Sixteen intact male Holstein calves averaging 86 kg and 63 d of age were assigned randomly to four treatment groups. The four treatment diets contained .17, .67, 1.31, and 2.35% Ca on an as-fed basis. The resulting Ca:P ratios with P held constant at about .34% were .47:1, 1.92:1, 3.83:1, and 7.20:1. Calves were fed diets at 3% of their body weights for 4 wk. Magnesium in the bone ash and serum was lowered by the 2.35% Ca treatment. Serum inorganic P was also reduced by the highest Ca diet during the last 2 wk of the experiment. Liver had the highest concentration of Zn in calves fed .67% Ca, and the muscle from calves fed 1.31% Ca diet had the lowest amount of Zn. Copper was reduced in pancreas for 1.31% Ca diet, but Ca was highest in the muscle and heart at the .67% Ca treatment. Weight gains and feed efficiencies were not affected by Ca. Fecal pH was different among treatments and increased as Ca intake increased. Young growing dairy calves can adapt to a wide range of Ca intakes and Ca:P ratios and maintain a moderate growth rate for 4 wk. It appears that excessive dietary Ca may affect concentrations of Zn, Fe, Cu, and Mn in some body tissues, but the magnitude of the effect is relatively small.

Influence of dietary Ca on Se metabolism was studied with 16 intact male Holstein calves averaging 86 kg. Calves were assigned randomly and fed one of four diets containing, .17, .67, 1.31, and 2.35% Ca at 3% of their body weight for 4 wk. The diets contained .062 ppm Se and .34% P. Four days prior to the end of the experiment, calves were dosed orally with radioactive 75Se. Dietary Ca had no significant effect on 75Se absorption. There was a slight curvilinear relationship between apparent 75Se absorption and dietary Ca intakes. Urinary excretion of 75Se and stable Se tended to decrease with increasing dietary Ca, but differences were not significant. No significant differences were found in concentration of 75Se in several tissues. Kidney and liver had the highest concentration with that in kidney being about four times that of liver. Apparent 75Se absorption was decreased 10 to 6%, respectively, in calves fed extremely low and high amounts of Ca, compared with those receiving the requirement (.67% Ca). These small reductions along with a small R2 suggest that dietary Ca probably is of little practical importance relative to Se metabolism in calves.

Metabolism of orally dosed 75Se was studied in 10 intact male Holstein calves that were fed ad libitum a control diet containing no added Pb or supplemented with 1000 ppm Pb as PbSO4 for 4 wk. Lead-supplemented calves did not exhibit any clinical signs of Pb toxicity. Voluntary feed intake was reduced by 9.5% and average daily gain by 23%. Lead content of rib, liver, and kidney increased. Serum glutamic oxaloacetate transaminase activity was increased during the last 2 wk of the experiment in calves fed Pb. In calves receiving supplemental Pb, 75Se absorption, blood concentration, and urine concentration were reduced by 26, 21, and 42%, respectively. Tissue 75Se concentrations were significantly lower in kidney, liver, testicle, pancreas, small intestine, heart, spinal cord, and muscle in calves fed Pb. There was a significant negative correlation (r = -.78) between 75Se and stable Pb concentrations in the liver. It is not clear whether the ingestion of subclinical amounts of Pb could affect the absorption and utilization of Se in dairy calves to the extent of Se deficiency when dairy calves are kept in areas known to be low in Se.

RESUMENLa utilización de taninos condensados de quebracho (TCQ) puede resultar beneficiosa, inocua o perjudicial en el comportamiento productivo de los rumiantes. El objetivo del presente trabajo fue el de evaluar los efectos de la inclusión de TCQ al 2% del consumo estimado de materia seca (CMS) en la dieta de cabras lecheras sobre el consumo, la producción y la composición de leche. Se emplearon 16 cabras Saanen en inicio de lactancia. El periodo experimental fue de 11 semanas. Los tratamientos fueron: sin suministro de taninos condensados de quebracho (STQ) y con suministro (CTQ). El diseño experimental fue un diseño completamente al azar con mediciones repetidas en el tiempo. El análisis estadístico de los datos se realizó a través del programa InfoStat versión 2017p. No se registraron diferencias estadísticamente significativas para ninguno de los parámetros productivos considerados. Por lo que es posible concluir que la inclusión de TCQ en las condiciones y dosis empleada no reportó beneficio alguno en los parámetros evaluados. ABSTRACT Effects of condensed tannins of Schinopsis balansae in dairy goat's productive performance.The inclusion of quebracho condensed tannins (TCQ) can be beneficial, innocuous or harmful in ruminant's productive performance. The aim of these work was to evaluate the effects on intake, milk production and composition of TCQ inclusion in dairy goat's diet at a concentration of 2% of estimated dry matter intake (CMS). Sixteen Saanen goats in early lactation were used. The ex- EFECTOS DE TANINOS CONDENSADOS DESchinopsis balansae EN LA DIETA DE CABRAS LECHERAS SOBRE PARÁMETROS PRODUCTIVOS e-ISSN 2346-9129 Martínez, G. M.; Suárez, V. H.; Olmos, L. H.; Alfaro, R. J.; Alfaro, E. J.; Yanes, R. P. & Orosco, S. M. Efectos de taninos condensados de Schinopsis balansae en la dieta de cabras lecheras sobre parámetros productivos.perimental period was 11 weeks. The treatments were: no supply of quebracho condensed tannins (STQ) and with supply (CTQ). The experimental design was a completely randomized design with measurements repeated over time. Infostat program, 2017p has been used to carry out the statistical analysis. No statistically significant differences were registered for any of the productive parameters considered. So it is possible to conclude that TCQ inclusion in the conditions and dose used did not report any benefit in the parameters evaluated).

El objetivo del presente trabajo fue evaluar el desempeño productivo y desarrollo ruminal de cabritos Saanen alimentados con alfalfa y/o grano (Alf, Alf + Gr, Gr) y faenados a distintas edades (50, 60 y 70 días). Se evaluó: ganancia diaria de peso vivo (GDPV), peso a faena (PF), peso de la canal caliente (PCC), rendimiento a faena (RF),  peso de los estómagos y el largo de las pailas (LP). El diseño fue DCA con arreglo factorial y para la comparación de medias se utilizó LSD (p=0,05). Los animales fueron asignados al azar dentro de los tratamientos: Alf 50 (n=3), Alf 60 (n=4), Alf 70 (n=3), Gr 50 (n=3), Gr 60 (n=4), Gr 70 (n=3), Alf+Gr 50 (n=3), Alf+Gr 60 (n=4), Alf+Gr 70 (n=3).  Los datos fueron analizados mediante ANOVA de Infostat 2018. No se detectó interacción entre dieta y edad de faena para ninguno de los parámetros. En cuanto a la dieta, los animales que consumieron Alf y Alf + Gr presentaron mayores GDPV (p= 0,0022). El PF fue superior para el grupo Alf+Gr respecto al Gr (p=0,0352). Similar fue lo relevado para el PCC (p=0,0298). El RF fue mayor para el grupo Gr respecto a las otras dietas (p <0,0001). La edad a faena impactó en el PF y PCC resultando superior en los animales faenados con 70 días, (p= 0,0002 y p= 0,0008 respectivamente), mientras que aquellos sacrificados a los 50 días presentaron el mayor RF (p=0,0413). El peso del rumen fue superior para el grupo 70  vs. 50 y 60 días (p=0,0410). El LP fue similar para todos los tratamientos. Se puede concluir que para las condiciones del presente ensayo tanto la dieta suministrada como la edad a faena afectaron el desempeño productivo de los animales.