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The aims of this study were (1) to assess if there is phenotypical divergence for feed efficiency (FE) during the preweaning phase; (2) if FE is correlated with heat production (HP) measured by the face mask method or (3) by surface skin temperature via thermography, and (4) whether these methods are applicable to preweaned calves. Holstein × Gyr heifer calves (n = 36, birth body weight = 32.4 ± 6.6 kg) were enrolled and on trial between 4 and 12 wk of age and were classified into 2 residual feed intake (RFI) and residual body weight gain (RG) groups: high efficiency (HE; RFI, n = 10; and RG, n = 9) and low efficiency (LE; RFI, n = 10; and RG, n = 8). Calves were fed milk (6 L/d) and solid feed (95% starter and 5% chopped Tifton 85 hay, as fed). Growth was monitored weekly and feed intake (milk and solid feed) daily, during the whole period. Gas exchanges (O consumption and production of CO and CH) were obtained using a face mask at 45 ± 5 d of age and HP was estimated. Maximum temperatures were measured at 7 sites with an infrared camera at 62 ± 7 d of age. There was divergence in RFI and RG. Respectively, HE and LE calves had RFI of -0.14 and 0.13 kg/d, and RG of 0.05 and -0.07 kg/d. Dry matter intake was 15% lower in HE-RFI compared with LE-RFI, but no differences were observed in average daily weight gain. Within the RG test, no differences were observed in dry matter intake or average daily gain. The HE-RFI calves consumed less O (L/d) and produced less CO (L/d). Heart rate and HP were lower for HE-RFI calves compared with LE-RFI. Residual feed intake was correlated with HP (r = 0.48), O consumption (r = 0.48), CO production (r = 0.48), and heart rate (r = 0.40). No differences were observed in HP and gas exchanges between RG groups. Methane production was null in both groups. Eye temperature measured by thermography was 0.5°C greater in HE-RG than LE-RG calves. Differences in skin temperature between HE and LE calves were not observed at the other sites. These results support the hypothesis that calves are divergent for RFI, RG, and FE during preweaning and divergence tests are applicable during this phase. The face mask method described here is a useful tool for estimating differences in HP among phenotypically divergent RFI calves. Eye temperature measured by infrared thermography may have potential to screen phenotypically divergent RG calves.

ABSTRACT.-Molina L.R., Costa H.N., Leão J.M., Malacco V.M.R., Facury Filho E.J., Carvalho A.U. & Lage C.F. A. 2017. Efficacy of an internal teat seal associated with a dry cow intramammary antibiotic for prevention of intramammary infections in dairy cows during the dry and early lactation periods. Pesquisa Veterinária Brasileira 37 (5) , Florham Park, Nova Jersey, USA), in preventing new infections during the dry-off and early postpartum period. A total of 150 Holstein cows (average production of 9,000 kg of milk per lactation), with four functional udder quarters without clinical mastitis was included in the study. All animals were dried-off 60 days before the expected calving date. Two teats positioned diagonal-contralaterally received only dry cow antibiotic, control group C (n=300) and the other two teats, treatment group T (n=300) received dry cow antibiotic and infusion with an internal teat seal. Data from SCC variable were transformed by log base-10 transformation. Duncan's test was used accepting 5% as the level of statistical significance. The occurrence of intramammary infection (IMI) and chronicity rate, and frequency of microorganisms isolated at drying and immediately postpartum in teats of group C and group T were evaluated using a non-parametric Chi-square Test, accepting 10% as the statistical significance level. There was a decrease in the occurrence of new infections in the early postpartum in cows which the sealant was used (C=19.6%, T=11.4%). In the postpartum period, Gram-negative bacteria were isolated from 16 teats in C and seven in T. The greatest reduction was observed for Escherichia coli (8 vs 1) in group T. There was no effect using the internal sealant on the frequency of isolation of environmental Streptococus. The use of sealant reduced the prevalence of subclinical mastitis cows between drying-off and the early postpartum period (C=51% versus T=42%) and resulted in a lower somatic cell count (SCC) in the treatment group when compared with the control group (T=1,073x10). The use of the internal teat seal combined with dry cow antibiotic is effective in the prevention of IMI during the dry period and early lactation and results in the reduction of SCC in immediate postpartum period. The treatment is effective in reducing infection between dry-off and the immediate postpartum caused by major and minor pathogens. However, no effect on infections caused by contagious pathogens was observed. , Florham Park, Nova Jersey, EUA) em prevenir novas infecções durante o perío-do seco e pós-parto imediato. Foram utilizadas 150 vacas Holandesas (produção média de 9,000 kg de leite por lactação), com os quatro quartos mamários funcionais e sem mastite clínica, que foram secas 60 dias antes da data prevista para o parto. O teto constituiu a unidade experimental. O grupo controle (C) foi representado por dois tetos diagonais-contralaterais (n=300), que receberam somente o antibiótico de vaca seca. Os outros dois tetos (n=300) constituíam o grupo tratado (T) e recebiam o antibiótico de vaca seca as...

