O objetivo dessa pesquisa foi avaliar os parâmetros genéticos e correlações das medidas de ingestão e eficiência alimentar com desempenho e características de carcaça, além de realizar o estudo de associação de amplo genoma (GWAS) para ingestão de matéria seca (IMS), consumo alimentar residual (CAR) e ganho de peso (GMD) em bovinos da raça Nelore (Bos indicus). Foram utilizados dados de 1.058 animais com fenótipo para IMS, taxa de conversão alimentar (CA), CAR, ganho de peso residual (GPR), consumo e ganho residuais (CGR), ganho de peso diário (GMD) e características de carcaça. Os parâmetros genéticos da IMS, CA, CAR, GPR e CGR e suas as correlações com GMD e características de carcaça foram estimados utilizando abordagem bayesiana. Quatro marcadores do tipo SNP (Single Nucleotide Polymorphism), localizados em genes relacionados ao controle de apetite (NPY e PDE3B) e transporte iônico (TRPM3 e ITPR1), foram associados com o desempenho, ingestão e medidas de eficiência alimentar. Adicionalmente, os animais foram genotipados em dois chips distintos (Illumina Bovine HD e Illumina BovineSNP50) e as informações genotípicas foram combinadas por meio de estudo de imputação. As centenas de milhares de SNPs foram utilizadas para o GWAS da IMS, CAR e GMD pelo teste de associação GRAMMAR-Gamma. A herdabilidade da IMS, CAR e CGR foi de 0,40, 0,38 e 0,54, respectivamente. Não foram encontradas associações nos SNPs localizados nos genes TRPM3, NPY e ITPR1, no entanto, o SNP no gene PDE3B foi associados significativamente (P≤0,05) com IMS, CAR e CGR. Os SNPs mais associados com a IMS e CAR, no GWAS, estão localizados nos cromossomos 4, 8, 14 e 21 em regiões genômicas relacionadas com transporte iônico e regulação da ingestão. O GWAS para o GMD apontou os cromossomos 3, 6 e 10 como os que continham os marcadores com maior associação. A ingestão e eficiência alimentar são passíveis de seleção genética, principalmente o CGR. O gene PDE3B deve ser melhor estudado pois, aparenta ter relação com esses fenótipos. Por fim, esse trabalho apontou regiões genômicas, por meio de associação de amplo genoma, relacionadas com a IMS, CAR e GMD, acredita-se ser o primeiro estudo desse tipo para esses fenótipos em animais da raça Nelore. / The aim of this study was to evaluate the genetic parameters and correlations of intake and feed efficiency with performance and carcass traits, and perform the genome-wide association study (GWAS) for dry matter intake (DMI), residual feed intake (RFI) and average daily gain (ADG) in Nelore cattle (Bos indicus). Data from 1,058 animals phenotyped for DMI, feed conversion ratio (FCR), RFI, residual body weight gain (RG), residual intake and body weight gain (RIG), average daily gain (ADG) and carcass traits were used. Genetic parameters of DMI, FCR, RFI, RG and RIG and their correlations with ADG and carcass traits were estimated using Bayesian approach. Four SNPs (Single Nucleotide Polymorphism), located in genes related to appetite control (NPY and PDE3B) and ion transport (TRPM3 and ITPR1), were associated with performance, intake and feed efficiency traits. Additionally, the animals were genotyped in two different chips (Illumina Bovine HD and Illumina BovineSNP50) and genotypic information were combined by imputation. The hundreds of thousands of SNPs were used for GWAS of DMI, RFI and ADG by GRAMMAR-Gamma association test. The heritability of DMI, RFI and RIG was 0.40, 0.38 and 0.54, respectively. No associations were found in SNPs in genes TRPM3, NPY and ITPR1, however, the SNP in PDE3B gene was significantly associated (P≤0.05) with DMI, RFI and RIG. The SNPs most associated with DMI and RFI, in GWAS, are located on chromosomes 4, 8, 14 and 21 in genomic regions associated with ion transport and appetite regulation. The GWAS pointed chromosomes 3, 6 and 10 as those containing more associated markers for ADG. Feed intake and feed efficiency are amenable to genetic selection, especially the RIG. The PDE3B gene should be further studied thus appears to be related to these phenotypes. Finally, this work shows genomic regions by genome-wide association, related to DMI, RFI and ADG, believed to be the first study of its kind for these phenotypes in Nellore cattle.

