Animal energetics in extensive grazing systems: Rationality and results of research models to improve energy efficiency of beef cow-calf grazing Campos systems1

Grazing management for more resilient mixed livestock farming systems on native grasslands of southern South America

“…By integrating these two levels, it should be underlined that sheep alone are not “the problem”, but rather that low forage allowance and high sheep‐to‐cow ratios seem directly related to low levels of farm productivity under drought conditions. This is expressed by forage allowance at paddock level and not by stocking rate, as was previously found by Do Carmo et al (), Do Carmo et al () and discussed by Sollenberger et al (). While stocking rate is a relevant metric for explaining farm performance, forage allowance (kg grass dry matter per kg animal body weight) is the key variable for grassland management.…”

“…Cow pregnancy rate was affected by the drought because lower herbage growth and supply caused weight loss of the animals. The drought particularly affected cow–calf systems since it occurred during the mating season (December–February), when the nutritional status of the cows strongly determines the pregnancy rate (Do Carmo et al, ; Soca & Orcasberro, ). Farm meat productivity is a direct function of pregnancy rate, since the most important product of these farms are calves, and lower pregnancy rates mean fewer calves, less livestock to market and lower meat productivity (Paparamborda, ).…”

“…Higher herbage allowance corresponds with a taller sward. This, typically, will have greater species diversity (Carvalho et al, ; Overbeck, Müller, Pillar, & Pfadenhauer, ; Soca et al, ) and can be achieved through stocking rate management (Do Carmo, Claramunt, Carriquiry, & Soca, ; Sollenberger, ). Higher levels of aboveground biomass are related to deeper and denser rooting systems, and these improve the resilience of grasslands to droughts (Bartaburu, Duarte, Montes, Morales Grosskopf, & Pereira, ; Norton, Malinowski, & Volaire, ; Van Ruijven & Berendse, ).…”

Mobilizing Ecological Processes for Herbivore Production: Farmers and Researchers Learning Together

“…In this second farm, precipitation during springsummer had a huge effect on herbage yield. The stocking rate in HHA was lower, but the cow pregnancy rate (88 vs. 59%), calf weaning weight (194 vs. 175 kg;Claramunt et al, 2017), production per unit area, and production efficiency (g calf/MJ energy consumed per cow and per year) were higher in HHA than in LHA (Do Carmo et al, 2016). High HA led to moderate improvements in cow BCS (0.5 units) and energy intake (11%) during autumn.…”

“…Decreasing the stocking rate leads to a higher herbage allowance from calving in spring to calf weaning in autumn (Soca and Orcasberro, 1992; Figure 3), which is likely to rapidly increase BCS after calving and thus shorten cow PPA and improve the pregnancy rate. This is also assumed to benefit calf weight at weaning, meat production per ha, farm economic outputs, and ecosystem services due to a better soil cover and higher sward structural heterogeneity (Do Carmo et al, 2016).…”