Relevance of farm-scale indicators and tools for farmers to assess sustainability of their mixed crop-ruminant livestock systems.

Ensuring the sustainability and circularity of mixed crop-ruminant livestock systems is essential if they are to deliver on the enhancement of long-term productivity and profitability with a smaller footprint. The objectives of this study were to select indicators in the environmental, economic and social dimensions of sustainability of crop-livestock systems, to assess if these indicators are relevant in the operational schedule of farmers, and to score the indicators in these farm systems. The scoring system was based on relevance to farmers, data availability, frequency of use, and policy. The study was successful in the assemblage of a suite of indicators comprising three dimensions of sustainability and the development of criteria to assess the usefulness of these indicators in crop-ruminant livestock systems in distinct agro-climatic regions across the globe. Except for ammonia emissions, indicators within the Emissions to air theme obtained high scores, as expected from mixed crop-ruminant systems in countries transitioning towards low emission production systems. Despite the inherent association between nutrient losses and water quality, the sum of scores was numerically greater for the former, attributed to a mix of economic and policy incentives. The sum of indicator scores within the Profitability theme (farm net income, expenditure and revenue) received the highest scores in the economic dimension. The Workforce theme (diversity, education, succession) stood out within the social dimension, reflecting the need for an engaged labor force that requires knowledge and skills in both crop and livestock husbandry. The development of surveys with farmers/stakeholders to assess the relevance of farm-scale indicators and tools is important to support direct actions and policies in support of sustainable mixed crop-ruminant livestock farm systems.

Effects of monensin in supplements for beef cattle in tropical grazing systems during the rainy season.

Two experiments were carried out to evaluate the effect of monensin in supplements for grazing heifers. In experiment I, treatments consisted of protein supplements (low intake - 0.5 kg/animal/day and high intake - 1.0 kg/animal/day) associated or not with monensin. Animal performance, nutrient intake, and digestibility were evaluated. Forty crossbred heifers with an initial body weight (BW) of 213.8 ± 4.5 kg were used. There was no difference in average daily gain between treatments (average of 0.588 kg/animal/day). There was no interaction between monensin and supplements for intake parameters and digestibility. Dry matter (DM) intake was equal between treatments (~ 2% of BW). However, there was a reduction in pasture intake with the high-intake supplement. In experiment II, treatments consisted of two types of supplements (protein or mineral) associated or not with monensin. The variables analyzed were productive performance, ingestive behavior, and thermal comfort, evaluated through the index of thermal stress for cows (ITSC). Forty crossbred heifers with a BW of 159.2 ± 1.3 kg were used. The type of supplement did not influence the performance of the animals. However, monensin promoted greater weight gain in the animals (110 g/animal/day). There was an interaction effect between supplementation and monensin addition on behavioral activities, except for idle time. The inclusion of monensin in the protein supplement reduced the grazing time. The ITSC value influenced the activities of ingestive behavior, and the increase of this index reduced the grazing time in all treatments. Forage quality influences the response to monensin use, and the addition of monensin in supplements for grazing cattle during the rainy season is recommended for forages with high CP content.