O interesse quanto ao uso de índices de eficiência alimentar na seleção de bovinos é crescente, pela sua associação com o custo de produção e impacto ambiental. O objetivo deste trabalho foi avaliar dois índices de eficiência, o consumo alimentar residual (CAR) e consumo e ganho residual (CGR) e suas relações com desempenho, características de carcaça, qualidade de carne, batimentos cardíacos e consumo de oxigênio em bovinos Nelore. Foram avaliados 84 animais para desempenho, peso de carcaça, rendimento, área de olho de lombo, espessura de gordura subcutânea, peso de vísceras e gordura interna. Foi avaliada a qualidade da carne de amostras não maturadas e maturadas (pH, força de cisalhamento, cor, perdas por cocção, capacidade de retenção de água, índice de fragmentação miofibrilar e gordura intramuscular). Para estimar a produção de calor (PC) pela metodologia do Pulso de O2 (O2P), 39 animais foram monitorados para frequência cardíaca, que foi calibrada para consumo de O2 em 18 deles. A PC foi estimada multiplicando-se o total de batimentos cardíacos diários pelo volume de O2/batimento e pela constante 4,89 kcal/LO2. Foram estudados os coeficientes de inclinação das retas entre CAR e CGR e as variáveis estudadas. O CAR não foi associado com o peso vivo e ganho de peso (P>0,05), porém animais eficientes consumiram 16,1% menos alimento (P<0,0001). Animais eficientes para CGR apresentaram consumo 11,7% menor e ganharam mais peso (P<0,01). O CGR não foi associado ao peso vivo metabólico médio (P>0,05), contudo foi associado ao peso vivo final (P=0,06). A PC estimada pela diferença entre energia retida e consumo de energia metabolizável foi maior nos animais ineficientes (P<0,0001), porém não foi diferente quando estimada pela metodologia do O2P (P>0,05). A frequência cardíaca (FC) e consumo de O2 não foram associados ao CAR e CGR (P>0,05), contudo a FC foi menor nos animais eficientes durante a calibração do O2 (P<0,05). Ambos os índices foram associados com mudanças na composição corporal; animais eficientes para CAR apresentaram menor teor de gordura subcutânea avaliada por ultrassom (P=0,08), e os eficientes para CGR apresentaram maior AOL (P<0,05). As características de qualidade da carne não foram associadas ao CAR, mas animais eficientes para CGR apresentaram intensidade da cor vermelha na carne menor e na gordura maior (P<0,05). Animais eficientes quanto ao CAR apresentaram menor peso de fígado e de gordura interna (P<0,05) sendo este efeito não observado para CGR. Os animais eficientes em ambos, CAR e CGR, apresentaram menor custo de produção resultando em aumento no lucro (P<0,01). O lucro foi fortemente associado à conversão alimentar, CGR e ganho de peso (r=-0,812; 0,72 e 0,61; P<0,0001) enquanto sua associação com CAR foi menor (r=-0,46; P<0,0001). As correlações fenotípicas sugerem que seleção de animais eficientes para CAR ou CGR pode reduzir custos na produção de bovinos de corte, com alteração na coloração da carne. O lucro tem maior correlação com o CGR que com CAR. Porém o CGR tem a possível desvantagem de ser fenotipicamente associado ao maior peso final o que pode indicar uma correlação genética para peso adulto. / There is growing interest in the use of feed efficiency in beef cattle, due to its relationship to production costs and environmental impact. Identification of variation in energy losses can explain differences in efficiency. The objective of this study was to evaluate measures of feed efficiency (residual feed intake - RFI and residual intake and gain _ RIG) and their relationships with performance, carcass characteristics, meat quality, heart rate and oxygen use in Nellore bulls. A group of 84 animals were evaluated for performance, carcass characteristics (weight, yield, loin eye area, fat thickness, weight of visceral and internal fat) and meat quality in fresh and aged meat samples (pH, shear force, cooking loss, water retention capacity, myofibrilar fragmentation index and intramuscular fat). To estimate heat production (HP) by O2 pulse methodology (O2P), 39 animals were monitored for heart rate (HR). A subgroup of 18 animals which was calibrated for O2 consumption determined over in 18 of them. HP was estimated multiplying daily heart beats by O2 volume per beat, assuming 4.89 kcal/LO2 as constant. The slope coefficient for each variable against RFI and RIG was studied. There was no association of RFI with weight (P>0.05) and weight gain (P>0.05), but efficient animals consumed 16.1% less feed (P<0.0001). Efficient animals for RIG consumed 11.7% less food (P<0.0001), but gained more weight than inefficient animals (P<0.01). There was no association between RIG and average metabolic weight (P>0.05), however RIG was related to final weight (P=0.06). HP estimated by the difference between retained energy and metabolic energy intake was higher for inefficient animals (P<0.001), for both RFI and RIG. However there was no effect on HP estimated by the O2P methodology (P>0.05). Heart rate (HR) and O2 consumption