ABSTRACT.- This study investigated two outbreaks of spontaneous poisoning by Baccharis coridifolia (Asteraceae) in early-weaned beef calves in Tacuarembó, Uruguay. A total of 34 affected calves showed signs of salivation, anorexia, apathy, marked dehydration, and diarrhea. Deaths occurred 36-72 h after consumption and mortality varied from 37.5% to 43.3% for outbreak 1 and outbreak 2, respectively. The main pathological findings include diffuse severe necrosis of the prestomachs and lymphoid tissues.

ABSTRACT.- This study investigated two outbreaks of spontaneous poisoning by Baccharis coridifolia (Asteraceae) in early-weaned beef calves in Tacuarembó, Uruguay. A total of 34 affected calves showed signs of salivation, anorexia, apathy, marked dehydration, and diarrhea. Deaths occurred 36-72 h after consumption and mortality varied from 37.5% to 43.3% for outbreak 1 and outbreak 2, respectively. The main pathological findings include diffuse severe necrosis of the prestomachs and lymphoid tissues.

Pasture response to N fertilization and the nitrogen use efficiency (NUE) is highly conditioned by the phosphorus (P) availability and soil water. The objective of the study was to evaluate the effect of NP fertilization on the NUE of annual ryegrass, in two growth periods.

Nutrients deficiencies - mainly phosphorus (P) and nitrogen (N) - often depress forage productivity (FP) in pasture-based systems in the Pampas region (Argentina). Fertilizations are often used to attenuate these deficiencies, but it is necessary to increase the use efficiency of the applied nutrients.

ABSTRACT.- Feed and energy efficiency have been topics of extensive research in recent years, with residual feed intake (RFI) being the preferred index to determine feed efficiency in beef cattle. Nevertheless, the biggest downside of RFI is that its measurement requires accurately determining individual feed intake, which leads to the need to carry out RFI trials in confinement conditions.