One of the main drivers influencing consumers in the purchasing of red meat is the level of visible fat, and this is particularly important in lamb, with lamb often being perceived as fatty. Consumer-driven preference for leaner meat, coupled with the meat processing industries preference for a reduction in carcass fat, increasing lean meat yield and reducing waste, have led to continued selection for lean growth and reduced fatness in several meat producing species The perception of lamb being fatty could be directly targeted in isolation by reducing overall fat levels, however there are related effects on meat (eating) quality, and the combined improvement and consistency of meat (eating) quality and the reduction of overall fatness is more complicated. It is apparent that fat content plays a significant role in meat (eating) quality. Generally four major fat depots are recognised in animal carcasses, these are: subcutaneous (under the skin); internal organ associated; intermuscular (between muscles and surrounding muscle groups); and intramuscular (marbling, between muscle fibres), the latter generally regarded as having the greatest association with meat (eating) quality. X-ray computed tomography (CT) can measure fat, muscle and bone in vivo in sheep and CT predictions of carcass composition have been used in commercial UK sheep breeding programmes over the last two decades. Together with ultrasound measures of fat and muscle depth in the loin region, CT measured carcass fat and muscle weights have contributed much to the success of breeding for leaner carcasses and increased lean meat yield. Recently it has also been considered that x-ray computed tomography provides the means to simultaneously estimate IMF and carcass fat in vivo. Thus the aim of this project is to investigate the use of two and three-dimensional x-ray computed tomography techniques in the estimation of meat (eating) quality traits in sheep, and to further investigate the genetic basis of these traits and the possibility of their inclusion into current breeding programmes. The primary approach was the use of two-dimensional x-ray computed tomography, determining the most accurate combination of variables to predict IMF and mechanical shear force in the loin. The prediction of mechanical shear force was poor with accuracies ranging from Adj R2 0.03 – 0.14, however the prediction of IMF in the loin was more promising. CT predicted carcass fat weight accounted for a moderate amount of variation in IMF (R2 =0.51). These accuracies were significantly improved upon by including other information from the CT scans (i.e. fat and muscle densities, Adj R2 >0.65). Average muscle density in a single or multiple scans accounted for a moderate amount of the variation in IMF (Adj R2 = 0.51-0.60), and again accuracies R2 >0.65 were achieved, independent of CT-measured fat areas or predicted fat weights. Similar results were achieved with the use of three-dimensional CT scanning techniques (Adj R2 0.51 – 0.71), however, there was a dramatically increased requirement for image analysis when compared to two-dimensional techniques, and the increase in accuracy was not significant. This suggests that the current method of two-dimensional image capture is sufficient in the estimation of IMF in vivo in sheep. The prediction equations developed as part of this work were applied across divergent breed types (Texel, Scottish Blackface and Texel cross mule), to investigate the transferability of the prediction equations directly across to other breeds of sheep. As part of this study, the IMF levels across the breed types and sexes were also compared and found that IMF was significantly affected by breed type (P<0.001) with Scottish Blackface lambs having higher levels of IMF when compared to Texel cross mule lambs, and the lowest levels of IMF were in the purebred Texel lambs at the same liveweight or similar levels of carcass fatness. Sex also had a significant effect on IMF across breeds (P<0.001) with females having higher levels of IMF at similar levels of both carcass fat and liveweight, and within breed, females had significantly higher levels of IMF in both the purebred Texel and Scottish Blackface lambs, when compared at similar levels of carcass fat and liveweight (P<0.05). Using the models previously developed in purebred Texel to predict IMF in the Scottish Blackface and Texel cross mule, accuracies were found to be R2 = 0.57 – 0.64 and R2 = 0.37 – 0.38 respectively. Providing evidence that the equations are transferable across to some breeds more successfully than others, however, given that there is currently no method of accurately estimating IMF in vivo, accuracies across to both breeds are acceptable. The genetic parameter estimation was unsuccessful using the same research-derived dataset as previously employed in the study. However the ambition was always to investigate the genetic relationships between traits in a large industry dataset, exploiting the wealth of commercial CT information available. These investigations were considerably more successful, and among the first to present genetic parameters of novel CT-derived IMF estimates. The results found moderate heritability estimates of h2 0.31 and 0.36 for the final selected prediction equations, with clear indications that one model not including CT predicted carcass fat or any other fat measures, was more independent of these measures and the two separate prediction methods were highly genetically correlated with each other (rg = 0.89). The results from this study show that not only is it possible to accurately estimate IMF levels in the loin of Texel sheep using CT scanning, but that, until breed specific predictions are developed, the methods developed in this study are transferable across some breed types. The results also show that CT predicted IMF is heritable, independent of overall fatness and has the potential to be included in current breeding programmes. These findings can now be used to develop breeding programmes which enable breeders to make the best use of CT scanning technology to improve carcass composition while maintaining or possibly improving aspects of meat (eating) quality.

