This study evaluated the effect of nutritional supplementation and socio-sexual cues upon reproductive efficiency of goats exposed to the male effect under rangeland grazing conditions (22°N). Criollo goats (n = 73) were distributed in four experimental groups: (1) continuous males (CM, n = 19) in which males (n = 2) remained together with females from 7 March to 28 July; (2) supplemented males (SM, n = 16) in which males (n = 2) were kept separately and were individually supplemented with 18% crude protein and 2.77 Mcal ME kg–1 DM, during a 30-day period; (3) supplemented males exposed to the female effect (SM + FE, n = 19), in which supplemented males (n = 2) were maintained with females induced to oestrus before being used for male effect; and (4) supplemented males and supplemented females (SM + SF, n = 19) in which males (n = 2) were supplemented as in group SM, and females received the same supplementation as males 30 days before and 30 days after male introduction. Grazing was performed from 0900 to 1900 hours; liveweight (LW) was registered weekly before grazing and (or) supplementation. Ovarian activity was evaluated (serum P4 concentrations) in the four groups before and after male introduction. At the beginning of the study and supplementation, female LW did not differ among treatments (P > 0.01). However, during the supplementation phase, LW increased in a different fashion among groups (P < 0.002), favouring the SM, SM + FE and SM + SF groups. A positive correlation between female LW at the beginning of the rainy season and the onset of ovulatory activity was observed (r = +0.90; P < 0.01). The average date for the onset of ovarian activity differed (P < 0.001) among groups, being earlier in the SM + SF group (9 May ± 4.3 days), which also depicted the shortest interval between the introduction of males until the onset of ovulatory activity (P < 0.001). Results of the present study indicate that nutritional signalling of the reproductive activity of both female and male Criollo goats reared under marginal conditions surmounts the inhibitory effects of long-day photoperiods during the non-reproductive season. An increased level of nutrition during the anestrous season may be used to increase reproductive function of both male and female goats reared in harsh nutritional conditions and applied as a green, clean, and ethical reproductive tool at these latitudes.

RESUMENLa cabra se localiza en agroecosistemas frágiles. Con el propósito de evaluar el efecto de tecnologías aplicadas de manera participativa, en un marco de conservación de los recursos naturales sobre la productividad de pequeños rumiantes, se probaron seis tecnologías: 1) El pastoreo diferido rotacional (SPDR) logró 60 % de cubierta vegetal y 35 % pastoreo continuo (PAC); 996.5 vs. 280.8 kg·ha -1 de materia seca (P<0.01) y composición botánica de 59 especies vs. 27 en SPRD y PAC, respectivamente; 2) De 200 presas filtrantes construidas, hubo retenciones hasta de 212 t de suelo sedimentado en presas de 25.5 m de ancho; 3) Resiembras con nopal Amarilla Olorosa tuvieron una supervivencia de 90.7 %; 4) La siembra de cebada logró rendimientos (MS) similares al maíz con mayor proteína cruda; 5) La suplementación de cabras y cabritos (0-5 meses) con bloques nutricionales, incrementó el PV (P<0.001) en cabritos de parto doble (71.9 g·día -1 ), respecto a cabritos dobles (46.5 g·día -1 ) y cabritos sencillos (40.7 g·día -1 ) no suplementados; 6) Quesos de leche caprina y bovina no difirieron (P<0.05) en atributos valorados, logrando la participación de mujeres. El enfoque de sistemas participativos permitió diseñar actividades apropiadas, incrementando la productividad y promoviendo la conservación de recursos naturales. ABSTRACTThe goat is located in fragile ecosystems. In order to evaluate the effect of applied technologies in a participatory manner, within a framework of conservation of natural resources, on the productivity of small ruminants, six technologies were tested: 1) deferred-rotation grazing system (DRGS) achieved 60 % vegetation cover compared to 35 % for continuous grazing (CG); 996.5 vs. 280.8 kg . ha -1 of dry matter (P<0.01) and botanical composition of 59 species vs. 27 in DRGS and CG, respectively; 2) of 200 filter dams built, up to 212 t of soil sediment was captured in 25.5-m-wide dams; 3) reseeding with Amarilla Olorosa (fragrant yellow) prickly pear cactus had a 90.7 % survival rate; 4) sowing of barley achieved yields (MS) similar to corn but with higher crude protein; 5) supplementation of goat does and kids (0-5 months) with nutritional blocks increased live weight (P<0.001) in double birth kids (71.9 g . day -1 ) compared to unsupplemented double and single kids (46.5 g . day -1 and 40.7 g . day -1 , respectively); 6) goat and cow's milk cheeses did not differ (P<0.05) in measured attributes, achieving the participation of women. The participatory systems approach enabled designing appropriate activities, increasing productivity and promoting conservation of natural resources. PALABRAS CLAVE:Sistemas de producción, investigación participativa, tecnología, género. KEY WORDS:Production systems, participatory research, technology, gende INTRODUCCIÓNEl concepto de sistema permite comprender fenómenos complejos de componentes físicos, que actúan como una unidad y dan como resultado un proceso o producto bien caracterizado. Los sistemas incluyen factores diversos de clima y suelo, por lo que e...

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