. Ewes were adapted to a common diet for 11 days after lambing, and then were given 850 g/day of each experimental concentrate together with 850 g/day of chopped barley straw for 14 days and milk production and lamb growth were recorded. During the following 14 days ewes received the same amount of concentrate but the straw was offered ad libitum and straw intake was recorded as well as milk production and lamb growth. After completing both periods, four ewes per treatment were used for total collections of faeces and urine. Apparent digestibility of organic matter and neutral-detergent fibre increased linearly (P < 0·05) with increasing levels of citrus pulp although no differences were found in the digestible organic matter content of dry matter of diets because of differences in ash content. Urinary excretion of allantoin and purine derivatives per unit of digestible organic matter intake tended to decrease with increasing inclusion of citrus pulp (proportionately by 0·15), suggesting a decrease in microbial protein synthesis, though this effect was not significant (P > 0·05). Faecal excretion of purine bases also decreased (P < 0·05) as citrus pulp inclusion increased. No treatment effect (P > 0·05) on ewe live weight, milk composition or serum glucose and 3–OH butyrate was observed when a 1: 1 straw to concentrate ratio was given, but milk production and lamb daily gain decreased linearly (P < 0·05) with increased proportions of citrus pulp in the concentrate. Similar responses were detected when straw was given ad libitum and differences among treatments in terms of straw intake were not identified. It is concluded that a lower microbial protein flow might explain in part the reduction in milk production observed when barley was replaced with citrus pulp.


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Agricultural and Food Research Council. 1993. Energy and protein requirements of ruminants. An advisory manual prepared by the AFRC Technical Committee on Responses to Nutrients. CAB International, Wallingford.
Agricultural Research Council. 1980. The nutrient requirements of ruminant livestock. Commonwealth Agricultural Bureaux, Slough.
Al-Saghier, O. A. S. and Campling, R. C. 1991. Energy and protein supplements to straw-based diets for yearling cattle: effects on straw intake and digestibility. Animal Production 52: 8392.
Aregheore, E. M. 2000. Chemical composition and nutritive value of some tropical by-product feedstuffs for small ruminants — in vivo and in vitro digestibility. Animal Feed Science and Technology 85: 99109.
Association of Official Analytical Chemists. 1990. Official methods of analysis, 15th edition. AOAC, Arlington, VA.
Balcells, J., Fondevila, M., Guada, J. A., Castrillo, C. and Surra, J. C. E. 1993. Urinary excretions of purine derivatives and nitrogen in sheep given straw supplemented with different sources of carbohydrates. Animal Production 57: 287292.
Balcells, J., Guada, J. A., Castrillo, C. and Gasa, J. 1991. Urinary excretion of allantoin and allantoin precursors after different rates of purine infusion into the duodenum. Journal of Agricultural Science, Cambridge 116: 309317.
Balcells, J., Guada, J. A., Peiró, J. M. and Parker, D. S. 1992. Simultaneous determination of allantoin and oxypurines in biological fluids by high-performance liquid chromatography. Journal of Chromatography 575: 153157.
Barrios-Urdaneta, A., Fondevila, M., Balcells, J., Dapoza, C. and Castrillo, C. 2000. In vitro microbial digestion of straw cell wall polysaccharides in response to supplementation with different sources of carbohydrates. Australian Journal of Agricultural Research 51: 393400.
Barrios-Urdaneta, A., Fondevila, M. and Castrillo, C. 2003. Effect of supplementation with different proportions of barley grain or citrus pulp on the digestive utilization of ammonia-treated straw by sheep. Animal Science 76: 309317.
Beever, D. E., Sutton, J. D., Thomson, D. J., Napper, D. J. and Gale, D. L. 1988. Comparison of molassed and unmolassed sugar-beet feed and barley as energy supplements on nutrient digestion and supply in silage-fed cows. Animal Production 46: 490 (abstr. ).
Ben-Ghedalia, D., Yosef, E., Miron, J. and Est, Y. 1989. The effects of starch and pectinrich diets on quantitative aspects of digestion in sheep. Animal Feed Science and Technology 24: 289298.
Bueno, M. S., Ferrari, E. Jr, Bianchini, D., Leinz, F. F. and Rodríguez, C. F. C. 2002. Effect of replacing corn with dehyrated citrus pulp in diets of growing kids. Small Ruminant Research 46: 179185.