Orientador: Pedro Eduardo de Felicio / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-10T03:26:36Z (GMT). No. of bitstreams: 1 PflanzerJunior_SergioBertelli_M.pdf: 3041050 bytes, checksum: 4c250d50371a5d13f85624668b3d27f0 (MD5) Previous issue date: 2008 / Resumo: A classificação pode ser utilizada para agrupar carcaças com características semelhantes de sexo, maturidade, peso, gordura de cobertura e conformação, visando uniformizar a qualidade e o rendimento da carne. No Brasil, há falta de informações científicas a respeito desses parâmetros. Objetivou-se nesta pesquisa avaliar o efeito da maturidade dentária e do acabamento de carcaças em atributos físicos, químicos e sensoriais do contrafilé de costela (m. L. thoracis). Meias carcaças (n=60) de machos castrados da raça Nelore foram selecionadas no abate de 822 bovinos, em uma das etapas do Circuito Boi Verde. Foram em seguida agrupadas em 6 categorias, de acordo com a maturidade dentária (2, 4 e 6 dentes incisivos permanentes), e acabamento (2 ¿ escassa e 3 - mediana). O período de resfriamento foi de 24 h, e na desossa foram obtidas as porções de contrafilé, compreendidas entre a 5ª e a 9ª costela, que foram embaladas a vácuo, maturadas por 14 dias e congeladas a -18°C. Cinco bifes de 2,5 cm de espessura foram avaliados quanto à cor instrumental, no sistema CIE L*, a* e b*, e em análise visual para os atributos cor e mármore. Determinou-se o comprimento de sarcômero, a força de cisalhamento por Warner-Bratzler, as perdas de peso por cozimento e os atributos sensoriais de cada uma das sessenta amostras. Houve efeito (P<0,01) da maturidade sobre o peso das carcaças, que aumentou com o número de dentes incisivos permanentes. Carcaças com maiores grau de acabamento ou nível de maturidade apresentaram maiores teores de lipídios e menores teores de umidade (P<0,01) na carne. O comprimento de sarcômero não foi afetado (P>0,05) pela maturidade ou acabamento. A maturidade dentária não influenciou (P>0,05) a maciez do contrafilé medida por instrumento ou análise sensorial, mas a carne de carcaças com mais acabamento foi mais macia (P<0,01) e perdeu menos peso (P<0,01) na cocção. Não houve efeito (P>0,05) da maturidade no teor de mármore, nem na cor por análises visuais e instrumentais, enquanto as carcaças com mais acabamento tiveram maior teor de mármore (P<0,05) na avaliação visual, e maior valor de L (P<0,05) na análise instrumental da cor da carne. Concluiu-se que não se justificam bonificações pela qualidade do contrafilé de costela em função de maturidade, mas sim em função do acabamento / Abstract: Classification schemes are useful for grouping carcasses with similar characteristics of sex, maturity, fatness and conformation, aiming to keep homogeneity of quality and yields within classes. In Brazil, there is a lack of scientific information on these classification parameters. The objective of this research was to evaluate the effects of teeth maturity and carcass fatness on the physical, chemical and sensory attributes of the boneless rib cut (m. L. thoracis). Carcass sides (n=60) from Nelore steers were selected at the kill floor among 822 heads of cattle in one of the ¿Circuito Boi Verde¿ (green steers circuit) carcass contests. They were grouped in 6 categories according to teeth maturity (2, 4 and 6 permanent incisors), and fatness (fat cover 2- slight; 3-medium). The chilling time was 24 hrs, and then a boneless rib section between the 5th and 9th rib from each side was obtained, vacuum packaged, aged for 14 days and frozen. Five 2,5 cm steaks were evaluated for instrumental color in the CIE L*, a*, e b* scheme, and in visual analysis for color and marbling. Sarcomere length, Warner-Bratzler shear force, cooking losses and sensory attributes with a trained panel were determined. There was