Crossbreeding has been used to improve performance in beef cattle, however the effects of breed composition on methane (CH 4 ) production, yield and intensity from cattle raised in tropical intensive and integrated systems remain unknown. To assess the impact of breed composition on performance and methane emissions, Nellore (NEL; yr 1: BW = 171.5 ± 19.4 kg; n = 10; yr 2: BW = 215.8 ± 32.3 kg, n = 25) and Angus x Nellore crossbred (AN; yr 1: BW = 214.2 ± 26.4 kg, n = 10; yr 2: BW = 242.5 ± 32.2 kg, n = 25) were compared. The animals grazed on integrated crop-livestock system in the growing phase (stocking rate 2452 kg BW/ha, herbage mass 4,884 kg dry matter (DM)/ha, forage allowance 5.9 kg DM/100kg BW) and then were finished in a feedlot. Steers (n = 8) from each breed composition were randomly selected in each phase to measure CH 4 production using a sulfur hexafluoride (SF 6 ) tracer technique and DM intake (DMI) using titanium dioxide. Compared with NEL, AN had both superior total gain and average daily gain (ADG) in the grazing period. The AN presented greater ADG in the feedlot with a shorter finishing period and resulted in greater carcass yield and carcass ADG. Methane production (kg/period) was lower in NEL (19% less) than AN in grazing ( P <0.01), and no difference was observed in feedlot. The NEL had less CH 4 intensity (CH 4 /BW) in grazing but greater CH 4 per unit of ADG in the feedlot compared to AN. Breed composition did not influence the CH 4 yield (CH 4 /DMI) in either phase, despite the difference in feedlot DMI (kg/day). In conclusion, crossbreeding may be an option to improve performance and reduce the CH 4 per ADG in tropical climate conditions, resulting in lower methane emission per kg of meat produced.

A pitiose eqüina, causada pelo Pythium insidiosum, pode formar lesões profundas, de difícil tratamento que, freqüentemente, culminam na morte dos animais. O quadro agudo da doença pode ser confundido com habronemose cutânea ou outras dermatoses em eqüinos. Neste relato é descrito um quadro fatal de pitiose eqüina no Norte de Minas Gerais, Brasil, em que o animal foi inicialmente tratado para habronemose. Uma égua Mangalarga Marchador, de alto valor econômico e gestante, apresentou uma ferida na região inguinal do membro posterior direito. A lesão, com bordas elevadas e consistentes, possuía 20x35 cm de diâmetro, e envolvia vasos sanguíneos calibrosos. Após diagnóstico clínico de pitiose, foram instituídas a imunoterapia e a assepsia local com solução de iodo. Quatro meses após o início dessa terapia, a ferida apresentou melhora clínica, no entanto, o animal emagreceu, abortou e, posteriormente, foi a óbito. A única alteração visível à necropsia foi a lesão cutânea com aproximadamente 20 cm de diâmetro, profunda, chegando próxima ao osso fêmur. Ao ser dissecada, esta revelou a presença de inúmeros "kunkers" mergulhados em exsudato fétido e limitados por uma cápsula fibrosa. O exame micológico com KOH e o cultivo de fragmentos desses "kunkers" revelaram a presença de hifas hialinas espessas, sugestivas do gênero Pythium. A ocorrência de pitiose eqüina deve ser considerada mesmo em regiões semi-áridas, como o Norte de Minas, e o diagnóstico tardio da doença pode ter comprometido a eficácia da imunoterapia, proporcionando maior contaminação secundária e culminando na morte do animal.Descritores: pitiose, diagnóstico diferencial, imunoterapia, norte de Minas Gerais, eqüinos. ABSTRACTThe equine pythiosis, caused by the Pythium insidiosum can produce subcutaneous lesions with difficult treatment and frequently it results in the animal death. The initial curse can be early diagnosticed to cutaneous habronemiasis or other equine dermatosis. This report analysed a fatal case of equine pythiosis in the north of Minas Gerais, Brazil, in that the animal was initially treated to habronemiasis. One Mangalarga Marchador mare of high value pedigree and with two months of gestation showed an inguinal lesion in the hind limb. The cutaneous illness was characterized by large (20x35 cm of diameter), circumscribed tumorous masses and it evolved large sanguineous vases. After six months of the initial skin injures and of the treatment to habronemiasis, it was clinically diagnosticed the pythiosis and instituted the immunotherapy and local asepsis with iodine solutions. The lesion reduced significantly, however the animal had reduction of corporal score, aborted and died after four months with this therapy. The visible alteration at necropsy exam was the cutaneous lesion with 10x15 cm of diameter, infiltrating near the femur. The analysis of this lesion showed the presence of innumerous "kunkers" dipped in a fetid secretion and evolved by a fibrous capsule. The direct test with KOH and the culture exams showed the presence of large and ...