were not associated with RFI and RIG (P>0.05), but HR was lower in efficient animals during O2 calibration (P<0.05). There was a positive association of efficiency with a leaner gain composition, where efficient animals for RFI had of lower ultrasound subcutaneous fat (P=0.08), while efficient animals for RIG had higher loin eye area (P<0.05). There was no effect on meat quality parameters for RFI but in efficient animals for RIG, there was an effect on meat and fat color (P<0.05) compared to inefficient animals. Internal fat and liver weights were decreased in efficient animals according to RFI (P<0.05), but unchanged according to RIG (P>0.05). Efficient animals for RFI and RIG had lower cost of production resulting in increased profit (P<0.01). Profit was strongly associated with feed intake, RIG and weight gain (r =-0.81, 0.72 and 0.61, P<0.0001), whereas its association with RFI was lower (r =-0.46, P<0.0001). Efficient animals for RFI and RIG are more profitable with small decreases in fat and small increases in muscle content. Profit is better related to RIG than RFI. However, RIG had the disadvantage of increasing final test weight which could be genetically associated with mature weight.

O interesse quanto ao uso de índices de eficiência alimentar na seleção de bovinos é crescente, pela sua associação com o custo de produção e impacto ambiental. O objetivo deste trabalho foi avaliar dois índices de eficiência, o consumo alimentar residual (CAR) e consumo e ganho residual (CGR) e suas relações com desempenho, características de carcaça, qualidade de carne, batimentos cardíacos e consumo de oxigênio em bovinos Nelore. Foram avaliados 84 animais para desempenho, peso de carcaça, rendimento, área de olho de lombo, espessura de gordura subcutânea, peso de vísceras e gordura interna. Foi avaliada a qualidade da carne de amostras não maturadas e maturadas (pH, força de cisalhamento, cor, perdas por cocção, capacidade de retenção de água, índice de fragmentação miofibrilar e gordura intramuscular). Para estimar a produção de calor (PC) pela metodologia do Pulso de O2 (O2P), 39 animais foram monitorados para frequência cardíaca, que foi calibrada para consumo de O2 em 18 deles. A PC foi estimada multiplicando-se o total de batimentos cardíacos diários pelo volume de O2/batimento e pela constante 4,89 kcal/LO2. Foram estudados os coeficientes de inclinação das retas entre CAR e CGR e as variáveis estudadas. O CAR não foi associado com o peso vivo e ganho de peso (P>0,05), porém animais eficientes consumiram 16,1% menos alimento (P<0,0001). Animais eficientes para CGR apresentaram consumo 11,7% menor e ganharam mais peso (P<0,01). O CGR não foi associado ao peso vivo metabólico médio (P>0,05), contudo foi associado ao peso vivo final (P=0,06). A PC estimada pela diferença entre energia retida e consumo de energia metabolizável foi maior nos animais ineficientes (P<0,0001), porém não foi diferente quando estimada pela metodologia do O2P (P>0,05). A frequência cardíaca (FC) e consumo de O2 não foram associados ao CAR e CGR (P>0,05), contudo a FC foi menor nos animais eficientes durante a calibração do O2 (P<0,05). Ambos os índices foram associados com mudanças na composição corporal; animais eficientes para CAR apresentaram menor teor de gordura subcutânea avaliada por ultrassom (P=0,08), e os eficientes para CGR apresentaram maior AOL (P<0,05). As características de qualidade da carne não foram associadas ao CAR, mas animais eficientes para CGR apresentaram intensidade da cor vermelha na carne menor e na gordura maior (P<0,05). Animais eficientes quanto ao CAR apresentaram menor peso de fígado e de gordura interna (P<0,05) sendo este efeito não observado para CGR. Os animais eficientes em ambos, CAR e CGR, apresentaram menor custo de produção resultando em aumento no lucro (P<0,01). O lucro foi fortemente associado à conversão alimentar, CGR e ganho de peso (r=-0,812; 0,72 e 0,61; P<0,0001) enquanto sua associação com CAR foi menor (r=-0,46; P<0,0001). As correlações fenotípicas sugerem que seleção de animais eficientes para CAR ou CGR pode reduzir custos na produção de bovinos de corte, com alteração na coloração da carne. O lucro tem maior correlação com o CGR que com CAR. Porém o CGR tem a possível desvantagem de ser fenotipicamente associado ao maior peso final o que pode indicar uma correlação genética para peso adulto. / There is growing interest in the use of feed efficiency in beef cattle, due to its relationship to production costs and environmental impact. Identification of variation in energy losses can explain differences in efficiency. The objective of this study was to evaluate measures of feed efficiency (residual feed intake - RFI and residual intake and gain _ RIG) and their relationships with performance, carcass characteristics, meat quality, heart rate and oxygen use in Nellore bulls. A group of 84 animals were evaluated for performance, carcass characteristics (weight, yield, loin eye area, fat thickness, weight of