effect (P<0,01) of maturity on carcass weight, which increased with the number of permanent incisors. Carcasses with higher degree of fatness or maturity level presented increased percentage of lipids and lower (P<0,01) moisture in the meat. The sarcomere length was not affected (P>0,05) by maturity or fatness. Teeth maturity did not affect (P>0,05) the WB shear force or the sensory tenderness of the rib steaks, while the meat from higher level of fatness was more tender (P<0,01) and showed lower cooking losses (P<0,01). No effects (P>0,05) of maturity in marbling degree, and in instrumental or visual color were detected, while samples from higher fatness level carcasses had higher level of marbling (P<0,05), and higher (P<0,05)L value. It was concluded that bonuses aiming at the quality of boneless rib cut would not be justifiable for young maturity, but it would so for carcass fatness / Mestrado / Mestre em Tecnologia de Alimentos

Objetivou-se neste trabalho avaliar algumas características da carne de bovinos Nelore, analisando as diferenças entre as progênies (machos e fêmeas) de touros representativos das principais linhagens desta raça e comparar as progênies (machos e fêmeas) dos grupos genéticos Nelore, ½ Angus x Nelore e ½ Brahman x Nelore. Quartorze touros, raça Nelore, dois Aberdeen Angus e um Brahman foram acasalados com 400 vacas comerciais da raça Nelore formando progênies de Nelore (NE), ½ Aberdeen Angus x Nelore (AN) e ½ Brahman x Nelore (BN). Os animais foram confinados por 127 dias, recebendo alto teor de concentrado. Foram abatidos 293 bovinos, determinados o pH e a temperatura das carcaças e avaliados o grau de acabamento das carcaças. Após 24 horas de resfriamento calculou-se o rendimento das carcaças (RC), a área de olho de lombo (AOL) a espessura de gordura subcutânea (EGS) e foi determinado o índice de marmorização no m. Longissimus dorsi. Retiraram-se duas amostras desse músculo, as quais foram maturadas por 14 dias para as análises de força de cisalhamento (FC), perda de água por exsudação (PAE), perdas ao cozimento (PAC) e índice de fragmentação miofibrilar (MFI). Houve interação entre sexos e gupos genéticos para as características de peso vivo final (PVF), rendimento de carcaça (RC) e área de olho de lombo (AOL). Houve diferenças entre sexos e grupos genéticos para o peso de carcaça quente (PCQ) e para a espessura de gordura subcutânea (EGS). A marmorização e a força de cisalhamento foram influenciadas pelos grupos genéticos. O pH, e a temperatura (1 hora pós-morte) não foram influenciados pelos sexos e grupos genéticos, assim como as perdas ao cozimento (PAC) e o índice de fragmentação miofibrilar (MFI). O sexo influenciou nas características de acabamento das carcaças, pH e temperatura (24 horas pós-morte) e nas perdas de água por exudação (PAE). Quando analisadas as diferenças entre as progênies de touros representativos das principais linhagens da raça Nelore houve interação entre sexo e touros para o PVF, PCQ e EGS. Houve diferenças entre sexos e touros para as características de acabamento, RC, AOL e marmorização. Não foram detectadas diferenças entre sexos e entre touros para o pH e temperatura (1 hora pós-morte), PAC e maciez por meio da força de cisalhamento. O sexo influenciou o pH e a temperatura (24 horas pós-morte), assim como a PAE e o MFI do m. Longissimus dorsi maturado por 14 dias também foram influenciados. Constatou-se superioridade dos animais cruzados, em relação aos zebuínos puros, quanto a algumas características de qualidade da carne, com variação dentro da raça Nelore. Foram identificados touros, cujos filhos produziram carne com os melhores padrões de qualidade para o mercado mundial. / This work aimed to evaluate some meat characteristics of Nellore cattle. The differences among the progenies (males and females) of representative sires of the main lines of this breed and also of Nellore, ½ Angus ½ Nellore and ½ Brahman ½ Nellore genetic groups were analyzed. Fourteen Nellore, two Aberdeen Angus and one Brahman bull, were mated to 400 Nellore cows to obtain the Nellore, ½ Angus ½ Nellore and ½ Brahman ½ Nellore progenies. The animals were fed on feedlot during 127 days with high concentrate diets and after the slaughter of 293 animals the pH, temperature and classification of the carcass was performed. After 24 hours chilling the carcass dressing percentage, rib eye area, fat thickness and marbling index of the Longissimus dorsi m. were determined. Two samples of this muscle were collected and aged during 14 days for shear force, water loss, cocking loss and myofribrilar fragmentation index (MFI) determination. There was an interaction between sex ad genetic groups for final live weight, carcass dressing percentage and rib eye area. There were differences between sex and genetic groups in carcass weight and fat thickness. Marbling and shear force were affected by genetic group. The pH and the temperature one hour after slaughter were not affected by sex and genetic group, as well as cocking loss and myofibrilar fragmentation index. Sex affected the finishing characteristics of the carcass, the pH and temperature 24 hours after slaughter and the water loss. Among the progeny of Nellore sires there was an interaction between sex and bull for final live weight, carcass weight and fat thickness. There were differences between sex and sires in the finishing characteristics, carcass dressing percentage, rib eye area and marbling. No differences were detected between sex and sires in pH and temperature one hour after slaughter, cocking loss and tenderness with Warner Bratzler Shear Force. Sex affected pH and temperature 24 hours after slaughter, as well as water loss and MFI of the Longissimus dorsi m. were affected. It was observed superiority of the crossbred steers in some meat quality characteristics, but also large variation inside the Nellore breed. The progeny of some Nellore sires produced meat with enough quality for the world market.

Doctor of Philosophy / Department of Animal Sciences and Industry / Michael E. Dikeman / Two experiments were conducted to evaluate the effects of dietary vitamin A on growth, carcass characteristics, and meat quality of ruminants. In Experiment 1, 40 crossbred wethers (BW = 28.7 kg) were assigned to 1 of 4 treatments: backgrounding (BG) and finishing (FN) with no vitamin A (LL); BG with no vitamin A, FN with high vitamin A (6,600 IU[dot in middle of line]kg [superscript-1] diet) (LH); BG with high vitamin A and FN with no vitamin A (HL); and BG and FN with high vitamin A (HH). During BG (d 1 to 56), intake was restricted to achieve 0.22 kg ADG. During FN (d 57 to 112), lambs consumed the same diet ad libitum. Lambs were humanely slaughtered after 112 d. There were no treatment differences (P > 0.05) in feed intake, ADG, or final BW. Carcasses from the HH group had higher (P < .05) marbling scores (514 vs. 459), and 25.8 % more extractable intramuscular lipid (IMF) than LL (3.88 vs. 3.08 % for HH and LL, respectively, P < .05); the LH and HL treatments were intermediate. The was a negative correlation (r = -0.38) between serum fatty acid content and %IMF. Experiment 1 data suggest that increased marbling may be achieved with high vitamin A for 112 d in lambs. In Experiment 2, Angus crossbred steers (n = 48), were either early-weaned (EW) at 137[plus or minus]26 d of age or weaned at a traditional age (TW) 199[plus or minus]26 d and allotted to either 42,180 IU vitamin A[dot in middle of line]hd[superscript-1][dot in middle of line]d[superscript-1] (HA) or no vitamin A (NA). Early- and TW steers consumed