-The objective of this work was to evaluate the performance of crossbred steers post-weaned in an integrated crop-livestock system (ICL) and finished in a feedlot, fed either a high-level concentrate diet or whole corn with no roughage. Weaned calves of two breed groups -½ Angus × ½ Nellore, and ½ Charolais × ¼ Angus × ¼ Nellore -were allotted in a completely randomized experimental design (CRD). During the rainy season, the ½ Angus × ½ Nellore animals showed a higher performance than the ½ Charolais × ¼ Angus ×¼ Nellore ones, with 0.748 and 0.490 kg average daily gain, respectively. The productivity in the post-weaning period was 926 kg ha -1 body weight in a 11-month period, in the ICL system. Subsequently, the animals were confined and fed high-concentrate diet or whole corn with no roughage, in a CRD with a 2×2 factorial arrangement. In the feedlot, the ½ Charolais × ¼ Angus × ¼ Nellore animals showed lower values for carcass average daily gain, carcass yield, and slaughter weight than the ½ Angus × ½ Nellore animals. The high productivity in the ICL shows that this strategy, associated with the use of crossbreeding during the post-weaning and finishing stages, can be indicated for the new demand for a sustainable livestock activity.

The study objective was to investigate the impact of beef genetics and finishing system on beef production and carcass merit. Red Angus (RA, n = 30) and RA x Akaushi (AK, n = 30) were equally assigned to one of two finishing treatments: a mixed-species pasture forage (GRASS) or a total mixed feedlot ration (GRAIN) in three replications. Each finishing treatment had free access to mineral and water, and GRAIN were fed once daily (20% hay and 80% concentrate) over 107 d. The grazing period was 80 d. Body weight (BW) was measured after a 12-hour fasting period at the onset and end of the trial. Animals were slaughtered at 18 and 26 mo (GRAIN and GRASS, respectively), and carcass data was collected 48 h postmortem. Initial and final BW were greater for GRAIN (469.7 and 611.0 kg) than GRASS (439.1 and 548.7 kg). Although steers had different total BW gain (141 kg for GRAIN vs 90 kg for GRASS; P &lt; 0.01), there was no difference for average daily gain between two systems. The GRAIN’s advantage in performance, led to higher HCW (+16%), ribeye area (+10%), and backfat (+52%) compared to GRASS. Dressing and marbling score were greater in GRAIN compared to GRASS (61.2 % and 621 vs 57.8 % and 417). The AK cattle presented higher values for dressing (58.7 vs 60.1%; P &lt; 0.0001), ribeye area (70.2 vs 74.3 cm2; P = 0.02), and marbling (548 vs 490, P = 0.03) compared to RA. There was genetics x diet interaction for internal fat, where AK animals had greater value than RA (2.7 vs 2.3%; P &lt; 0.0001) in the GRAIN treatment. These results indicate that GRAIN had superior performance and carcass merit and that AK enhanced these traits to a greater degree as compared to RA.