visceral and internal fat) and meat quality in fresh and aged meat samples (pH, shear force, cooking loss, water retention capacity, myofibrilar fragmentation index and intramuscular fat). To estimate heat production (HP) by O2 pulse methodology (O2P), 39 animals were monitored for heart rate (HR). A subgroup of 18 animals which was calibrated for O2 consumption determined over in 18 of them. HP was estimated multiplying daily heart beats by O2 volume per beat, assuming 4.89 kcal/LO2 as constant. The slope coefficient for each variable against RFI and RIG was studied. There was no association of RFI with weight (P>0.05) and weight gain (P>0.05), but efficient animals consumed 16.1% less feed (P<0.0001). Efficient animals for RIG consumed 11.7% less food (P<0.0001), but gained more weight than inefficient animals (P<0.01). There was no association between RIG and average metabolic weight (P>0.05), however RIG was related to final weight (P=0.06). HP estimated by the difference between retained energy and metabolic energy intake was higher for inefficient animals (P<0.001), for both RFI and RIG. However there was no effect on HP estimated by the O2P methodology (P>0.05). Heart rate (HR) and O2 consumption were not associated with RFI and RIG (P>0.05), but HR was lower in efficient animals during O2 calibration (P<0.05). There was a positive association of efficiency with a leaner gain composition, where efficient animals for RFI had of lower ultrasound subcutaneous fat (P=0.08), while efficient animals for RIG had higher loin eye area (P<0.05). There was no effect on meat quality parameters for RFI but in efficient animals for RIG, there was an effect on meat and fat color (P<0.05) compared to inefficient animals. Internal fat and liver weights were decreased in efficient animals according to RFI (P<0.05), but unchanged according to RIG (P>0.05). Efficient animals for RFI and RIG had lower cost of production resulting in increased profit (P<0.01). Profit was strongly associated with feed intake, RIG and weight gain (r =-0.81, 0.72 and 0.61, P<0.0001), whereas its association with RFI was lower (r =-0.46, P<0.0001). Efficient animals for RFI and RIG are more profitable with small decreases in fat and small increases in muscle content. Profit is better related to RIG than RFI. However, RIG had the disadvantage of increasing final test weight which could be genetically associated with mature weight.

ABSTRACT: Study One - Our objective was to characterize mature range cows based on intake and grazing activity. Starting in the early spring of 2013, 4 experiments were conducted. First, mature range cows (n = 137) were fitted with radio frequency identification tags (RFID) and placed in a dry-lot pen equipped with GrowSafe® technology to monitor DMI of alfalfa hay. These data were then used to assign cows a residual feed intake (RFI) value utilizing the National Research Council (NRC) (1996) model to predict intake of beef cattle. Cattle with negative and positive RFI were characterized as low-intake and high-intake, respectively. In addition, the following data were also recorded: weight (kg), age (mo), days pregnant (d), and body condition score (BCS). Second, 30 mature range cattle were selected from the first trial and fitted with pedometers for 7 d to monitor activity with step counts and estimate distance traveled. Third, mature range cows (n = 25) selected from the first trial were fitted with global position system (GPS) collars, and placed on pinyon-juniper rangeland from 20 June 2014 to 17 September 2014. Forth, mature range cows (n = 28) were fitted with GPS collars, and placed on ponderosa pine rangeland from 17 September 2014 to 15 October 2014. Distance traveled, slope, distance from water, elevation data were collected from both GPS trials. Low-intake and high-intake cows consumed 9.3 and 12.2 kg/d, respectively (P < 0.0001). Low-intake cattle became pregnant sooner (P = 0.002) than high-intake cattle (average of 16 d sooner). Cattle age (mo) equaled 90 and 98 for low- and high-intake cows, respectively (P = 0.04). Weight, predicted DMI, and BCS did not differ between groups (P > 0.06). Step counts for low- and high-intake animals were 5839 and 5383 ± 2089, respectively (P = 0.61), and estimated distance traveled was 4.31 and 5.35 ± 1.66 km d⁻¹ for low- and high-intake animals, respectively (P = 0.77). Low-intake cows (6.23 km d⁻¹) traveled farther (P = 0.005) each day than high-intake cows (5.84 km d⁻¹) on pinyon-juniper rangelands, and high-intake cows utilized (P = 0.013) steeper slopes. No differences were detected (P ≥ 0.06) for distance traveled, distance from water, and elevation for cows grazing ponderosa pine rangeland). However, low-intake cattle preferred (P = 0.046) steeper slopes on ponderosa pine rangeland than high-intake cattle. These results indicate that low-intake animals may travel farther on some rangelands and rebreed earlier. Study Two - Commercial grade heifers (n = 173) born and raised on the University of