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Apparent Digestibility of Minerals by Lactating Cows from a Total Mixed Ration Supplemented with Poultry Litter

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Abstract

Apparent digestibility of minerals by lactating cows from a multiple-component, conventional Israeli TMR (control) and from a TMR containing 10% poultry litter (DM basis) was examined. Ten cows in early lactation were divided into two groups of similar performance (39 kg of milk/d) and fed for ad libitum intake the two TMR for 28 d. Poultry litter contributed, as a percentage of total requirements, 44.4% of Ca, 41.0% of P, 32.0% of S, 22.8% of Mg, and 25.9% of K. Apparent digestibility of the macroelements was higher for cows fed the TMR supplemented with poultry litter than for those fed the control TMR. Apparent digestibility of the control TMR was 22.3% for Ca, 29.4% for Mg, 39.1% for P, and 62.2% for S; the apparent digestibility of the treatment TMR was 30.1% for Ca, 45.6% for Mg, 45.3% for P, and 65.6% for S. Poultry litter contributed the entire requirements of Zn, Mn, and Co; 56% of Cu; and 32% of Se. The apparent digestibility of the control TMR was 15.6% for Cu, 39.6% for Zn, 8.51% for Mn, 42.8% for Co, and 41.6% for Se, and the apparent digestibility of the treatment TMR was 27.9% for Cu, 54.0% for Zn, 17.8% for Mn, 37.0% for Co, and 63.9% for Se. Poultry litter is a good source of macro- and microelements for lactating cows and, at 10% of the TMR, could ensure against mineral deficiencies.

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... Os coeficientes de absorção aparente total de cálcio relatados pela literatura, em diferentes sistemas de alimentação, foram, em média, de 33,0 a 68,0% (FIELD, 1983), 23,4% , 47,9% (VALADARES FILHO et al.,1991a), 36,2% (ARAÚJO et al., 1994), 32,8% (RABELLO et al., 1994), 15,0 a 68,0% (COELHO DA SILVA, 1995), 26,2% (BEN-GHEDALIA et al., 1996), 63,25% (MORA et al., 1996), 52,56% (ARA-ÚJO et al., 1997), 16,32% (CARVALHO et al., 1997) e 29,87% (KHORASANI et al., 1997. ...
... Os resultados médios verificados na literatura referentes à absorção aparente de Mg variaram amplamente nas diferentes dietas, sendo 18,4% (GREENE et al., 1988), 16,3% (COELHO DA SIL-VA et al., 1991), 43,7% (ROSADO,1991, 56,9% , 51,5% (ARA- ÚJO et al.,1994), 36,6% (RABELLO et al., 1994), 37,5% (BEN-GHEDALIA et al., 1996), 41,6% (MORA et al., 1996), 45,07% (ARAÚJO et al., 1997), 23,7% e 20,23% . ...
... Alguns resultados médios obtidos na literatura, referentes à absorção aparente de K, variaram amplamente entre dietas, sendo 83,4% ), 44,4% (ROSADO, 1991, 67,9% , 80,8% (ARA- ÚJO et al., 1994), 85,0% (RABELLO et al., 1994), 77,0% (RAHNEMA et al., 1994), 83,05% (BEN-GHEDALIA et al., 1996), 79,4% (MORA et al., 1996), 82,32% (ARAÚJO et al., 1997, 70,3% (CAR-VALHO et al.,1997) e 82,1% . O NRC (1989) mencionou que o coeficiente de absorção verdadeira variou de 91 a 100%. ...
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This study was to evaluate the effects of different levels of forage in the diet on the intake and apparent absorption of calcium (Ca), phosphorus (P), magnesium (Mg), potassium (K) and sodium (Na). Thirty five pure Holstein bull calves, 60 days old with initial average live weight (LW) of 78 kg, were allotted in a completely randomized experimental design with nine replicates per diet, except for the 10% forage diet, with eight replications. The animals were ad libitum fed with diets contained 10, 25, 40 and 55% of forage, on the DM basis, using chopped coast-cross (Cynodon dactylon) grass, ground corn and soybean meal, which constitutes diets with approximately 16% CP. The apparent absorption coefficients were obtained by means of digestibility trials, carried out at 120 and 180 days of the animals age, being used the chromium oxide as a marker to estimate the fecal excretion. The maximum daily intake of 10.96 g of P was estimated with 42.40% of forage in the diet. The intakes of Mg and K increased, while the Na decreased linearly and the Ca was not affected by the forage level in the diet. The apparent absorption of Ca, P, Mg and Na were not affected, while the K decreased linearly with the forage levels in the diets. The intakes of P, Mg, K and Na and apparent absorption of the K were affected by the forage levels in the diets.
... O NRC (1988) citou que a absorção verdadeira de K varia de 91 a 100%. BEN-GHEDALIA et al. (1996) observaram, em vacas lactantes, absorções aparentes de Ca, P, Mg, Na e K, variando de 22,3 a 30,1; 39,1 a 45,3; 29,4 a 45,6; 84,2 a 70,2; e 79,4 a 86,7%, respectivamente. ...
... tradas por BEN-GHEDALIA et al. (1996), ARAÚJO et al. (1994) CARVALHO (1996). SIGNORETTI et al. (1999) observaram que os coeficientes de absorção aparente de Ca, P, Mg e Na não foram influenciados pelos diferentes níveis de feno nas dietas, mas a de K decresceu linearmente (P<0,05). ...
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The effects of different levels of roughage on intake and apparent absorption of calcium (Ca), phosphorus (P), sodium (Na), potassium (K) and magnesium (Mg) were studied. Forty Holstein x Zebu calves, with initial average live weight of 60 kg, allotted to a completely randomized design, were fed concentrate and chopped coastcross (Cynodon dactylon) grass hay ad libitum in the following levels: 10; 25; 40; 55 e 90%, on a DM basis. The coefficients of apparent absorption were obtained by one experiment with two experimental periods of digestibility, accomplished at 120 and 180 days of age of the animals. The fecal dry matter excretion was estimated with chromium oxide. The intakes of Ca, P, Mg, Na and K in (g/day) showed a quadratic effect and the respective maximum intakes were estimated for 47.0, 30.0, 45.3, 41.0 and 51.8% of roughage in the diet. The apparent absorption coefficients of Ca, P and K were affected by the level of roughage, showing a quadratic effect, with the respective maximum absorptions of 58.7, 56.1 and 78.3% for the levels of 20.3, 23.1 and 45.2% of hay in the diet.
... O NRC (1988) citou que a absorção verdadeira de K varia de 91 a 100%. BEN-GHEDALIA et al. (1996) observaram, em vacas lactantes, absorções aparentes de Ca, P, Mg, Na e K, variando de 22,3 a 30,1; 39,1 a 45,3; 29,4 a 45,6; 84,2 a 70,2; e 79,4 a 86,7%, respectivamente. ...