treatments for 235[plus or minus]17 and 175[plus or minus]18 d, respectively. Serum and liver retinol content diverged dramatically (both, P < 0.01) by the end of the experiment and TW steers tended (P > 0.10) to have higher ADG than EW steers (1.31[plus or minus]0.2 and 1.48[plus or minus]0.2 kg[dot in middle of line]hd[superscript-1][dot in middle of line]d[superscript-1], respectively). Steers were humanely slaughtered at 1.02 cm fat. Weights tended (P = 0.08) to be heavier and carcasses were fatter (P < 0.05) for HA than NA. Marbling score and % IMF were higher (P < 0.05) for EW-NA than other treatments. Percentage of USDA Choice and Prime carcasses doubled (P < 0.05) for NA than HA. Yield grades increased (P < 0.05) with EW-HA and were similar (P > 0.10) among other treatments. Feeding NA was effective for increasing marbling without increasing fat; EW enhanced these effects. Reasons for the contradictory results in these 2 experiments are unclear. Species differences in the ability to metabolize retinol are implicated.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第20427号 / 農博第2212号 / 新制||農||1048(附属図書館) / 学位論文||H29||N5048(農学部図書室) / 京都大学大学院農学研究科応用生物科学専攻 / (主査)准教授 谷口 幸雄, 教授 今井 裕, 教授 廣岡 博之 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第21682号 / 医博第4488号 / 新制||医||1036(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 妻木 範行, 教授 大森 孝一, 教授 別所 和久 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

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Made available in DSpace on 2016-08-10T10:38:44Z (GMT). No. of bitstreams: 1 RAQUEL LOREN DOS REIS.pdf: 12987109 bytes, checksum: e29da03d256dabd02e5b926d34f70985 (MD5) Previous issue date: 2013-06-27 / The objective of this study was to evaluate the scientific information in the beef cattle breeding in the last 48 years (1964-2012). The data gathering was compiled using the SCOPUS database, through the key words beef* , cattle* and breeding* . We retained all articles that include information about year and period of publication, author nationality and filiation, document type and scientific area. We found 1.946 studies published between 1946 and 2012. We noted an expressive increase on studies about genetic breeding of beef cattle since the end of 80´s till 2004. From the total, we found 1.717 original articles. We found that 21 of the 169 authors were responsible by 30% of publications. The majority of the published articles were from agricultural and biological science (55%) areas of knowledge. On the journal evaluation, Journal of Animal Science was the first with 696 articles and the Revista Brasileira de Zootecnia, a Brazilian journal, was the fourth. When we evaluated the institutional filiation the USDA (75) was first, UNESP (72), USP (54) and Embrapa (54) were second, sixth and seventh, respectively, more productive centers. Brazil is the second in number of articles. Considered all journal in which at least one article was published about beef cattle breeding, the observed mean impact factor was 1.75 (±1.75). Angus was the most cited bovine breed and the main research objective in animal breeding was Genetic with 596 articles, whereas the most studied genes were CAPN1 and CAST, used in 62% of all articles found, and the most used molecular markers was SNPs, found in 70% of the articles. Based on scientometrical analysis, we observed that the scientific production about cattle breeding is according to beef cattle market, wherein countries like United States and Brazil highlights. Other studies using meta-analysis, for example, should be done to confirm data obtained in this work. / O objetivo desse estudo foi avaliar a produção científica em melhoramento genético de bovinos de corte nos últimos 48 anos (1964-2012). O levantamento dos estudos foi realizado por meio do banco de dados