Arizona's V bar V Ranch from 2012 to 2014 were fitted with radio frequency identification tags (RFID) and placed in a drylot equipped with Growsafe® technology (8 bunks) for 60 d in 3 groups based on birth year in order to calculate DMI, residual feed intake (RFI), ADG, G:F, and residual gain (RG). Birth date, birth weight, weaning weight, age at start of trial, initial trial weight, and final trial weights were also recorded. Residual feed intake scores were utilized to place heifers in one of three treatment groups, low-, medium-, and high-intake. Reproductive and calf data were collected on heifers born in 2012. Means for birth date, birth weight, weaning weight, initial weight, final weight, and ADG did not differ among the three treatments. Residual gain for low-, medium-, and high-intake heifers were different (P < 0.05) at 0.07, 0.00, and -0.07 kg d⁻¹, respectively. Low-intake cattle had an improved (P < 0.05) GF ratio of 0.19 when compared to the medium- and high-intake heifers with ratios of 0.15 and 0.13 (P > 0.05), respectively. Differences (P <0. 05) in DMI were detected with low-, medium, and high-intake heifers consuming 5.2, 6.2, and 7.5 kg d⁻¹, respectively. No differences were detected for pregnancy rate, calving rate, percent bred artificial insemination (AI), percent bull calves, calf birth weight, and calf birth date among treatments (P > 0.05).Study Three - Commercially available GPS tracking collars for cattle are cost prohibitive to most researchers. This paper will present a low-cost alternative to those collars (Knight GPS tracking collars), and provide detailed instructions on where to source materials and how to fabricate inexpensive GPS tracking collars. In addition, the two types of collars will be compared in a study where Brangus cattle (n = 8) were each fitted with LOTEK® 3300 and Knight GPS tracking collars for 31 d beginning 14 March 2015 at the Chihuahuan Desert Rangeland Research Center (CDRRC) 37 km north of Las Cruces, New Mexico. Location, slope, distance from water, distance traveled and elevation were recorded every 10 min. A record of GPS fix rate was logged. No differences were detected (P≥0.369) between collar types for location, slope, or distance from water. However, there was a tendency (P = 0.08) for Knight collars to report a lower estimate for distance traveled at 6171 m d⁻¹ compared to Lotek collars at 7104 m d⁻¹. Fix rate was greater (P≤0.001) for Lotek collars compared to Knight collars at 99.9 and 66.2%, respectively. Study Four - Previously characterized commercial cows (n = 26) were placed into either high (positive RFI) or low intake (negative RFI) groups. On 14 May 2015, 13 high- and 13 low-intake cows were fitted with modified igotU GT-120® GPS logging collars. Cattle were then placed on rangeland for 120 d. The first 30 d period animals transitioned from desert shrubland to pinyon-juniper. From 31 to 60 d, animals grazed pinyon-juniper rangeland. Next, during days 61 to 90, animals transitioned from pinyon-juniper to ponderosa pine, and the last 30 d were spent in ponderosa pine. Time periods will be referred to as month 1, 2, 3, and 4 for days 0 to 30, 31 to 60, 61 to 90, and 91 to 120, respectively. Location, slope, distance from water, elevation, and time spent close to water were recorded every 10 min. No differences were observed in the utilization of elevation or distance traveled, or distance from water (P>0.05). Low intake animals used a higher maximum slope (P < 0.05) during month 3, but slope utilization differences were not detected for other portions of the trial (P > 0.05). Study Five - Hereford sires (n = 35) with 7 or more cow offspring on the University of Arizona V bar V ranch in Rimrock, Arizona were tested at Neogen laboratories in Lincoln, NE for an Igenity Gold genetic profile. Their residual feed intake (RFI), ADG, tenderness, marbling score, milk production percent choice, yield grade, fat thickness, ribeye area, heifer pregnancy rate, stayability, maternal calving ease, birthweight and docility were estimated. Sires were given a genetic RFI score based on their RFI profile and placed into one of three intake groups, low (< 0.5 SD), medium (± 0.5 SD) and high (> 0.5 SD). Performance traits of cow offspring (n = 839) from those sires were also compared based on their sire's intake group. No differences (P > 0.05) were detected among sire intake groups for ADG, tenderness, marbling score, percent choice, yield grade, fat thickness, ribeye area, heifer pregnancy rate, stayability, maternal calving ease, birthweight and docility. Residual feed intake differed among groups (P < 0.05), and high intake cattle had more estimated milk production compared to low intake animals (P < 0.05). Cows from low intake sires were born later in the year (P < 0.05). High intake cattle had a higher (P < 0.05) birthweight and survived longer (P < 0.05) in the herd when compared to low and medium intake cows. Genetic RFI and expected milk production were moderately to highly correlated.