... tradas por BEN-GHEDALIA et al. (1996), ARAÚJO et al. (1994) CARVALHO (1996). SIGNORETTI et al. (1999) observaram que os coeficientes de absorção aparente de Ca, P, Mg e Na não foram influenciados pelos diferentes níveis de feno nas dietas, mas a de K decresceu linearmente (P<0,05). ...
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Avaliaram-se os efeitos de diferentes níveis de volumoso nas dietas sobre o consumo e a absorção aparente (AP) de cálcio (Ca), fósforo (P), magnésio (Mg), sódio (Na) e potássio (K). Utilizaram-se 40 bezerros, com peso vivo médio inicial de 60 kg, distribuídos em delineamento inteiramente casualizado e alimentados à vontade com rações na base da MS, com níveis crescentes de 10, 25, 40, 55 e 90% de feno de capim-coastcross (Cynodon dactylon) picado. Os coeficientes de absorção aparente foram obtidos por intermédio de ensaios de digestibilidade, realizados aos 120 e 180 dias de idade dos animais, sendo usado como indicador o óxido crômico para estimar a excreção fecal. Os consumos de Ca, P, Mg, Na e K, expressos em g/dia, sofreram efeito quadrático, estimando-se os respectivos consumos máximos com os níveis de 47,0; 30,0; 45,3; 41,0; e 51,8% de volumoso na dieta. As absorções aparentes do Ca, P e K foram afetadas pelos níveis de volumoso nas dietas, que apresentaram comportamento quadrático e máximas absorções de 58,7; 56,1; e 78,3% para os níveis de 20,3; 23,1; e 45,2% de volumoso nas dietas, respectivamente.
... It appears therefore that a concentrate constituted using sun-dried PL and a readily degradable energy source in the rumen would therefore pose no pathogenic or toxicity problem to animals. Further, PL contains high levels of macro-and micro-elements (Ben-Ghedalia et al., 1996), and its use as a protein source may reduce the costs of mineral supplementation to dairy cows. ...
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The existing recommendation of the maturity (age 6-10 weeks, height 60-100 cm) at which Napier is fed to dairy cows is still valid as a general guideline for milk production. The use of crude protein (CP) content and digestible CP as a measure of nutritive value should be replaced by the modern protein evaluation systems. Napier-based diets supported rumen pH and ammonia N concentrations suitable for maximum rumen microbial growth and activity and for optimal organic matter digestibility and feed intake. The efficiencies of rumen microbial protein synthesis were 25, 44 and 168 g N/kg truly fermentable organic matter while the total protein digested in the intestines was 70, 90 and 80 g/kg dry matter (DM) for Napier, legumes and oil meals respectively. Napier-only diet (60-70 g CP/kg DM) supported a mean daily milk yield of 6.8 kg/cow which was accompanied by live-weight loss (-0.44 kg/cow/day). The concentrate supplemented cows produced more milk (9.5 vs 6.6 kg/cow/day) but lost more weight (-0.48 vs -0.37 kg/cow/day) than the Leucaena-supplemented cows. The potential for prediction of yield, nutritive value and milk yield by dairy cows, and the need for more research on dairy production from Napier-based diets are discussed.
... It appears therefore that a concentrate constituted using sun-dried PL and a readily degradable energy source in the rumen would therefore pose no pathogenic or toxicity problem to animals. Further, PL contains high levels of macro-and micro-elements (Ben-Ghedalia et al., 1996), and its use as a protein source may reduce the costs of mineral supplementation to dairy cows. ...
Article
eekly data on various parameters of Napier grass on-station (irrigated) and onfarm (rain-fed) were pooled and assessed by linear and quadratic regressions. The dry matter (DM) yield could be accurately estimated using age or height whereas in vitro organic matter digestibility (OMD) was predicted better from cell-wall fractions and crude protein content. Prediction of DM yield was more accurate than that of in vitro OMD. Multiple regression equations accounted for more variations in DM yield, in vitro OMD and in vivo digestible organic matter than equations derived from single independent variables. Some of the regression equations could accurately predict DM yields and in vitro OMD at different years on-station. However, prediction of DM yield on-farm was less accurate and possible only for the high rainfall districts.
... It appears therefore that a concentrate constituted using sun-dried PL and a readily degradable energy source in the rumen would therefore pose no pathogenic or toxicity problem to animals. Further, PL contains high levels of macro-and micro-elements (Ben-Ghedalia et al., 1996), and its use as a protein source may reduce the costs of mineral supplementation to dairy cows. ...
Article
In Kenya, dairy production is mainly in the medium and high potential agricultural areas, which occupy about 17 % of the country's land. Due to high population pressure in these areas, smallholders (2-3 ha) form 80 % of the population. Napier grass (NG) has been identified to be a suitable fodder for these areas due to its high dry matter yield. The current recommendation to feed NG to cows at a height from 60 to100 cm (age, 6-10 weeks) does not take into account factors such as amount of rainfall which may influence yield and quality of the grass. Therefore poor quality and inadequate amount of feeds available to cows are common problems resulting in low levels of milk production (3-5 kg cow -1</SUP>day -1</SUP>). Although supplementation is advocated to improve milk production on NG based diets, concentrates are too expensive and high-protein legumes and fodder trees are not available in adequate quantities for supplementation of cows. As a consequence farmers are using poultry litter as an alternative and cheap sources of protein. Information on home-made concentrates using poultry litter as a source of protein, which amounts to supplement, what levels of milk production to expect and economics of production in the wet and dry seasons is therefore required.The overall objective of the study was to improve smallholder milk production in the medium and high rainfall areas through utilization of napier grass at optimal maturity and supplementation using poultry litter based concentrate. A review paper indicated the need to identify specific optimal stages of maturity for feeding NG to cows in the medium and high rainfall areas and that more work on milk production should establish technical and economic levels of supplementation. Digestibility was improved by supplementing NG at early maturity (120 g CP kg -1</SUP>DM) with soyabean meal. This implies that feeding young grass to animals will not support optimal rumen microbial protein yields resulting in low production levels. Hence the