The effects of two innovative feeding strategies-intensive grazing (GR) and maize silage (MS)-on the sustainability of small-scale dairy systems (SSDS) were assessed in the highlands of central Mexico. On a total of 24 farms, four innovations were adopted between 2011 and 2014. Five farms continued their conventional feeding strategy (CC) of cut-and-carry pasture supplemented with commercial concentrate and ground corn grain, as well as straws (maize, oat, and wheat) in the dry season of feed scarcity; six farms implemented MS in the dry season; six farms GR of pastures; and seven farms implemented both GR and MS. Assessment in 2015 showed that farms which implemented both GR and MS had a higher local diversity score (P ≤ 0.001), higher scores for ethics and human development, and a higher score in economic independence (P ≤ 0.05) than farms that implemented only one of the innovations. The overall sustainability score (with range 0-100) was 46 for CC, 47 for MS, 52 for GR, and 55 for GR + MS. The innovations reduced feeding costs and enhanced sustainability, particularly when GR + MS were both implemented.

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<p>The cattle raising is mainly developed in pastures and secondary forest (named: acahuales) in Campeche, and recently silvopastoral systems have been also fostered in this region. These grazing systems were evaluated to determine their role to reduce greenhouse gas emissions (eGEI) in tropical livestock systems. The study was carried out using a “door to door” life-cycle assessment (LCA) of cow-calve (UPPc) and dual-purpose (UPPdp) units. The functional unit was one kilogram of live weight adjusted for protein content (kgPV-eq). The eGEI were not different among grazing systems due to their similarities in productivity and the origin of dry matter in diet. However, when eGEI of the UPPc and UPPdp were compared, these were different (P &lt;0.01), due to productivity per hectare of UPPdp was greater than the UPPc. Something similar occurred for land use, where the UPPdp needed less area than the UPPc, since milk almost twofold the total functional unit production. In this study, productivity had a great influence on the reduction of eGEI, but the grazing system did not make difference. The LCA was useful to objectively evaluate the livestock systems in Campeche and detect key points on eGEI reduction and farm productivity.</p>

<p><strong>Background:</strong> Nitrogen (N) plays an important role within milk production systems (MPS), as an indicator of environmental and economic efficiency. <strong>Objective. </strong>The objective was to determine utilisation of N offered in the ration and estimate GHG from the enteric fermentation and manure management in 12 small-scale dairy farms under two feeding strategies. <strong>Methodology.</strong> Six farms had their herds in confinement under a cut-and-carry feeding system, and six farms implemented day grazing of mixed pastures, both systems used commercial concentrates as a supplement. Cows in milk production and their replacements were considered in the study. Pasture intake was calculated by difference in dry matter intake, using 3.2 % of live weight as intake factor. The N utilisation was determined by difference between N intake and excretion at each farm during a whole year operation. The GHG emissions were estimated following Tier 2 guidelines rom IPCC. Differences in feeding strategies were analysed with a completely random block design using farms as a blocking factor. <strong>Results.</strong> Mean farm size was 5.0 ha for cut-and-carry and 16.0 ha for grazing, and dry matter feed self-sufficiency was 62 and 83% respectively, considering 12% and 22% refusals for each strategy. There were no statistically significant differences (P&gt;0.05) for any of the N utilisation components (N in diet, N in milk, N in manure, NH₃ and N₂O or GHG emissions. <strong>Implications.</strong> This is a novel report on assessing N fluxes and GHG emissions from small-scale dairy systems in Mexico and Latin America. <strong>Conclusions.</strong> In general, 87.6% of the N consumed is excreted in manure and urine. The feeding strategies did not diverge enough to have an impact on GHG emissions.</p>