Residual Feed Intake (RFI) and enteric methane (CH4) emissions were measured over two years on 120 Angus bulls receiving either a silage-hay diet or a silage-grain diet (277±28 and 286±25 d of age in year 1; 249±23 and 250±23 d of age in year 2). Emissions were similar between diets (240 vs. 248  7.9 L d-1, P>0.05; silage-hay vs. silage-grain) and RFI grouping (P>0.05). DMI increased for high RFI bulls versus low RFI bulls (7.68±0.2 and 8.24±0.2 kg DM d-1, low vs. high). Correlations between RFIfat and CH4 emissions were not significant. These findings agree with previous studies and suggest that RFI ranking may be associated with metabolic mechanisms other than fermentation efficiency. / October 2016

Master of Science / Department of Animal Sciences and Industry / Jennifer M. Bormann / It is important for animals to be feed efficient and reproductively sound to optimize profits for cow- calf producers. The objective of this study was to determine the relationship between feed efficiency and reproductive performance. Feed efficiency measures included residual feed intake (RFI), feed to gain ratio (F:G) and daily dry matter intake (DMI). Reproductive measurements were pregnancy rate, first service conception rate, pregnancy type (AI, natural. open), calving percentage, calving day (CD) and age at first calving. Two data sets which included 136 crossbred Angus females sired by bulls with high or low RFI estimated breeding values (EBV) with multiple parity information and 56 purebred Hereford heifers with their first parity calving information were analyzed. Initially, the crossbred Angus females were analyzed based on their phenotypic RFI values. There was no difference in pregnancy rate between the feed efficiency measures. Second parity pregnant females had lower (F:G) with first service conception (P=0.053), and pregnancy types (P=0.014) than the open (less efficient) females. In parity 5, phenotypically efficient RFI Angus females were pregnant to first service conception versus inefficient RFI Angus females (P=0.052) and those with lower DMI were diagnosed pregnant (P=0.0002). When evaluated as a repeated trait, RFI was not a significant indicator of CD (P=0.514). Crossbred Angus females were analyzed based on their sire’s RFI EBV and grouped accordingly into high (inefficient) or low (efficient) RFI sires. Females sired by high or low RFI (EBV) bulls showed no difference for the reproductive traits, except for a tendency for inefficient sired heifers to have a lower calving percentage in parity 2 (P=0.048). When CD was analyzed as a repeated measure, no difference between sire groups was found (efficient CD of 35.64 d, inefficient CD of 34.23, p = 0.789). In the Hereford heifers, RFI was not an indicator of CD (P = 0.774). There was also no difference in RFI between pregnant and open Hereford females with pregnant females having an LSMean of 0.11 kg/d and the open females having an LSMean of 0.14 kg/d (P = 0.860). Further research needs to be done to confirm any relationships between feed efficiency and reproduction.