need to identify stage of maturity with optimal amounts of energy and protein. It was shown, based on crude protein: digestible organic matter ratio, that NG should be fed earlier in medium (height, 50-60 cm; age, 7-8 weeks) than high (height, 130-140 cm; age, 9-10 weeks) rainfall areas. The digestibility of NG was accurately estimated from fibre fractions (r 2</SUP>= 0.86; rsd = 23.56; P < 0.001) or crude protein content (r 2</SUP>= 0.71; rsd =27.85; P < 0.001) on-station. Also, its dry matter yield was accurately estimated from age (r 2</SUP>= 0.89; rsd = 1.27; P < 0.001) or height (r 2</SUP>=0.85; rsd = 1.54; P < 0.001) on-station. Farmers could use equations from this study to accurately estimate dry matter yield from height (r 2</SUP>= 0.51; rsd =0.77; P < 0.01) or age (r 2</SUP>= 0.39; rsd = 0.86; P < 0.01) of NG in the high rainfall areas.Information on rumen degradation and estimated intestinal protein digestion indicated that supplementing cows fed NG with sunflower seed meal based concentrate (SFBC) or purchased concentrate would support moderate milk yields. However, supplementation with poultry litter or concentrate compounded using poultry litter (PLBC) as a source of protein would result in only low milk yield. To sustain the same level of production, cows fed NG at advanced maturity (dry seasons) should be offered supplements containing about 30 g kg -1</SUP>DM more of protein digested in the intestines than cows fed the grass at the recommended medium maturity (wet seasons). High feed intake and concentration of volatile fatty acids were achieved at rumen ammonia concentration levels below the level of 100 mg l -1</SUP>when steers fed NG were supplemented with PLBC or SFBC. The acetate: propionate ratios (3.6-3.9: 1) for these diets were lower than the value required for maintaining milk butter fat content. To improve on feed intake and digestion, PLBC should be supplemented to cows fed NG at medium maturity while SFBC should be used on cows fed the grass at advanced maturity.It was not profitable, at the current market prices, to produce milk from NG at advanced maturity (dry seasons). Maximum profit was achieved when cows fed NG at medium maturity (wet seasons) were supplemented with 1 kg of dry matter of PLBC. Cows fed NG and supplemented with PLBC produced 3.5 % less milk than cows supplemented with SFBC. However, milk production profit was 22 % higher for cows supplemented with PLBC than for cows supplemented with SFBC. Milk production profit in rural areas was 68 % lower than in areas near urban centres. Use of PLBC would therefore lower cost of milk production in dairy cows fed NG based diets.
... La industria avícola genera gran cantidad excretas en las camas; éstas se han usado como alimentos en raciones para rumiantes como fuente de nitrógeno (19 a 32% proteico y no proteico 48,9 a 54,6% de la PB total, Kelleher et al., 2002;Mekasha et al., 2002;Chaudhry et al., 1998), minerales, materia seca (MS, 83,1 a 90,1%) y materia orgánica (MO, 79 -82%) según Chaudhry et al., 1998;Fontenot, 1979y Ben-Ghedalia et al., 1996. Cuando se usa la Cp sin procesar, es más barata, pero se corren riesgos sanitarios con patógenos (salmonellas o coccidias, p. ej.). ...
Article
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The effect on intake and digestibility of increasing levels of poultry litter (Cp), corn byproduct meal (Hm) or rice polishing (Pa) and sugarcane ammoniated bagasse (Ba, 40%) in rations for growing lambs in total confinement was determined. A factorial arrangement 2x4 Latin square design, with 8 sheep cannulated in rumen, was used, incorporating Hm or Pa (48, 39, 30 and 21% in both cases) and Cp (11.4, 20.4, 29.4, and 38.4%). Dry matter intake was higher in rations with Cp and Hm with respect to Cp and Pa (10- 12.1% of metabolic weight for Hm vs. 7.6-9.3% for Pa) and for organic matter (MO) intake from 8.1 to 8.5% of metabolic weight for Hm and 5.8% to 6.4% for Pa; the apparent digestibility (DA) of dry matter was 34.2-43% and 67.8-67.1% for MO in rations with Hm vs. 30.5-37.2% and 65.5-66.1% respectively for Pa. The ruminal pH and amoniacal nitrogen levels, were not indicative of acidosis or ammonia poisoning, which was consistent with normal blood physiology for rations with Cp and Hm. Results indicate that Hm and Ba rations with Cp allowed consumption and digestibility of nutrients within the normal range for lambs, without risk to animal health, which did not occur with the ratios containing Pa and Cp.
... Evidence in the literature of the bio-availability of Se in poultry manure is limited. In a digestibility study with dairy cows consuming a diet containing I}Vo poultry litter which contained 0.9 mg Se/kg DM, Ben-Ghedalia et al. (1996) concluded that Se in the litter 'was highly digestible'. Angus et al. (I97 8) reported substantially higher Se concentration in the livers of lambs receiving 60Vo broller litter in their diets compared to lower levels of litter inclusion. ...
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Two trials were conducted to establish whether selenium (Se) present in broiler litter is available to sheep consuming the litter. In both trials the treatments were pure broiler litter or litter mixed with 7.5% or 15% of molasses. The first trial was a partial digestion study using litter containing 1.0mg Se/kg dry matter (DM). The double marker technique was used to follow Se flow through the digestive tract with ytterbium as solid phase marker and chromium as liquid phase marker. Between 28% and 53% of dietary Se disappeared between the abomasum and ileum and between 2% and 28% between the ileum and the faeces. None of the differences between treatments were statistically significant. The apparent digestibility of Se in the broiler litter was 52%, 47% and 52% for the 100%, 92.5% and 85% litter treatments, respectively. In the second trial individually fed sheep received the experimental diets for 83 days. The broiler litter contained 0.68mg Se/kg DM. Selenium concentrations in blood and plasma increased with time. At slaughter, Se concentrations were measured in the livers, kidney cortices and cardiac muscles. Although the sheep consumed more (P
... La industria avícola genera gran cantidad excretas en las camas; éstas se han usado como alimentos en raciones para rumiantes como fuente de nitrógeno (19 a 32% proteico y no proteico 48,9 a 54,6% de la PB total, Kelleher et al., 2002;Mekasha et al., 2002;Chaudhry et al., 1998), minerales, materia seca (MS, 83,1 a 90,1%) y materia orgánica (MO, 79 -82%) según Chaudhry et al., 1998;Fontenot, 1979y Ben-Ghedalia et al., 1996. Cuando se usa la Cp sin procesar, es más barata, pero se corren riesgos sanitarios con patógenos (salmonellas o coccidias, p. ej.). ...
