<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>2007-1124</journal-id>
<journal-title><![CDATA[Revista mexicana de ciencias pecuarias]]></journal-title>
<abbrev-journal-title><![CDATA[Rev. mex. de cienc. pecuarias]]></abbrev-journal-title>
<issn>2007-1124</issn>
<publisher>
<publisher-name><![CDATA[Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S2007-11242015000400377</article-id>
<title-group>
<article-title xml:lang="es"><![CDATA[Balance regional de nitrógeno en el sistema de producción leche-forraje de la Comarca Lagunera, México]]></article-title>
<article-title xml:lang="en"><![CDATA[Regional nitrogen balance in the milk-forage production system in the Comarca Lagunera, Mexico]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Figueroa Viramontes]]></surname>
<given-names><![CDATA[Uriel]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Núñez Hernández]]></surname>
<given-names><![CDATA[Gregorio]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Reta Sánchez]]></surname>
<given-names><![CDATA[David Guadalupe]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Flores López]]></surname>
<given-names><![CDATA[Hugo Ernesto]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias Campo Experimental La Laguna ]]></institution>
<addr-line><![CDATA[Matamoros Coahuila]]></addr-line>
<country>México</country>
</aff>
<aff id="Af2">
<institution><![CDATA[,INIFAP Campo Experimental Centro Altos de Jalisco ]]></institution>
<addr-line><![CDATA[ ]]></addr-line>
<country>México</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>12</month>
<year>2015</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>12</month>
<year>2015</year>
</pub-date>
<volume>6</volume>
<numero>4</numero>
<fpage>377</fpage>
<lpage>392</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S2007-11242015000400377&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S2007-11242015000400377&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S2007-11242015000400377&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="es"><p><![CDATA[Resumen: El sistema intensivo de producción de leche en la Comarca Lagunera se caracteriza por grandes explotaciones con más de 1,000 vacas en lactancia y áreas para la producción de forrajes de riego. El presente estudio tuvo como objetivo estimar el balance entre el nitrógeno (N) del estiércol incorporado al suelo y el requerimiento de N por los cultivos forrajeros. Se revisaron estadísticas de la SAGARPA sobre el inventario ganadero y producción de forrajes de 1999 a 2011. La producción de estiércol y la excreción de N se estimaron en función de la producción diaria de leche, mientras que el requerimiento de N de los cultivos forrajeros se estimó en base al rendimiento y a la extracción de N por los cultivos. Los forrajes ocuparon el 69 % de la superficie de riego, con 89,500 ha. La producción de forraje fue de 1.2 millones t año-1 en materia seca (MS), mientras que el requerimiento de N fue de 15,070 t año-1. El inventario lechero fue de 423,000 vacas, con 53 % en lactancia. La producción de estiércol en MS fue de 842,000 t año-1, mientras que el N excretado fue de 44,154 t año-1. El balance regional expresado como [N incorporado - requerimiento de N por forrajes] fue de 187 kg ha-1, lo cual representa un exceso. Estudios previos muestran que un balance &lt;150 kg ha-1 permite una producción sustentable de leche. De acuerdo con los resultados del presente estudio, los municipios con una densidad mayor de 2.87 vacas ha-1 tendrán un balance &gt;150 kg ha-1.]]></p></abstract>
<abstract abstract-type="short" xml:lang="en"><p><![CDATA[Abstract: The intensive system of milk production in the Laguna Region is characterized by large farms with more than 1,000 milking cows and irrigated areas for forage production. The objective of this study was to estimate the balance between manure nitrogen (N) added to the soil and the requirement of N for forage crops. SAGARPA statistics were reviewed about dairy cows inventory and forage production during 1999-2011. Manure production and N excretion were estimated using daily milk production, while the crop N requirement was estimated based on crop yield and crop N removal. Forages occupied 69 % of the irrigated area, with 89,500 ha. Forage production was 1.2 million t yr-1 dry matter (DM), while the N requirement was 15,070 t yr-1. The dairy cow inventory was 423,000, with 53 % lactating. Manure production in DM was 842,000 t yr-1, while the N excreted was 44,154 t yr-1. The regional balance expressed as [N incorporated - crop N requirement] was 187 kg ha-1, which represents an excess. Previous studies showed that a balance &lt;150 kg ha-1 allows a sustainable milk production. According to the results of this study, municipalities with a cow density greater than 2.87 cows ha-1 will have a balance &gt;150 kg ha-1.]]></p></abstract>
<kwd-group>
<kwd lng="es"><![CDATA[Estiércol]]></kwd>
<kwd lng="es"><![CDATA[Densidad de vacas]]></kwd>
<kwd lng="es"><![CDATA[Balance de Nitrógeno.]]></kwd>
<kwd lng="en"><![CDATA[Manure]]></kwd>
<kwd lng="en"><![CDATA[Cow density]]></kwd>
<kwd lng="en"><![CDATA[N efficiency]]></kwd>
<kwd lng="en"><![CDATA[N excretion]]></kwd>
<kwd lng="en"><![CDATA[Crop N extraction]]></kwd>
</kwd-group>
</article-meta>
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