Este estudo teve como objetivo avaliar o efeito do uso de dois beta-agonistas adrenérgicos (&beta;AA), cloridrato de zilpaterol (ZIL) e cloridrato de ractopamina (RAC), em combinação com a técnica de imunocastração sobre o desempenho, perfil sanguíneo, comportamento ingestivo e características de carcaça de bovinos confinados na fase de terminação. Noventa e seis bovinos machos da raça Nelore, com peso vivo inicial médio de 409 kg &plusmn; 50 kg e idade média de 20 meses, foram divididos em dois grupos de 48 animais, no qual metade dos animais de cada grupo recebeu a vacina de imunocastração enquanto que a outra metade não recebeu a vacina. Os animais foram alimentados por 70 dias com uma dieta comum contendo 76% de concentrado e 24% de volumoso (silagem de milho). Após 70 dias de confinamento, os animais foram divididos em três grupos, de acordo com o peso, dentro de cada bloco e condição sexual, e aleatoriamente alimentados com uma das seguintes dietas, pelos 30 dias seguintes: CON - dieta padrão utilizada na fase anterior, sem a adição de &beta;AA; ZIL - dieta padrão acrescida de 80 mg/dia cloridrato de zilpaterol; RAC - dieta padrão acrescida de 300 mg/dia cloridrato de ractopamina. Foi avaliado o desempenho, área de olho de lombo (AOL), espessura de gordura subcutânea (EGS) e espessura de gordura na picanha (EGP), bem como o comportamento ingestivo e a gasometria e o perfil bioquímico sanguíneo. No abate foi avaliado o peso vivo final (PVF), peso de carcaça quente (PCQ) e rendimento de carcaça quente (RCQ). Não houve interação entre os fatores principais para nenhuma característica avaliada. Os animais não-castrados tiveram maior ganho médio diário (GMD) e eficiência alimentar (EA) quando comparado aos animais imunocastrados, além de apresentarem maior PCQ e AOL, porém, sem alterar o RCQ, e menor EGS e EGP do que animais imunocastrados. Animais imunocastrados tiveram maior concentração sérica nas principais variáveis relacionadas ao metabolismo e deposição de gordura, tais como HDL, triglicerídeo, colesterol e ácido graxo não-esterificado. Não houve efeito dos tratamentos nem da condição sexual sobre o comportamento ingestivo dos animais. Os animais suplementados com ZIL foram superiores no GMD, EA, AOL, RCQ, porém, sem alterar o PCQ, e inferiores na EGS e EGP quando comparados a animais CON e RAC. Animais suplementados com ZIL apresentaram concentrações séricas representativas de maior metabolismo e deposição de proteína, tais como menores taxas de ureia e maiores taxas de creatino quinase. Não houve efeito da RAC sobre o CON em nenhuma das características supracitadas. A imunocastração diminui a deposição muscular e aumenta a deposição de gordura na carcaça, enquanto que os &beta;AA aumentam a proporção muscular e diminuem a proporção de gordura, havendo impacto direto no desempenho e nas características e rendimento de carcaça, sem haver interação dessas tecnologias nas características avaliadas, portanto, ambas devem ser avaliadas separadamente. / This study aimed to evaluate the effect of two beta-adrenergic agonists (&beta;AA), zilpaterol hydrochloride (ZH) and ractopamine hydrochloride (RH), in combination with immunocastrion technique on performance, blood profile, feeding behavior, and carcass traits of Nellore cattle in feedlot finishing phase. Ninety-six males Nellore cattle (409 &plusmn; 50 kg LW; 20 mo old) were divided in two groups with forty-eight animals and half of them each group received immunocastration vaccine. Animals were fed for 70 days a common diet containing 76% concentrate and 24% roughage (corn silage). Following they were split in 3 groups, according to weight and within block and sex condition, and fed 30 more days one of the following treatments: CON - basis diet without &beta;AA; ZH - basis diet plus 80mg/d zilpaterol hydrochloride; RH - basis diet plus 300mg/d of ractopamine hydrochloride. Performance, loin muscle area (LMA), backfat thickness (BFT), rump fat thickness (RFT), feeding behavior, gas blood, and blood biochemical profile were recorded in the feedlot. Final liveweight (FLW), hot carcass weight (HCW) and dressing percent (DP) were recorded in the harvest. There was no interaction between the main factors for any traits evaluated. Non-castrated animals had higher average daily gain (ADG) and feed efficiency (G:F) compared to immunocastrated animals, besides higher HCW and LMA, however, without changing DP, and lower BFT and RFT than immunocastrated animals. Immunocastrated animals showed greater serum concentration in the main variables associated to metabolism and fat deposition, such as HDL, triglycerides, cholesterol, and non-esterified fatty acid. No effect of treatments or sex condition on feeding behavior. The animals supplemented with ZH were higher in ADG, G:F, LMA, DP, however, without altering the HCW, and lower in BFT and RFT compared to CON and RH animals. ZH animals showed serum concentration representative of greater metabolism and muscle deposition, such as lower urea rates and higher creatinekinase levels. There was no effect of RH on the CON in any traits abovementioned. Immunocastration decreases the muscle deposition and increases the fat deposition in the carcass, whereas the &beta;AA increases the muscle proportion and decreases the fat proportion, which has effect on performance, carcass traits and dressing percent, with no interaction of these technologies in the characteristics evaluated, thereby both should be evaluated separately.