Article
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Se determinó el efecto sobre el consumo y digestibilidad aparente de niveles crecientes de cama de pollo (Cp) con harina gruesa de subproductos de maíz (Hm) o pulitura de arroz (Pa) y bagacillo de caña amonificado (40%, Ba), en raciones para corderos en crecimiento en confinamiento total. Se realizó un experimento en un arreglo factorial 2x4 en diseño de cuadrado latino con 8 corderos canulados en el rumen, incorporando Hm o Pa (48, 39, 30 y 21%, en ambos casos) y Cp (11,4; 20,4; 29,4 y 38,4%). Las raciones con Cp y Hm fueron más consumidas que las de Cp y Pa (10 a 12,1% del peso metabólico en materia seca (MS), para Hm vs. 7,6 a 9,3% para Pa) y para la materia orgánica (MO) 8,1 a 8,5% del peso metabólico para Hm y 5,8 a 6,4% para Pa; respecto a la digestibilidad aparente (DA) se obtuvo un 34,2 a 43% de la MS y 67,8 a 67,1% de la MO para raciones con Hm vs. 30,5 a 37,2% de la MS y 65,5 a 66,1% de la MO para raciones con Pa. Se apreció que el pH y el nitrógeno amoniacal, no alcanzaron los valores indicativos de acidosis ni de intoxicación con amoniaco, lo cual se correspondió con valores normales de su fisiología sanguínea para raciones con Cp y Hm. Los resultados indican que Hm y Ba en raciones con Cp permitieron un consumo y digestibilidad de los nutrientes dentro de rangos normales para corderos, sin riesgos para la salud del animal, lo cual no ocurrió con las raciones que contenían Pa y Cp.
... It appears therefore that a concentrate constituted using sun-dried PL and a readily degradable energy source in the rumen would therefore pose no pathogenic or toxicity problem to animals. Further, PL contains high levels of macro-and micro-elements (Ben-Ghedalia et al., 1996), and its use as a protein source may reduce the costs of mineral supplementation to dairy cows. ...
... It appears therefore that a concentrate constituted using sun-dried PL and a readily degradable energy source in the rumen would therefore pose no pathogenic or toxicity problem to animals. Further, PL contains high levels of macro-and micro-elements (Ben-Ghedalia et al., 1996), and its use as a protein source may reduce the costs of mineral supplementation to dairy cows. ...
Article
The digestibility of Napier grass (var. Bana) was determined from the third to 15th weeks of growth under two watering regimens which simulated the medium (800 mm) and high (1200 mm) rainfall areas of Kenya. The watering regimen, maturity and supplementation affected digestibility of the grass. Digestibility was increased by supplementation from the fifth and sixth week of growth for the low- and high-watered grass, respectively. It was concluded that Napier grass should not be used for milk production beyond 11 and 12 weeks of growth in the medium and high rainfall areas, respectively.
... Absorption of cobalt as found in the current study was 1.7-2.1 % and fell in the range 1-2 % as reported by Van Bruwaene et al. [34]. Absorption of iron and molybdenum was positive as reported by Ben-Ghedalia et al. [35]. However, apparent absorption of manganese was negative as reported by Solomon et al. [36] in sheep. ...
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Background The aim of the present study was to determine the effects of feeding trace mineralsfortified mixed microbial culture (TMC) on ruminal fermentation, nutrient digestibility, blood electrolyte status, nitrogen balance, and trace mineral balance in sheep. Methods Mixed microbes [0.6 % (v/w) of Enterobacter sp., Bacillus sp., Lactobacillus sp., and Saccharomyces sp.] were cultured with 99 % feedstuffs and 0.4 % trace minerals including zinc and copper for ensiling. Six sheep (a mean body weight of 46.5 ± 1.2 kg) were fed two diets: a control diet (concentrate mix and rye straw) and an experimental diet (a control diet + 3.1 % TMC). Results TMC feeding did not induce negative effects on ruminal fermentation, nutrient digestibility, blood electrolytes, and nitrogen balance in sheep. Feeding with TMC increased the intake of trace minerals (p < 0.05) and did not affect absorption of trace minerals in the whole digestive tract. Feeding with TMC increased fecal excretion and absorbable intake, and retention of zinc and copper (p < 0.05) by 71 % and 77 %, respectively. Conclusion Feeding with TMC resulted in higher zinc and copper bioavailability and retention without any adverse effects on sheep performance.
... A pesar de que algunos autores (Ben-Ghedalia et al., 1996), han encontrado concentraciones de cobre en la CP que resultan tóxicos para el animal. Sin embargo, la literatura no indica la presencia de vacunos intoxicados por altos niveles de cobre, y la razón se puede atribuir al hecho de que cuando se mezcla la CP con otros ingredientes (como sugiere hacerse para garantizar su mejor uso), el elemento que en la CP se encuentra a niveles tóxicos, se diluye en la ración y pierde su efecto dañino. ...
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O objetivo deste trabalho foi avaliar os efeitos do nível de volumoso na dieta (30% e 70%) e da duração do período experimental (14 e 21 dias) sobre a absorção aparente (AA) parcial e total de cálcio (Ca), fósforo (P), magnésio (Mg) e potássio (K) e sobre o coeficiente de digestibilidade aparente (CDA) parcial e total da matéria seca (MS) em bovinos. Utilizaram-se 4 novilhos da raça Holandês-Preto-e-Branco implantados com cânulas ruminal e duodenal. O delineamento experimental utilizado foi o quadrado latino 4 x 4. A dieta rica em concentrado apresentou maior CDA intestinal e total (p < 0,01) para MS e AA ruminal e total (p < 0,01) para P. A duração do período experimental afetou a AA intestinal e total (p < 0,05) de Ca, que foi maior para o período experimental de 21 dias. Houve interação entre o nível de volumoso na dieta e a duração do período experimental, em que observou-se maior AA intestinal e total (p < 0,05) de Ca para dietas com baixo volumoso.The objective of this study was to evaluate the effects of forage levels in diet (30% and 70%) and experimental periods (14 and 21 days) on the total and partial apparent absorption (AA) of calcium (Ca), phosphorus (P), magnesium (Mg) and potassium (K) and on the partial and total coefficient of apparent digestibility (CAD) of dry matter (DM) in cattle. Four Holstein steers fitted with ruminal and duodenal cannulas were used. The experimental design was a 4 x 4 Latin square. High concentrated diets showed higher intestinal and total CAD (p < 0.01) to DM and ruminal and total AA (p < 0.01) to P. The experimental period affected intestinal and total (p < 0.05) AA of Ca that was higher for of 21 days experimental period. There was interaction between forage level and experimental period where higher intestinal and total AA of Ca (p < 0.05) for diets with low forage was observed.
