title: Milk yield and composition from Angus and Angus-cross beef cows raised in southern Brazil.
abstract: 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.
authors.affiliation: Animal Science Department, Federal University of Pelotas, 96010-900 Pelotas, Brazil.
authors.forename: P F
authors.initials: PF
authors.lastname: Rodrigues
authors.affiliation: Animal Science Department, Federal University of Pelotas, 96010-900 Pelotas, Brazil Agro-industrial Technology College, University of Rio Grande do Sul State, 97573-011 Sant'Ana do Livramento, Brazil.
authors.forename: L M
authors.initials: LM
authors.lastname: Menezes
authors.affiliation: Animal Science Department, Federal University of Pelotas, 96010-900 Pelotas, Brazil.
authors.forename: R C C
authors.initials: RC
authors.lastname: Azambuja
authors.affiliation: Embrapa Southern Region Animal Husbandry, 96401-970 Bagé, Brazil.
authors.forename: R W
authors.initials: RW
authors.lastname: Suñé
authors.affiliation: Animal Science Department, Federal University of Pelotas, 96010-900 Pelotas, Brazil.
authors.forename: I D
authors.initials: ID
authors.lastname: Barbosa Silveira
authors.affiliation: Animal Science Department, Federal University of Pelotas, 96010-900 Pelotas, Brazil Embrapa Southern Region Animal Husbandry, 96401-970 Bagé, Brazil National Council for Scientific and Technological Development,71605-001 Brasília, Brazil fernando.cardoso@embrapa.br.
authors.forename: F F
authors.initials: FF
authors.lastname: Cardoso
mesh_terms: D000818:Animals; D001835:Body Weight / Q000502:physiology*; D001938:Brazil; D001947:Breeding / Q000379:methods*; D002417:Cattle / Q000502:physiology*; D003433:Crosses, Genetic; D005260:Female; D005838:Genotype; D007774:Lactation / Q000502:physiology*; D008892:Milk / Q000737:chemistry*; D012044:Regression Analysis
keywords: beef cattle; crossbreeding; lactation curve; milk production; productivity; weaning weight