RESUMOAvaliaram-se o efeito do ganho compensatório no desempenho produtivo e a eficiência econômica de novilhos submetidos a diferentes estratégias de suplementação alimentar na fase de recria e engorda. Cinquenta e quatro bezerros, com peso médio inicial de 169,6±16,7kg, foram divididos em oito tratamentos, sendo cada tratamento uma estratégia de suplementação alimentar. No período da seca, os animais receberam suplemento proteico-energético-mineral (SP), com ingestão média diária de 0,1 ou 0,2% do peso vivo. No período das águas, os novilhos receberam SP com ingestão média diária de 0,5% do peso vivo ou suplementação mineral (SM). No período de terminação, os animais receberam SP com ingestão média diária de 1,4% do peso vivo ou foram confinados. Os animais que receberam SM não tiveram ganho compensatório. Animais que receberam SP nas águas (0,51±0,07kg/dia) tiveram ganho compensatório em relação ao período anterior e obtiveram ganho adicional diário de 123g quando comparados com SM (0,39±0,07kg/dia), entretanto não obtiveram ganho compensatório na fase de terminação. O efeito do ganho compensatório é muito pequeno ou até mesmo nulo no sistema de recria e engorda precoce com terminação em confinamento. A suplementação com menor ingestão de proteína, energia e mineral durante a primeira seca e águas, pós-desmame, da vida de novilhos pode ser compensada com o uso do confinamento na fase de terminação desses animais com resultados econômicos positivos.Palavras-chave: bovino de corte, confinamento, pasto, rentabilidade, suplementação ABSTRACT The effect of compensatory growth on performance and economical efficiency of steers on different dietary supplementation strategies in the rearing and fattening stages was evaluated. Fifty-four calves with average initial weight of 169.6±16.7kg were divided into eight treatments, each of them being a strategy of food supplementation. During the dry season the animals received protein -energy -mineral supplement (SP) with an average daily intake of 0.1 or 0.2 % of body weight (BW). During the rainy season the animals received SP with an average daily intake of 0.5 % of body weight or mineral supplementation (SM

Comparou-se o desempenho de bovinos de diferentes grupos genéticos quanto a algumas características produtivas da desmama até o abate. Os dados são referentes a 827 bovinos machos oriundos do cruzamento de vacas Tabapuã com touros Tabapuã (TAB), Red Angus (REDTAB), Santa Gertrudis (STATAB), e das fêmeas TabapuãxRed Angus com touros Santa Gertrudis (STAREDTAB) (nascidos entre 1999 e 2001 e criados em pastagens de braquiária, no Estado da Bahia). Foram analisados o peso à desmama ajustado aos 205 dias (PD205), o peso ao abate (PA), o ganho médio diário da desmama ao abate (GMD) e a idade ao abate (IA). O grupo contemporâneo (GC), o grupo genético (GG) e a interação entre GC e GG influenciaram as características avaliadas (P<0,05). O REDTAB apresentou superioridade entre os GG para GMD no primeiro ano do GC (1GC), com média de 0,552kg (P<0,05). Os cruzados STATAB e STAREDTAB não apresentaram diferenças significativas para as médias de GMD (P>0,05); entretanto, apresentaram médias inferiores às do grupo REDTAB e TAB. Em condição de ambiente mais favorável, o REDTAB pode ser mais precoce, obtendo maior GMD e PA com menor IA, sendo superior ao Tabapuã e aos cruzados da segunda geração (F2). Os cruzados F2 não demonstraram vantagem em relação ao cruzado F1 e à raça pura.