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A study was conducted using a randomized complete block design to determine feed intake, live-weight changes, milk yield and cost of milk production in Friesian cows fed napier grass (NG) at 10 weeks (MNG) or 15 weeks (ONG) of maturity. The MNG or ONG was supplemented with equal amounts of sunflower (SFBC) or poultry litter (PLBC) based concentrates in experiment 1, while in experiment 2, the MNG was supplemented with graded levels of the PLBC. In experiment 1, the intakes of total organic matter (TOMI) was lower (135.9 vs. 137.7 g kg W0.75) while intake of total crude protein (TCPI) was greater (16.6 vs. 12.0 g kg W0.75) for MNG than ONG diets (P<0.001). The TOMI (137.8 vs. 135.8 W0.75) and TCPI (14.3 vs. 14.2 W0.75) were higher for SFBC than PLBC diets (P<0.05). The yield of milk corrected for butter fat (FCM) was higher (11.0 vs. 5.7 kg cow−1 day−1) for MNG than ONG diets (P<0.001). In experiment 2, the TOMI (112.8 vs. 130.6 g kg W0.75) and the TCPI (12.2 vs. 16.1 g kg W0.75) were lower for MNG only diet than the mean of the supplemented MNG (P<0.001). The MNG only diet supported lower yields of FCM (7.7 vs. 10.7 kg cow−1 day−1) than the mean of the supplemented MNG (P<0.001). Although supplemented cows fed MNG diets gained weight, those fed supplemented ONG diets or MNG only diet lost weight. Feeding of supplemented ONG resulted in loss of revenue while supplementing with PLBC had higher profits than SFBC. We concluded that use of the PLBC would lower costs and improve milk production in dairy cows fed NG-based diets.
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Healthy, pluriparous, cyclic Marwari does (6) were used to investigate the changes in Zn, Cu and certain biochemical parameters during different physiological stages. Blood samples were collected during oestrous cycle, on the day of mating, gestation period (fortnightly up to fourth month, weekly during last month), day of kidding and up to 1 month of lactation period. In this study, glucose and protein profile did not change significantly between different phases of oestrus cycle, the activity of transaminases was significantly high during the follicular phase of oestrus cycle. Glucose concentration was significantly high during early and late gestation and attained significantly lowest level on the day of kidding. The activity of transaminases remained significantly low up to third month of gestation while on day of kidding, the activity increased significantly. Total protein level decreased progressively during fifth month of gestation period. However, it increased significantly at the beginning of the lactation. Up to 105 days of gestation period, albumin concentration decreased while globulin concentration increased. Albumin concentration tended to increase and attained normal value at term. However, the globulin decreased to term and lactation period. Zinc concentration remained low up to third month of gestation. At fourth month of gestation it increased significantly and remained high up to first week of post-partum period. Copper concentration showed increasing trend from third month of gestation and attained significantly higher level in the mid of fifth month of gestation. Thereafter it decreased and remained low up to first week of lactation.
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The effect on intake and digestibility of increasing levels of poultry litter (Cp), corn byproduct meal (Hm) or rice polishing (Pa) and sugarcane ammoniated bagasse (Ba, 40%) in rations for growing lambs in total confinement was determined. A factorial arrangement 2x4 Latin square design, with 8 sheep cannulated in rumen, was used, incorporating Hm or Pa (48, 39, 30 and 21% in both cases) and Cp (11.4, 20.4, 29.4, and 38.4%). Dry matter intake was higher in rations with Cp and Hm with respect to Cp and Pa (10-12.1% of metabolic weight for Hm vs. 7.6-9.3% for Pa) and for organic matter (MO) intake from 8.1 to 8.5% of metabolic weight for Hm and 5.8% to 6.4% for Pa; the apparent digestibility (DA) of dry matter was 34.2-43% and 67.8-67.1% for MO in rations with Hm vs. 30.5-37.2% and 65.5-66.1% respectively for Pa. The ruminal pH and amoniacal nitrogen levels, were not indicative of acidosis or ammonia poisoning, which was consistent with normal blood physiology for rations with Cp and Hm. Results indicate that Hm and Ba rations with Cp allowed consumption and digestibility of nutrients within the normal range for lambs, without risk to animal health, which did not occur with the ratios containing Pa and Cp.
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The association between the combination of age and physiological status of dairy Nubian goats, pregnancy or lactation and blood concentration of zinc (Zn) and copper (Cu) was investigated. The animals were divided into (a) young (4-6 months old), (b) adult (9-12 months old), (c) pregnant (within 50 days of their first pregnancy and (e) lactating animals grouped according to parity (up to 50 days after first, second or third kidding). Each group or sub-group consisted of five animals. The data analysis revealed that plasma Zn concentration decreased (3.91-1.12mg/l) significantly with increase in age. There was a significant increase in Zn levels in high yielders compared to low ones (2.00-6.59mg/l). Cu plasma levels increased (5.01-3.17mg/l) significantly in adult compared to young animals but decreased (5.01-4.13mg/l) significantly after first kidding compared to second and third kidding as well as in pregnant animals. It can be shown that the different physiological states would impose certain demands on animal needs for these trace elements and hence adequate amounts in the diet should be accounted for to achieve the best animal performance.
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Three metabolism trials were conducted to determine the effects of Al as sulfate (SO4), chloride (Cl) and citrate on metabolism of Al, Mg, Ca and serum concentrations of Mg and Ca. Twelve wether lambs, equipped with rumen cannulas and blocked by breeding and weight, were allotted randomly to the following six treatments during each of three trials: 0, 1,000 and 2,000 pm Al as SO4 or Cl; or 2,000 ppm Al as citrate. Treatments were administered in 200 ml of deionized water twice daily in divided doses via rumen cannula. Lambs were fed 1,000 g/d of chopped tall fescue hay (Festuca arundinacea, Schreb. IFN 1-09-187). Aluminum, Mg and Ca in feces and urine, and Mg and Ca in blood serum were determined daily over the 10-d treatment period. Means were calculated for d 6 through d 10. By d 6, serum Mg was lowered (P less than .05) for lambs administered 2,000 ppm Al as citrate. Serum Ca was not affected by Al treatments. Neither Mg nor Ca absorption was significantly affected by Al treatment. Urinary excretion of Ca increased linearly (P less than .001) with all treatments. Absorption of Al occurred with all forms of the element and was highest for Al2(SO4)3, expressed as percentage of intake.