SCOPUS, utilizando as palavras-chave beef* cattle* and breeding* . Foram selecionadas as publicações que apresentaram informações, tais como: ano de publicação do artigo, período em que o artigo foi publicado, nacionalidade do primeiro autor, tipo de documento; área científica da publicação, filiação dos autores. Foram encontrados 1946 trabalhos publicados entre os anos de 1964 e 2012. Foi observado um aumento expressivo no número de trabalhos na área de melhoramento genético no final da década de 1980, sendo mais acentuado depois de 2004. Dentre os 1946 trabalhos, 1.717 foram artigos originais. Dos 160 autores diferentes que mais publicaram 21 deles perfazem juntos 30% das publicações. A área científica que mais publicou foi Ciências Agrárias e Biológicas (55%). Na avaliação dos periódicos a Journal of Animal Science apareceu em primeiro lugar com 696 artigos, sendo que a Revista Brasileira de Zootecnia aparece em quarto lugar com 50 artigos. Quanto a filiação institucional, a USDA (75) aparece em primeiro lugar, seguida da UNESP (72), USP (54) e Embrapa (54) ficaram em sexto e sétimo lugar, respectivamente. O Brasil é o segundo país em número de publicações. Quanto ao fator de Impacto médio das revistas foi 1,75 (±1,75). As raças bovinas mais citadas foram as do grupo taurino, destacando-se a raça Angus em primeiro lugar. Os principais objetivos dos estudos na área de melhoramento genético foram a Genética com 596 artigos. Os genes mais estudados foram CAPN1 e CAST perfazendo juntos 62%, e os marcadores moleculares mais usados nos estudos foram os SNPs em 70% dos artigos. A análise cienciométrica permitiu observar que os dados da produção científica em melhoramento genético de bovinos estão de acordo com o que se observa no mercado da bovinocultura de corte, aonde se destacam países como, Estados Unidos e Brasil.

Resumo: Este estudo avaliou o efeito dos níveis de energia (NDT) e proteína bruta (PB) consumidos por vacas de corte durante a gestação sobre o peso dos fetos aos quatro (PF4) e oito meses (PF8) e dos bezerros ao nascimento (PN); sobre o peso pós-natal aos 60 (PV60), 100 (PV100), 180 (PV180) e 205 (PV205) dias de vida; sobre o peso, a idade, o ganho médio diário (GMD), a área de olho de lombo (AOL), o marmoreio e a espessura de gordura (EG) ao abate. Foi conduzida uma revisão sistemática da literatura e uma metanálise (MA) a partir de duas bases de dados eletrônicas (Scopus e Web of Science). A MA para efeitos randomizados foi realizada para cada resultado com as médias do grupo controle e tratado, conduzida com os níveis de NDT e PB em relação às exigências das vacas (NRC, 1996). Foram avaliadas 46 publicações, correspondentes a 50 estudos, 135 ensaios e 9.379 animais. Não houve efeito do consumo de PB e NDT pelas vacas sobre o PF4. Quando as vacas consumiram PB e NDT em níveis iguais às suas exigências, no primeiro (1TRI) e segundo trimestre (2TRI) da gestação, houve redução no PF8 (DM= 2,236kg; P<0,001). O PN reduziu nos bezerros filhos de vacas que consumiram PB igual ou acima das suas exigências no terceiro trimestre da gestação (3TRI) (DM= -2,954kg; P<0,001 e DM= -0,453kg; P=0,045, respectivamente) ou 140% das exigências de NDT (DM= -2,709; P = 0,001). Quando o consumo de NDT foi igual à recomendação do NRC (1996), observou-se aumento de 2,029kg no PN dos bezerros (P<0,001). O PV60 foi inferior quando as vacas consumiram PB (DM= -1,923kg; P<0,001) e NDT (DM= -1,676kg; P<0,001) acima de suas exigências no 3TRI. O PV205 foi 3,122kg inferior (P<0,001) quando as vacas consumiram até 120% de NDT no 2TRI e 3TRI. Os novilhos cujas mães consumiram PB e NDT acima de suas demandas, no 3TRI, foram abatidos 5,5 dias antes (P= 0,015) que os demais. O GMD, o marmoreio e a EG foram superiores em vacas que consumiram NDT e PB acima das suas exigências