-The study evaluated the average return on invested capital (ROIC) in function of the variations in the historical prices of beef cattle and the odds of return on that capital gain within the system of beef cattle fattening on a farm in the state of Minas Gerais, Brazil, from 2004 to 2007. To calculate the risk of ROIC, monthly data of beef cattle prices (BM&F) were used from July 1997 to December 2013, revised by the General Price Index of the Fundação Getúlio Vargas in December 2013. The corrected data were divided into five classes that correspond to the risk scenarios. In light of these classes, the observed frequencies and their respective probabilities were calculated. The cumulative and updated ROIC were -3.02 and 0.24%, respectively. The odds for obtaining returns above 8.4% (Brazilian Selic Rate) per year were median, corresponding to 32.0 and 34.94% for the calculation of operating profit (ROIC OP) and total profit (ROIC TP), respectively. The expected average annual return was 6.26 and 7.66% for ROIC OP and ROIC TP, respectively. The standard deviation and coefficient of variation showed a high risk of ROIC because the scale and extent of dispersion per unit of expected return were elevated in the accumulation period and the risk for 2013 was reduced according to the price of beef cattle. The expected risk of ROIC was considered high between 2004 and 2007 and average for 2013. The probability of return on capital invested in the intensification of fattening beef cattle is a function of the selling price of cattle and purchase of inputs, in which the high scenario ranching provides greater probability of getting a return above the bank interest rates.

Avaliou-se o desempenho produtivo e a eficiência econômica de diferentes estratégias de suplementação alimentar na fase de recria e engorda de novilhos Nelore. O experimento foi dividido em três períodos, seca, água e terminação. Cinquenta e quatro bezerros com peso médio inicial de 169,6kg foram divididos em oito tratamentos, sendo cada tratamento uma estratégia de suplementação alimentar. No período da seca, os animais receberam suplemento proteico-energético-mineral com ingestão média diária de 0,1% do peso vivo médio (PV) para os tratamentos A, B, C, D, e 0,2% do PV para os tratamentos E, F, G e H. No período das águas, os novilhos dos tratamentos A, B, E e F receberam suplemento proteico-energético-mineral com ingestão média diária de 0,5% do PV, e os novilhos dos tratamentos C, D, G e H receberam suplementação mineral. No período de terminação, os animais dos tratamentos B, D, F e H receberam suplemento proteico-energético-mineral com ingestão média diária de 1,4% do PV, e os animais dos tratamentos A, C, E e G foram engordados em confinamento. Houve diferença estatística (p<0,05) para o peso final acumulado (PF). Os maiores valores de PF foram de 492,0; 475,1 e 473,1kg para os animais dos tratamentos F, B e H, respectivamente. Os animais dos tratamentos que receberam suplemento 1,4% do PV na terminação permaneceram 70 dias a mais do que os animais que foram engordados em confinamento. Todas os tratamentos foram economicamente viáveis, contudo o tratamento G apresentou o maior resultado de caixa, VPL e TIR, sendo eles R$349,00; R$252,10 e 2,45%, respectivamente. A suplementação de proteína, energia e minerais a pasto ou em confinamento reduziu a idade ao abate dos animais e constitui uma alternativa economicamente viável para produção de bovinos de corte.

The aim of this study was to evaluate the consumption, performance, feed efficiency, glucose concentration, and the cost per kilogram of weight gain of crossbred Holstein-Gyr heifers (n = 33) subjected to one of the three waste milk step-down strategies: 6L-30d/4L-60d/2L-90d (T1), 6L-45d/4L-60d/2L-90d (T2), and 8L-30d/6L-60d/3L-90d (T3). Heifers were weaned at the age of 91 days. Water and starter were provided ad libitum. The average waste milk intake was higher in T3 than in T1 and T2 strategies until 30 days and between 60 and 90 days. The starter intake did not differ among the strategies until 45 days, but it was higher in strategy T1 than in strategy T3 between 60 and 90 days. The waste milk step-down strategy did not influence the total dry matter intake, average daily gain, body weight, and feed efficiency. Glucose concentrations in plasma varied within a range that could be considered normal and were similar among the treatments. The average cost per kilogram of weight gain was the lowest in strategy T1 (US$3.0) compared to that in the other strategies (T2, US$3.2, and T3, US$3.6). The 6L-30d/4L-60d/2L-90d waste milk step-down strategy was the most effective, since it increased the starter intake, led to normal glucose concentrations in plasma, and caused similar weight gain compared with the other strategies; however, it had a lower cost per kilogram.