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Full-text available
Five lactating Holstein cows with ruminal and duodenal cannulas were used in a 5 x 5 Latin square to determine the site of mineral absorption and effects of sources and amount of dietary fat on apparent absorption. Cows were fed (DM, 17.4 +/- .8 kg/d) chopped alfalfa hay, alfalfa haylage, corn silage, and concentrate at 1:1:1:2 (DM) at 12-h intervals. Calcium salts of palm fatty acid distillate (CS) or animal-vegetable (AV) fat were 0% (control), 2.5% (low, L), or 5.0% (high, H) of the diet DM. After 2 wk of adaptation, duodenal and fecal grab samples were collected at 7-h intervals for 5 d and composited by animal. Calcium intake increased (P < .05) with high-fat diets (195 vs 170 g/d), whereas Mg intake remained unchanged (54.3 +/- 9.0 g/d). Apparent absorption, estimated by Cr2O3, was regressed on Ca or Mg intake (grams/day) and fatty acid (FA) intake (grams/day). Total absorption of Ca (grams/day) = -37.4 + .264 Ca (P = .07, R2 = .14). Ruminal absorption of Mg was independent of FA intake, and magnesium was secreted posterior to the duodenum. Total tract Mg absorption (grams/day) was described by -7.685 + .464 Mg -.0044 FA (P < .0005, R2 = .46). Fat intake decreased (P < .05) total tract Mg absorption, and Ca absorption was decreased by high fat compared with low fat intake (P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)
Article
CaCO3 was added to a hay-grain ration already adequate in nutrients to determine the effect of doubling the Ca content of the ration on apparent digestibilities and serum levels of 11 minerals. Sixteen dairy cattle of two breeds (Holstein and Ayrshire) were randomly assigned to the control (0.7% Ca) or Ca-treatment (1.5% Ca) based on calving order. Each animal was fed to appetite for 80 days postpartum with no difference (P > 0.05) occurring between treatments in intake when expressed as a percentage of body weight. Five animals from each treatment were exposed to a 5-day digestibility trial. No change in organic matter apparent digestibility occurred but there were higher (P < 0.05) levels of Ca and Fe, increased (P < 0.01) levels of Cu, and lower (P < 0.05) Zn and Mo apparent digestibilities for animals on the Ca-treatment. Fecal pH was higher (P < 0.05) in the Ca-treated cows indicating a buffering action of the added CaCO3. In the serum, Ca and Zn concentrations were higher (P < 0.01), Cu increased (P < 0.05), and P was lower (P < 0.01) than the levels for the control animals. Breed effects were discernible as both P and Cu were higher (P < 0.01) in the serum of Ayrshires than of Holsteins. No change (P < 0.05) was evident in the secretion of minerals into the milk but urinary P concentration was higher (P < 0.05) in the control group. CaCO3 supplementation of the diet allowed the animals to go from a negative to a positive Ca balance (P < 0.01) and increased (P < 0.05) the amount of P apparent retention. In all, six essential minerals had altered apparent digestibilities and/or serum concentrations with possible long-term effects on animal metabolism. Key words: Calcium, mineral balance, digestibility, serum, dairy cattle
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Eight Morino lambs equipped with simple cannulac in the duodenum and terminal ileum were divided into two equal groups and used to study the net absorption of calcium, phosphorus and magnesium from concentrate diets supplemented by soyabean meal or by ensiled poultry litter. Mean net absorption of Ca, P and Mg for the soya-bean meal and poultry-litter treatments, respectively, was 31·6, 10·1; 34·7, 35·4; and 51·5, 41·6. Irrespective of the diet, the small intestino was the major site for Ca and P absorption and the stomachs for the absorption of Mg. A large secretion of P in the stomachs was found with both diets; 8·50 and 9·32 g/day for the soya-bean meal and poultry-litter treatments, respectively. The results of the present study support the view that poultry litter is a good source of P and Mg for sheep and can be used with deficient diets. Owing to the low rate of Ca absorption from the poultry-litter diet, it appears that at limited levels of inclusion, the extra added Ca would not be a detrimental factor.
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Dry matter disappearance and ruminal solubility of Ca, P, Mg, and K from samples of forages and diets containing these forages were measured. Forages included alfalfa hay (Medicago sativa L.), fescue hay (Festuca arundinacea Schreb.), bromegrass hay (Bromus inermis L.), and corn (Zea mays) silage. Diets were from lactating cow trials conducted by this laboratory and were formulated using the forages listed so that most of the dietary Ca would be supplied by forage. Mineral solubility and DM disappearance were measured in ruminally cannulated cows; nylon bags with samples were incubated for 0, 3, 12, 24, and 48 h. The 0-h bags were only washed with distilled water. For the 0-h samples, more than 60% of the P, Mg, and K in forages and diets was solubilized. However, 45% of the Ca in forages was soluble compared with 36% for diets. Magnesium solubility increased 22% with time for both forages and diets; otherwise, mineral solubilities at 3 h were not different from 0 h. Time for maximum solubility varied; K solubility was maximized by 0 h, Mg and P by 24 h, and Ca by 48 h. Across forages and diets, K was most soluble (99%) followed by Mg (92%), P (72%), and Ca (71%). Ruminal solubilities of K, Mg, and P were similar for forages and diets and averaged 93, 85, and 70%. respectively. Solubility of Ca from forages averaged 63% and was 12 percentage units greater than that of diets. These data indicate that rumen solubilization is not a factor limiting the ruminant's ability to absorb these macrominerals.
Article
Sheep cannulated in the rumen, duodenum and ileum were used to study absorption of minerals from diets: I. barley only (B), and II. 70% (DM basis) barley + 30% SO2 treated wheat straw (B+S). Na and K were highly absorbed from both diets and almost completely recovered in the urine. Ca apparent absorption was low: 12.1% and 13.4% in the B and B+S treatments, respectively. The Mg net absorption in the rumen was significantly higher in diet B than in diet B+S; the difference in total tract apparent absorption of Mg was, however, much smaller and not significant: 44.5% and 38.2% for the B and B+S treatments, respectively. Animal variation in P absorption was very large, ranging from 5% to 66%. There was a trend toward net secretion of Cu, Zn and Mn in the stomachs, the trend being 2–3 times higher in the B+S than B diet. Generally, the apparent absorption of Cu, Zn and Mn was lower in the B+S than B diet; however, the most notable difference was with Cu absorption.
Article
Eight young Merino rams fitted with T-shape cannulas in the duodenum and terminal ileum were allotted to two equal groups to study net absorption of cal- cium, phosphorus, and magnesium from concentrate diets supplemented by en- siled manure from caged layers or by soy- bean meal. Mean net absorption (percent of intake) of calcium, phosphorus, and magnesium from manure from caged layers and soybean meal diets were 1.94, 14.8; 55.4, 55.8; and 44.2, 35.0. Irrespective of diet, the small intestine was the major site for calcium and phos- phorus absorption and the rumen for absorption of magnesium. Secretion of phosphorus in rumen was 2.31 and 5.34 g/day for manure and soybean meal diets. Manure from caged layers supplies phosphorus and magnesium for sheep and can supplement deficient diets. Because of low calcium absorption from poultry manure, it appears that for Iimited inclu- sion, the extra calcium contributed by manure should not be detrimental.