Carey, D. A., Caton, J. S. and Biondini, M. 1993. Influence of energy source on forage intake, digestibility, in situ forage degradation, ruminal fermentation in beef steers fed medium-quality Brome hay. Journal of Animal Science 71: 22602269.
Carro, M. D., Valdés, C., Ranilla, M. J. and González, J. S. 2000. Effect of forage to concentrate ratio in the diet on ruminal fermentation and digesta flow kinetics in sheep offered food at a fixed and restricted level of intake. Animal Science 70: 127134.
Castrillo, C., Dapoza, C., Rubio, C. and Guada, J. A. 1995a. Effect of fish meal supplementation on body energy mobilization and milk production of ewes in negative energy balance. Animal Science 60: 532 (abstr. ).
Castrillo, C., Fondevila, M., Alibes, X. and Joy, M. 1991. Chemical treatments for upgrading lignocellulosic resources and strategies for their utilisation in ruminant feeding. In Production and utilisation of lignocellulosics (ed. Galletti, G. C.), pp. 339373. Elsevier Applied Science, London.
Castrillo, C., Fondevila, M., Guada, J. A. and Vega, 1995b. Effect of ammonia treatment and carbohydrate supplementation on the intake and digestibility of barley straw diets by sheep. Animal Feed Science and Technology 51: 7390.
DePeters, E. J., Fadel, J. G. and Arosena, A. 1997. Digestion kinetics of neutral detergent fiber and chemical composition within some selected by-product feedstuffs. Animal Feed Science and Technology 67: 127140.
Feregos, K., Zeras, G., Stamouli, S. and Apostolaki, E. 1995. Nutritive value of dried citrus pulp and its effect on milk yield and milk composition of lactating ewes. Journal of Dairy Science 78: 11161121.
Fondevila, M., Castrillo, C., Guada, J. A. and Balcells, J. 1994. Effect of ammonia treatment and carbohydrate supplementation of barley straw on rumen liquid characteristics and substrate degradation by sheep. Animal Feed Science and Technology 50: 137155.
Fonseca, A. J. M., Dias-da-Silva, A. A. and Lourenço, A. L. G. 2001. Effects of maize and citrus-pulp supplementation of urea-treated wheat straw on intake and productivity in female lambs. Animal Science 73: 123136.
Harrison, D. G. and McAllan, A. B. 1980. Factors affecting microbial growth yields in the reticulo-rumen. In Digestive physiology and metabolism in ruminants (ed. Ruckebusch, Y. and Thivend, P.), pp. 205226. MTP Press Limited, Lancaster.
Hill, J. and Leaver, J. D. 1999. Energy and protein supplementation of lactating dairy cows offered urea treated whole-crop wheat as the sole forage. Animal Feed Science and Technology 82: 177193.
Leiva, E., Hall, M. B. and Van Horn, H. H. 2000. Performance of dairy cattle fed citrus pulp or corn products as sources of neutral detergent-soluble carbohydrates. Journal of Dairy Science 83: 28662875.
Romney, D. L., Blunn, V., Sanderson, R. and Leaver, J. D. 2000. Feeding behaviour, food intake and milk production responses of lactating dairy cows to diets based on grass silage of high or low dry-matter content, supplemented with quickly and slowly fermentable energy source. Animal Science 71: 349357.
Statistical Analysis Systems Institute. 1998. SAS companion for the Microsoft Windows Environment, version 6·12. SAS Institute Inc., Cary, NC.
Stritzler, N. P., Jensen, B. B. and Wolstrup, J. 1998. Factors affecting degradation of barley straw in sacco and microbial activity in the rumen of cows fed fibre-rich diets. III. The amount of supplemental energy. Animal Feed Science and Technology 70: 225228.
Sutton, J. D., Bines, J. A., Morant, S. V., Napper, D. J. and Givens, D. J. A. 1987. Comparison of starchy and fibrous concentrates for milk production, energy utilization and hay intake by Friesian cows. Journal of Agricultural Science, Cambridge 109: 375386.
Van Soest, P. J., Robertson, J. B. and Lewis, B. A. 1991. Methods for dietary fiber, neutral detergent fiber and nonstarch polysaccharides in relation to animal nutrition. Journal of Dairy Science 74: 35833597.
Williamson, D. H. and Mellanby, J. 1963. D-(-)-3-hydroxybutyrate. In Methods of enzymatic analyses (ed. Bergmeyer, U. H.), pp. 459461. Academic Press, New York.



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