Frame score systems developed for Bos taurus breeds do not translate well for Bos indicus breeds, as these tend to be taller. We evaluated a novel frame score system for Nellore cattle raised on pasture [Guimaraes et al., 2020 J, Anim. Sci. 98 (Suppl. 4)]. Traits included adjusted scrotal circumference (cm) at 365 (SC365) and 450 (SC450) days of age, age at first calving (AFC, d), early heifer pregnancy (EHP, % calving as two-year-olds), stayability (STAY, % of cows remaining in the herd over 76 months of age, calving at least three times), and accumulated productivity (AP, kg of calf weaned per cow per year). In this study, we applied the previously developed equations (that also include hip height (HH, cm) and age to 12,049 records from the National Association of Breeders and Researchers (ANCP) database:FSmales= -20.35 + 0.1305*REA + 0.2633*BF - 0.5901*RF + 0.1139*HH + 0.0056*AGEFSfemales = -11.87 + 0.1316*REA - 0.2457*BF - 0.6218*RF + 0.1139*HH + 0.0009507*AGEThe (co)variance components and genetic parameters were estimated using a linear animal model or a threshold animal model depending on the trait. The heritability estimate for frame score was moderate (0.30). Estimated genetic correlations for reproductive traits were low to moderate (SC365, 0.06; SC450, 0.04; AFC, 0.18; EHP, -0.24; STAY, 0.06; AP, 0.25). The estimates support the notion that larger frame animals are later maturing but have greater lifetime productivity. The new frame score may be a useful tool for genetic selection of animals that are best suited to their environment.
Frame score (FS) systems for beef cattle generally represent the relationships among growth, body composition, reproduction and mature size, in a simple and practical form. This study aimed to: 1) develop a FS system for Nelore cattle that is biologically sound, easy to interpret, and useful for producers; and 2) estimate the genetic parameters of the FS with productive and reproductive traits. An arbitrary scale (1 to 12) was devised so that each unit corresponds to 15 kg of carcass weight (1 @), as this is a common measure used for marketing beef cattle in Brazil. Therefore, ideal carcass weight, defined as having 6 mm of backfat, would be 18 @ (269 kg) and 15 @ (224 kg) for FS = 6 males and females, respectively. Data from 36,030 animals (22,405 males, 13,565 females) raised on pasture were obtained from participating herds of the National Association of Breeders and Researchers (ANCP). Genetic parameters were estimated in uni- and bicharacteristic analyses under an animal model, using the EM-REML algorithm (AIREMLF90) and Bayesian inference (GIBBS1F90). The heritability estimate for the new FS was 0.38, and its additive genetic correlations were 0.70, 0.72, 0.77, 0.33, -0.57, 0.27, and 0.28 with BW at 365 d, BW at 450 d, hip height, longissimus muscle area, subcutaneous fat thickness, scrotal circumference at 450 d, and age at first calving, respectively. The estimated heritability and genetic correlations indicate that there is enough additive genetic variability to allow for genetic response to selection. The estimates support the notion that larger frame animals are taller, heavier, leaner and later maturing, both in body composition as well as sexually. The new frame score may be a useful tool for genetic selection of animals that are best suited to their environment.
We evaluated a novel frame score system for Nellore cattle raised on pasture (Guimarães et al., 2020 J, Anim. Sci. 98 (Suppl. 4)). Growth traits included age-adjusted weights (kg) at birth (W0), 120 (W120), 210 (W210) and 450 (W450) days of age, and adult weight (AW). Carcass traits (by ultrasound) included ribeye area (REA, cm2), 12th-13th rib backfat (BF, mm), rump fat (RF, mm), and intramuscular fat (IMF, %). Feed efficiency traits included residual feed intake (RFI, kg of DM/d) and DM intake (DMI, kg/d). We applied the previously developed equations (that also include hip height (HH, cm) and age to 12,049 records from the National Association of Breeders and Researchers (ANCP) database:FSmales= -20.35 + 0.1305*REA + 0.2633*BF - 0.5901*RF+ 0.1139*HH + 0.0056*AGEFSfemales = -11.87 + 0.1316*REA - 0.2457*BF - 0.6218*RF + 0.1139*HH + 0.0009507*AGEThe (co)variance components and genetic parameters were estimated using a linear animal model or a threshold animal model depending on the trait. The heritability estimate for frame score was moderate (0.30). Estimated genetic correlations were moderate for growth traits (W0, 0.51; W120, 0.41; W210, 0.35; W450, 0.29; AW, 0.39). Estimated genetic correlations for carcass and efficiency traits ranged from low to high (REA, 0.50; BF, -0.25; RF, -0.84; IMF, -0.15; DMI, 0.29; RFI, 0.10). The estimates support the notion that larger frame animals are heavier, leaner and later maturing, and less feed efficient. The new frame score may be a useful tool for genetic selection of animals that are best suited to their environment.
Resumo Um novo sistema de escore para estrutura corporal foi desenvolvido para bovinos Nelore, baseado em pesos de abate ideais para atingir os graus desejados de cobertura de gordura da carcaça. Dados de 688 registros completos incluindo sexo, idade, peso, altura do quadril e gordura subcutânea de bovinos Nelore em crescimento (190 machos e 498 fêmeas) foram obtidos da Associação Nacional de Criadores e Pesquisadores (ANCP), Ribeirão Preto – SP, Brasil. Os dados de peso foram regredidos por sexo, idade, altura do quadril e cobertura de gordura como covariáveis. A idade foi então fixada em 550 dias e a cobertura de gordura foi fixada em 6 mm, e novas equações para escores de estrutura corporal (1 a 11) em bovinos Nelore foram desenvolvidas: FrameNelore (machos) = -42,43 + 0,04919 × Idade + 0,3368 × Altura – 0,0003369 × Idade × Altura e FrameNellore (fêmeas) = -41,76 + 0,04919 × Idade + 0,3368 × Altura – 0,0003369 × Idade × Altura (Idade e Altura em dias e cm, respectivamente). As equações de Nelore resultaram em estrutura corporal médio de 5,3, variando de 2,3 a 7,7. Os valores foram semelhantes para machos (5,4) e fêmeas (5,3). Por outro lado, as equações anteriores deram valores mais altos, que eram muito diferentes entre machos e fêmeas. As novas pontuações de estruturacorporal no Nelore parecem razoáveis, principalmente em relação à composição corporal.
A new frame score system was developed for Nellore cattle, based upon ideal slaughter weights to achieve desired degrees of carcass fat cover. Data consisting of 688 complete records including sex, age, weight, hip height, and subcutaneous fat on growing Nellore cattle (190 males and 498 females) were obtained from the National Association of Breeders and Researchers (ANCP), Ribeirão Preto – SP, Brazil. Weight data were regressed on sex, age, hip height, and fat cover as covariates. Age was then fixed at 550 days and fat cover was set to 6 mm, and new equations for frame scores (1 to 11) in Nellore cattle were developed: FrameNellore (males) = -42.43 + 0.04919 × Age + 0.3368 × Height – 0.0003369 × Age × Height and FrameNellore (females) = -41.76 + 0.04919 × Age + 0.3368 × Height – 0.0003369 × Age × Height (Age and Height in days and cm, respectively). The Nellore equations resulted in average frame of 5.3, ranging from 2.3 to 7.7. Values were similar for males (5.4) and females (5.3). By contrast, previous equations gave higher values, that were very different between males and females. The new Nellore frame scores appear reasonable, particularly regarding body composition.
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