Article
The estimates of the needs of cattle for macro-elements vary widely between the different committees, most variation being seen in the values for calcium and phosphorus and between those of United Kingdom Agricultural Research Council and other published systems. The main factors responsible are the values adopted for the absorbability of calcium in the diet and for the maintenance requirements of phosphorus. Agricultural Research Council have adopted a value of 0.68 to convert net into dietary calcium requirements. This value represents the maximum efficiency of absorption of dietary calcium and was derived from balance trials. Other systems have derived a figure based on values from radioactive studies which rarely exceed 0.45. Agricultural Research Council used a figure of 12 mg kg-1 liveweight day-1 for the minimum maintenance value of phosphorus. This value has subsequently been shown to apply only to situations where dietary P is absorbed with high efficiency (0.70-0.80). For other situations maintenance requirements increase as the absorbability of dietary P decreases. For instance, the maintenance requirements of adult cattle increases to 20 mg kg-1 liveweight day-1, a value close to those used by other systems. At present there is insufficient information on which to arrive at a scientifically based margin of safety to cover variation in the availability of macro-elements between diets and in the efficiency of absorption amongst animals.
Article
1. The changes in the solubility of calcium, magnesium and phosphorus in digesta flowing along the intestinal tract and the net movement across the intestinal wall of these elements were determined in six rams, each equipped with three T-shaped cannulas; cannulas were placed in a total of six different sites of the small intestine. Cr 2 O 3 was used as a marker substance to measure the rate of flow of the digesta. 2. The concentrations of soluble Ca, Mg and P decreased as digesta moved along the intestine. The greatest fall in soluble Ca occurred after the first 3 m of the intestine, while a significant decrease in soluble Mg was found only at 15 and 25 m from the pylorus. The concentration of soluble P in digesta decreased until the 7 m site and then remained stable. In the faeces, the level of soluble Mg was approximately 4 times higher than, and that of Ca equal to, the levels of Mg and Ca found in digesta flowing through the upper intestine. Unlike Ca and Mg, a very low concentration of soluble P was found in the faeces. 3. In the duodenum, 84, 78 and 62% of the total Ca, Mg and P respectively were soluble, whereas in the digesta flowing through the terminal ileum the corresponding values were 3·2, 7·2 and 19% for Ca, Mg and P respectively. 4. The forestomachs and the colon were found to be the main sites of Mg net absorption; 1·12 mmol/h was apparently absorbed from the stomach and 1·05 mmol/h from the colon. The upper small intestine (1–3 m from the pylorus) appeared to be the major site of Ca and P absorption. 5. In the last 10 m of the small intestine, considerable amounts of minerals were secreted; 4·70, 0·96 and 1·85 mmol Ca, Mg and P/h respectively were added to the digesta flowing between 15 and 25 m from the pylorus. The effect of the increase in the pH of digesta along the small intestine on the solubility of these minerals is discussed.
Article
Objectives were to determine the effect of dietary concentration of P in DM on routes of excretion of P and to evaluate direct and indirect measures of calculating DM digestibility and P excretion. Twelve lactating Holstein cows were fed 20 kg of DM containing .41% P daily for 4 wk and then were assigned randomly to one of three diets: low (.30%), medium (.41%), or high (.56%) in P for 9 wk. Total collections of excreta (feces and urine) and milk were made during wk 4, 7, 10, and 13. At wk 4, cows excreted 88.2% of P consumed daily: 68.6% of excreted P in feces, 1.0% in urine, and 30.3% secreted in milk. Cows assigned to the low P diet decreased intake by 26.8% and excretion of P in feces by 22.7% in wk 13 compared with wk 4, whereas cows fed the high P diet increased intake by 36.5% and excretion of P in feces by 48.6%. Digestibility of DM was 62.6% when calculated from total collection of feces but only 55.7 or 56.5% when estimated indirectly using Cr or acid detergent lignin as indigestible markers. Apparent excretion of P was less than that estimated using either of the marker techniques (49.7 vs. 59.1 and 58.1 +/- .7 g/d of P) because digestibility of DM was underestimated. A prediction equation was developed for P excretion based on P intake and milk production.
Article
There is a need to standardize the NDF procedure. Procedures have varied because of the use of different amylases in attempts to remove starch interference. The original Bacillus subtilis enzyme Type IIIA (XIA) no longer is available and has been replaced by a less effective enzyme. For fiber work, a new enzyme has received AOAC approval and is rapidly displacing other amylases in analytical work. This enzyme is available from Sigma (Number A3306; Sigma Chemical Co., St. Louis, MO). The original publications for NDF and ADF (43, 53) and the Agricultural Handbook 379 (14) are obsolete and of historical interest only. Up to date procedures should be followed. Triethylene glycol has replaced 2-ethoxyethanol because of reported toxicity. Considerable development in regard to fiber methods has occurred over the past 5 yr because of a redefinition of dietary fiber for man and monogastric animals that includes lignin and all polysaccharides resistant to mammalian digestive enzymes. In addition to NDF, new improved methods for total dietary fiber and nonstarch polysaccharides including pectin and beta-glucans now are available. The latter are also of interest in rumen fermentation. Unlike starch, their fermentations are like that of cellulose but faster and yield no lactic acid. Physical and biological properties of carbohydrate fractions are more important than their intrinsic composition.
Article
Sixteen male intact Holstein calves averaging 72 kg and 64 d of age were used to study the effects of high dietary Al on calf performance and P bioavailability. The main effects were two concentrations of added aluminum (0 and .20% Al) and two of added P (0 and .22% P). The basal diet contained, by analysis, .132% P, .74% Ca, and .021% Al. The calves were assigned to four treatment groups balanced according to body weight. The four treatments were 1) normal P, low Al; 2) low P, low Al; 3) low P, high Al; and 4) normal P, high Al. Calved had ad libitum access to their respective diets for 7 wk. Metabolism of a single oral 32P dose was determined during wk 6. The adverse effects of high dietary Al include a 17% reduction in feed intake and a 47% reduction in body weight gains. Alkaline phosphatase and plasma glutamic oxaloacetate transaminase activities increased in calves receiving the high Al diets. A negative balance of P and Ca was noted in the calves fed high concentrations of Al. Apparent absorption of 32P was reduced (37%) in calved fed diets high in Al (44% of dose vs. 69%). Urinary excretion of 32P was not affected by dietary Al concentrations. Calves fed the low P (deficient) diet showed significant reductions in feed intake, weight gain, serum inorganic P, bone ash, and P content of bone. Dietary P did not significantly affect 32P absorption. Adding .20% dietary Al severely affects P metabolism and performance of young growing calves.
