This study assessed milk yield and composition of Angus and Angus-cross beef cows raised in southern Brazil. A total of 128 records were collected in 2 consecutive calving seasons from cows between 3 and 5 yr of age of 4 breed compositions: Angus (ANAN), Caracu × Angus (CRAN), Hereford × Angus (HHAN), and Nelore × Angus (NEAN). These cows were mated to Brangus (BN) or Braford (BO) bulls and managed under extensive grazing conditions in southern Brazil. Milk production of these cows was assessed by 2 procedures: indirectly by the calf weigh-suckle-weigh procedure (WD) and directly by machine milking (MM). Lactation curves were estimated using nonlinear regression and the following related traits were derived: peak yield (PY), peak week (PW), total yield at 210 d (TY210), and lactation persistence (PERS). Milk composition and calf weaning weight adjusted to 210 d (WW210) were also determined. The MM technique was considered more accurate because of lower standard errors of estimated means, greater statistical power, and greater correlation between TY210 and WW210 (0.50) compared to WD (0.36). Considering the more precise evaluation by MM, the CRAN and NEAN cows had greater TY210 (1070 and 1116 kg, respectively) and PY (8.1 and 7.8 kg, respectively) compared to ANAN and HHAN cows, which had 858 and 842 kg for TY210 and 6.6 and 6.3 kg for PY, respectively. The NEAN cows had the latest PW at 10.8 wk. Late-calving cows had 21% lower TY210 compared to cows that calved earlier. Milk composition was influenced by cow genotype, with CRAN and NEAN cows producing milk with greater fat (3.8 and 3.9%, respectively) and protein (3.2 and 3.1%, respectively) content compared to ANAN and HHAN cows. Regardless of the genotype, fat, protein, and total solids increased in concentration from beginning to end of lactation, while lactose content decreased. Crossbreeding of Angus with adapted breeds of taurine or indicine origin can be effective in increasing milk yield and nutrient content and, consequently, producing heavier calves at weaning under extensive grazing in southern Brazil and other similar subtropical climate regions.

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RESUMO Objetivou-se avaliar o desempenho e características de cordeiros Santa Inês e suas cruzas desmamados aos 75 dias de vida e terminados em confinamento. Foram utilizados 30 cordeiros não castrados, 10 Santa Inês, 10 ½Dorper × ½Santa Inês e 10 ¾Dorper × ¼Santa Inês, com idade e peso vivo médio no início do experimento de 82 dias e 19,40 kg, respectivamente. Foi utilizada dieta única contendo 169,0 g/kg de proteína bruta e 2,80 Mcal/kg MS. Não houve efeito do genótipo sobre o desempenho dos cordeiros, exceto para escore corporal final, em que os mestiços Dorper alcançaram os maiores escores. As carcaças dos cordeiros ½Dorper × ½Santa Inês e ¾Dorper × ¼Santa Inês apresentaram maior largura da garupa, área de olho de lombo e percentual de lombo do que as carcaças dos cordeiros Santa Inês. As carcaças dos cordeiros ¾Dorper × ¼Santa Inês alcançaram maior largura do tórax e do anterior quando comparadas com as carcaças dos cordeiros Santa Inês, tendo obtido também melhor conformação e acabamento de carcaça quando comparadas com as carcaças dos demais genótipos. Entretanto, as carcaças dos cordeiros Santa Inês e ½Dorper × ½Santa Inês apresentaram maior percentual de pescoço em relação às carcaças dos cordeiros ¾Dorper × ¼Santa Inês.

SUMMARY This study evaluated the characteristics of carcass and commercial cuts of Santa Ines lambs of different biotypes (traditional and modern) slaughtered at 32 kg and 34 kg. The thirty-six Santa Ines sheep used, of which 18 traditional and 18 modern biotypes were on average 180 days old and weighed 16 kg initially. The animals were kept in individual stalls (0.80 × 1.20 m) until they reached the slaughtering weight. The experimental design was completely randomized, factorial 2×2 (two biotypes x two slaughtering weights). The traditional biotype influenced significantly (P<0.05) the carcass yields, conformation, and marbling, compared to the modern biotype. The biotype did not influence (P> 0.05) carcass morphometric measurements and commercial cuts. On the other hand, the 34-kg slaughtering weight affected most of carcass characteristics. The traditional biotype displayed higher yield, better conformation and greater amount of intramuscular fat in the carcass. The higher slaughtering weight influenced carcass characteristics and the amount of fat. Generally, the carcasses presented high muscle proportion and fat amount appropriate to the consumer.