The Brazilian territory contains approximately 160 million hectares of pastures, and it is necessary to develop techniques to automate their management and increase their production. This technical note has two objectives: First, to estimate the canopy height using unmanned aerial vehicle (UAV) photogrammetry; second, to propose an equation for the estimation of biomass of Brazilian savanna (Cerrado) pastures based on UAV canopy height. Four experimental units of Panicum maximum cv. BRS Tamani were evaluated. Herbage mass sampling, height measurements, and UAV image collection were simultaneously performed. The UAVs were flown at a height of 50 m, and images were generated with a mean ground sample distance (GSD) of approximately 1.55 cm. The forage canopy height estimated by UAVs was calculated as the difference between the digital surface model (DSM) and the digital terrain model (DTM). The R² between ruler height and UAV height was 0.80; between biomass (kg ha⁻¹ GB—green biomass) and ruler height, 0.81; and between biomass (kg ha⁻¹ GB) and UAV height, 0.74. UAV photogrammetry proved to be a potential technique to estimate height and biomass in Brazilian Panicum maximum cv. BRS Tamani pastures located in the endangered Brazilian savanna (Cerrado) biome.

The objective of this study was to evaluate pregnancy rates of recipients of different breed groups (Nellore and crossbreed), as well as the effects of size and type of the corpus luteum (CL) on plasmatic concentrations of progesterone and pregnancy rates of embryo recipients. A total of 152 heifers were synchronized with progesterone implants and on the day of embryo transfer, previously obtained by superovulation and frozen in ethylene glycol, the diameter and type of the corpus luteum (cavitary and compact) was measured and blood was collected for progesterone measurement. The pregnancy rate was 44.1%, with a diameter of corpus luteum higher in recipients that became pregnant (2.03±0.41) compared with non-pregnant ones (1.86±0.34 cm). Plasmatic concentrations of progesterone did not differ between pregnant (1.50±1.05) and non-pregnant (1.31±0.91 ng/mL) animals. The type of corpus luteum did not influence the pregnancy rates. Only Angus and crossbred Marchigiana differ among themselves in pregnancy rates (33.3 and 59.2%, respectively). The pregnancy probability was affected only by CL diameter, but not by P4 plasmatic concentration. Selection of the corpus luteum size at the time of embryo transfer is an important factor to increase pregnancy rates in recipients, and compact and cavitary corpora lutea do not influence the pregnancy rates of bovine embryo recipients. Nellore recipients have pregnancy rates that are satisfactory and comparable to crossbred (Bos taurus × Bos indicus) recipients

The objectives of the present study were to estimate dry-matter intake and output of faeces using two external and four internal markers in sheep fed Brachiaria brizantha cv. Marandu on an ad libitum basis over 3- and 5-day periods. Six sheep fitted with ruminal cannulas were randomly assigned in a crossover design experiment to receive either of two treatments of external markers, namely titanium dioxide (TiO2) and chromic oxide (Cr2O3). Faecal output was obtained by total faecal collection and faecal grab sampling. Faeces were collected for 3- or 5-day periods, and, for each collection period, two sampling methods were compared; grab samples were collected directly in the rectum once daily, and a second sample was taken at the same time directly in faecal collection bags after having determined the daily total output of faeces. Faecal concentrations of the internal markers, indigestible dry matter, indigestible neutral detergent fibre, indigestible acid detergent fibre and indigestible acid detergent lignin (iADL), were determined. Faecal output was not accurately predicted with indigestible dry matter, indigestible neutral detergent fibre, indigestible acid detergent fibre and iADL. Dry-matter intake was predicted with iADL and TiO2 when faeces were collected for 5 days as grab samples once daily, or as total collection and with Cr2O3 when faecal grab samples were collected for 5 days. The results using external markers indicated that TiO2 is not a marker equivalent to Cr2O3 for estimating intake and faecal output. TiO2 was the only external marker to accurately estimate faecal output, independent of the method (total or grab) and time period (3 or 5 days) used; this suggests that TiO2 is the best marker tested for predicting the faecal output of sheep that are fed a diet of fresh Brachiaria brizantha (cv. Marandu) grass ad libitum.