Article
A crossover experimental design with an extra period was used with four lactating cows (645 kg BW) and two diets to measure the true absorption of Ca and P from alfalfa hay and corn silage. True absorption was calculated after dosing cows intravenously with 45Ca and 32P to measure endogenous fecal losses. In alfalfa hay and alfalfa-corn silage diets, the Ca and P that came from the hay or hay and silage fraction was 94 and 98% and 63 and 84%, respectively. Cows ate more DM (22.7 vs. 20.6 kg/d) and produced more FCM (35.2 vs. 32.0 kg/d) when consuming alfalfa-corn silage compared with alfalfa hay. True absorption of Ca from alfalfa-corn silage was greater (42.2%) than from alfalfa hay (24.6%). Partial true absorption of Ca from alfalfa hay was 23.5% and from corn silage 51.5%. True P absorption for total diet was similar for both alfalfa hay (64.4%) and alfalfa-corn silage (74.6%). Partial true absorption of P from alfalfa hay (67.3%) was different from that from corn silage (80.0%). Fecal endogenous Ca excretion was nearly double the value (31 vs. 16 mg/kg BW) currently used by NRC. True absorption of Ca from alfalfa was lower and from corn silage was higher than currently used in NRC feeding standards. True absorption of P was higher than values currently used by NRC.
Article
1. The rate of flow of digesta along the intestinal tract, and particularly the changes occurring in proteins during their passage through the intestine were determined in six rams; each animal was fistulated with three cannulas which involved six different sites of the intestine. Cr 2 O 3 was used as a marker substance to measure the rate of flow of the digesta. 2. In the sections of the intestine from 1 to 15 m posterior to the pylorus the amounts of water, dry matter and total nitrogen decreased gradually as a result of their absorption through the intestinal wall. The region of the intestine situated at a distance of 7–15 m from the pylorus was more active with respect to the absorption of N, whereas water and dry matter were adsorbed to a greater extent in the region from 1 to 7 m from the pylorus. 3. The only part of the intestine in which substantial increases of water, dry matter and total N were found was the section immediately distal to the pylorus, and these increases were caused by the inflow of bile, and pancreatic and duodenal juices. The net increase found beyond the entry of the common bile duct was 2.7 g protein N and 2.0 g non-protein N (NPN)/24 h. 4. The activities of trypsin, chymotrypsin and carboxypeptidase A and the ratio α-NH 2 NPN: protein N increased from the pylorus up to a distance of 7 m and decreased again from this point to a distance of 15 m from the pylorus. 5. In the sections of the intestine between 1 and 3 and between 3 and 7 m distant from the pylorus the extent of proteolysis exceeded considerably that of absorption of amino acids through the intestinal wall. This was concluded from the decrease in the rate of flow of protein amino acids (by 31% between 1 and 3 m distant from the pylorus and by 34% between 3 and 7 m) and the simultaneous increase in non-protein amino acids (by 20% in the region between 1 and 3 m) or no change in non-protein amino acids (between 3 and 7 m). 6. The relatively greater decrease in non-protein amino acids (by 57%) compared with that of protein amino acids (by 41%) occurring in the section 7 to 15 m distant from the pylorus showed that this is an area of most intensive absorption of amino acids. 7. In the lower section of the intestine, from 15 to 25 m distant from the pylorus, the total amount of amino acids showed almost no change; probably a net effect of loss and gain of amino acids mainly due to microbial activities. Increases in the dehydrogenase activity suggested enhancement of bacterial activity in this lower region of the intestine. 8. The supply of essential amino acids to the tissues of sheep is improved, compared with the amino acid composition of the diet, as the result of ruminal biosynthesis of essential amino acids and ruminal degradation of non-essential amino acids and preferential absorption of essential amino acids through the intestinal wall, particularly in the section of most intensive absorption, 7–15 m distant from the pylorus.
Article
Eleven nonlactating Holstein cows in late gestation were used to study the effect of dietary calcium concentration on apparent selenium absorption. Digestion trials with total collection helped to estimate apparent absorption of specific nutrients. Mean daily selenium intake ranged from 900 to 1700 micrograms per day. Regression analysis indicated apparent selenium absorption was maximum when dietary calcium was .8% of dry matter intake. Amounts of dietary calcium less or greater than .8% of dry matter intake reduced apparent selenium absorption. Dietary calcium quantitatively affected apparent selenium absorption in amounts of nutritional significance when selenium was provided from natural feedstuffs.
Article
The effect of dietary starch on the digestibility of total and cell wall (CW) monosaccharides of alfalfa hay, was examined in sheep equipped with rumen and duodenal cannulas. The experiment consisted of two treatments. In one of them the sheep received 803 g dry matter (DM) of alfalfa hay (A), and in the second, 242 g DM alfalfa hay + 553 g of a purified starchy concentrate mixture (A + conct ). Rumen volume was not significantly different between treatments, but the mean retention time of markers in the rumen was shorter, and their rate of passage was faster in the A treatment than in the A + conct treatment. The overall digestibility of total CWs and CW constituents was not depressed in the A + conct treatment, the values for total CW being: 58.2 and 58.9% for the A and A + conct treatments, respectively. However, the digestion of CW monosaccharides in the rumen of the A + conct sheep was reduced despite the 100% longer retention time of particles in the rumen. The complimentary digestion of the potentially digestible CW monosacharides has been completed in the hindgut. The digestibility of CW glucose was higher (72%) than that of xylose (57%) in both treatments. CW glucuronic acid was the least digestible constituent (40%). Soluble uronic acids, representing the pectic material, were highly digestible (86.5% in A), but this was reduced to 80.3 in the A + conct treatment.
Article
Objectives for this study were to determine the effect of energy supplementation on mineral release in and outflow from the rumen, independent of pH. Nonlactating Holstein cattle with ruminal cannulas were limit-fed chopped alfalfa hay with or without energy supplement. Treatments were 1) control, alfalfa plus ruminal infusion of 3 L/d of distilled water; 2) acid, alfalfa plus infusion of 3 L/d of 1N HCl; 3) energy supplement, alfalfa and ground corn plus infusion of 3 L/d of distilled water; and 4) buffered energy supplement, alfalfa, and ground corn plus infusion of 3 L/d of distilled water containing 90 g of NaHCO3. Macromineral intake was standardized across treatments by adjustment of infusion solutions with inorganic mineral sources. Dry matter consumed was 5 kg/d on treatments 1 and 2 and 8.4 kg/d on treatments 3 and 4. Mean ruminal pH was 6.8, 6.1, 5.6, and 6.2 for treatments 1 through 4, respectively. Ruminal pH was more significant than energy supplementation in dispersion of Ca, Mg, and P in ruminal digesta. Only 1, 17, and 27% of dietary K, Mg, and P flowed with solids from the rumen, but 52% of Ca and 41% of Cu remained with the solid phase.