no 3TRI (P<0,05). Em síntese, os níveis de PB e NDT, consumidos pelas vacas, acima das recomendações do NRC, estão negativamente relacionados com o desenvolvimento dos fetos e com o PN, sendo que esse efeito permanece até os 205 dias de idade. Por outro lado, na fase de terminação o excesso de PB e NDT passa a contribuir com o GMD, o marmoreio e a EG da carcaça das progênies. / Abstract: This study evaluated the effect of total digestible nutrients (TDN) and crude protein (CP) levels, consumed by cows during gestation, on fetal and postnatal development and on carcass traits. We conducted a systematic review of the literature and a metanalysis (MA) on two electronic databases (Scopus and Web of Science). Inclusion criteria were complete studies using pregnant beef cows receiving different diets that analysed fetus weight at four (FW4) and eight months (FW8), and birth weight of calves (BW); postnatal weight at 60 days (PW60), 100 days (PW100), 180 days (PW180) and 205 days (PW205) of life; and on weight, age, mean daily gain (ADG), loin eye area (LEA), marbling and fat thickness (FT) at slaughter. Random effect MA were conducted for each indicator separately with the mean of control and treated group. The analysis was conducted with the TDN and CP levels in relation to cows’ requirements (NRC, 1996). We evaluated 46 publications, reporting 50 studies, 135 trials and 9,379 animals. The CP and TDN level consumed by pregnant cows showed no change on FW4. Cows that consumed CP and TDN in a level equal to their requirements, in the first (1TRI) and second trimester (2TRI) of gestation, showed a reduction in FW8 (DM= 2,236kg; P<0.001). The BW reduced in cows that consumed CP equal to or above their requirements in the third trimester of gestation (3TRI) (DM= -2.954kg, P<0.001 and DM= -0,453kg, P=0.045, respectively), or 140% of TDN requirements (DM= -2.709, P=0.001). The calves of cows that consumed TDN equal to NRC (1996) requirements, increased the BW in 2,029kg (P<0.001). The PW60 was lower when cows consumed CP (DM= -1.923kg; P<0.001) and TDN (DM= -1.676kg; P<0.001) above their requirements in the 3TRI. The PW205 was lower (DM= 3.12kg; P<0.001) when cows consumed 120% of TDN in the 2TRI and 3TRI. Steers whose mothers consumed CP and TDN above their requirements in the 3TRI were slaughtered 5.5 days earlier (P= 0.015) than the others. The ADG, marbling and FT were higher when cows consumed TDN and CP above the NRC (1996) requirements in the 3TRI (P<0.05). In summary, the CP and TDN levels, consumed by cows, above the NRC recommendations, are negatively associated to fetal development and birth calf weight, and this effect remains until 205 days of age. Alternatively, in the feeder phase, CP and TDN in excess contribute to average daily gain, marbling and fat thickness of the progeny.

Resumo: Este estudo avaliou o efeito dos níveis de energia (NDT) e proteína bruta (PB) consumidos por vacas de corte durante a gestação sobre o peso dos fetos aos quatro (PF4) e oito meses (PF8) e dos bezerros ao nascimento (PN); sobre o peso pós-natal aos 60 (PV60), 100 (PV100), 180 (PV180) e 205 (PV205) dias de vida; sobre o peso, a idade, o ganho médio diário (GMD), a área de olho de lombo (AOL), o marmoreio e a espessura de gordura (EG) ao abate. Foi conduzida uma revisão sistemática da literatura e uma metanálise (MA) a partir de duas bases de dados eletrônicas (Scopus e Web of Science). A MA para efeitos randomizados foi realizada para cada resultado com as médias do grupo controle e tratado, conduzida com os níveis de NDT e PB em relação às exigências das vacas (NRC, 1996). Foram avaliadas 46 publicações, correspondentes a 50 estudos, 135 ensaios e 9.379 animais. Não houve efeito do consumo de PB e NDT pelas vacas sobre o PF4. Quando as vacas consumiram PB e NDT em níveis iguais às suas exigências, no primeiro (1TRI) e segundo trimestre (2TRI) da gestação, houve redução no PF8 (DM= 2,236kg; P<0,001). O PN reduziu nos bezerros filhos de vacas que consumiram PB igual ou acima das suas exigências no terceiro trimestre da gestação (3TRI) (DM= -2,954kg; P<0,001 e DM= -0,453kg; P=0,045, respectivamente) ou 140% das exigências de NDT (DM= -2,709; P = 0,001). Quando o consumo de NDT foi igual à recomendação do NRC (1996), observou-se aumento de 2,029kg no PN dos bezerros (P<0,001). O PV60 foi inferior quando as vacas consumiram PB (DM= -1,923kg; P<0,001) e NDT (DM= -1,676kg; P<0,001) acima de suas exigências no 3TRI. O PV205 foi 3,122kg inferior (P<0,001) quando as vacas consumiram até 120% de NDT no 2TRI e 3TRI. Os novilhos cujas mães consumiram PB e NDT acima de suas demandas, no 3TRI, foram abatidos 5,5 dias antes (P= 0,015) que os demais. O GMD, o marmoreio e a EG foram superiores em vacas que consumiram NDT e PB acima das suas exigências no 3TRI (P<0,05). Em síntese, os níveis de PB e NDT, consumidos pelas vacas, acima das recomendações do NRC, estão negativamente relacionados com o desenvolvimento dos fetos e com o PN, sendo que esse efeito permanece até os 205 dias de idade. Por outro lado, na fase de terminação o excesso de PB e NDT passa a contribuir com o GMD, o marmoreio e a EG da carcaça das progênies. / Abstract: This study evaluated the effect of total digestible nutrients (TDN) and crude protein (CP) levels, consumed by cows during gestation, on fetal and postnatal development and on carcass traits. We conducted a systematic review of the literature and a metanalysis (MA) on two electronic databases (Scopus and Web of Science). Inclusion criteria were complete studies using pregnant beef cows receiving different diets that analysed fetus weight at four (FW4) and eight months (FW8), and birth weight of calves (BW); postnatal weight at 60 days (PW60), 100 days (PW100), 180 days (PW180) and 205 days (PW205) of life; and on weight, age, mean daily gain (ADG), loin eye area (LEA), marbling and fat thickness (FT) at slaughter. Random effect MA were conducted for each indicator separately with the mean of control and treated group. The analysis was conducted with the TDN and CP levels in relation to cows’ requirements (NRC, 1996). We evaluated 46 publications, reporting 50 studies, 135 trials and 9,379 animals. The CP and TDN level consumed by pregnant cows showed no change on FW4. Cows that consumed CP and TDN in a level equal to their requirements, in the first (1TRI) and second trimester (2TRI) of gestation, showed a reduction in FW8 (DM= 2,236kg; P<0.001). The BW reduced in cows that consumed CP equal to or above their requirements in the third trimester of gestation (3TRI) (DM= -2.954kg, P<0.001 and DM= -0,453kg, P=0.045, respectively), or 140% of TDN requirements (DM= -2.709, P=0.001). The calves of cows that consumed TDN equal to NRC (1996) requirements, increased the BW in 2,029kg (P<0.001). The PW60 was lower when cows consumed CP (DM= -1.923kg; P<0.001) and TDN (DM= -1.676kg; P<0.001) above their requirements in the 3TRI. The PW205 was lower (DM= 3.12kg; P<0.001) when cows consumed 120% of TDN in the 2TRI and 3TRI. Steers whose mothers consumed CP and TDN above their requirements in the 3TRI were slaughtered 5.5 days earlier (P= 0.015) than the others. The ADG, marbling and FT were higher when cows consumed TDN and CP above the NRC (1996) requirements in the 3TRI (P<0.05). In summary, the CP and TDN levels, consumed by cows, above the NRC recommendations, are negatively associated to fetal development and birth calf weight, and this effect remains until 205 days of age. Alternatively, in the feeder phase, CP and TDN in excess contribute to average daily gain, marbling and fat thickness of the progeny.