Objetivou-se adequar modelo de indução de acidose ruminal por ácidos graxos de cadeia curta (ARAGCC), com uso de polpa cítrica (PC), para bovinos mais pesados, assim como avaliar o metabolismo ruminal, alterações comportamentais, clínicas e diagnósticas. Para o primeiro objetivo foram utilizadas três vacas Nelore (544,2 &#177; 47 kg), com cânula ruminal, e alimentadas, duas vezes ao dia, com 75% de feno e de 25% concentrados. A dose fixa de PC (1,65% do peso vivo) administrada na cânula ruminal gerou inicialmente acidose láctica ruminal e após adequações apurou-se a fórmula (g de PC = Peso corporal 0,75 x 54,7) que provocou adequado quadro de ARAGCC (pH ruminal entre 5,8 e 5,2 com duração mínima de 5h). No 2º experimento foram empregados outros 10 animais da mesma raça, sexo e peso semelhantes, com a mesma alimentação, por no mínimo 45 dias antes da indução, acompanhando-se o consumo de matéria seca (CMS). No dia anterior à indução e nos próximos três dias foram registrados, a cada 5 min, o tempo de ruminação (TR), ingestão de alimentos (TIG) e ócio (decúbito e em estação), assim como o pH ruminal, por meio de bólus intraruminal de mensuração contínua. No decorrer do 1º dia foram coletadas amostras de fluido ruminal, sangue, fezes e urina e realizado exame clínico em oito momentos (zero, 3, 6, 9, 12, 15, 18 e 24h). Nove horas após o oferecimento matinal dos alimentos foram mensurados os movimentos ruminais (MR) no 2º e 3º dias. O pH ruminal na ARAGCC foi sempre inferior ao período basal, com duração da acidose de 547 &#177; 215 min, pH mínimo de 5,38 &#177; 0,16 e pH médio durante a acidose de 5,62 &#177; 0,1. Essa foi provocada principalmente por AGCC (máximo de 118,4 &#177; 9,3 mM/L), com máxima produção de ácido láctico (7,17mM/L) e de ácido láctico D (0,56 mM/L) na 6ª h. A osmolaridade foi máxima na 3ª h (405,5 &#177; 45,2 mOsm/L) influenciada pelo ácido láctico e teor de glicose ruminal. O CMS foi reduzido de 10 &#177; 1,23 kg no período basal em 66,3% no 1º d e 48% no 2º d regularizando-se no 3º. Quanto menor o pH médio da ARAGCC (R2 = 0,679), o TR (R2 = 0,807) a MR (R2 = 0,739) e quanto maior a osmolaridade ruminal (R2 = 0,5461) menor o CMS. O tempo para consumir 1 kg de MS aumentou de 32 &#177; 4 min no tempo basal para 94 no 1º d e 90 min no 2º d, normalizando-se no 3º. O TR foi reduzido de 450 &#177; 68 min no período basal em 58,4% no 1º d, em 48,7% no 2º d e em 20,9% no 3º d e foi influenciado positivamente pelo pH médio (R2 = 0,807). Os animais não modificaram o tempo de ócio em estação, mas aumentaram o tempo o de decúbito em relação ao período basal (380 &#177; 60 min) em 38,9% no 1º d em 26,6 % no 2º, regularizando-se no 3º. O decúbito foi mais prolongado quanto menor foi o pH ruminal mínimo (R2 = 0,466) e o grau de depressão neurológica (R2 = 0,616). Quanto menor o pH mínimo (R2 = 0,639) e maior o teor de lactato L ruminal (R2 = 0,373) maior o grau de depressão neurológica. O potencial de oxirredução, a acidez titulável e o tempo de redução de azul de metileno, em conjunto com o pH ruminal, podem auxiliar no diagnóstico da ARAGCC. / Thirteen, rumen cannulated, Nellore cows (544.2 &#177; 47 kg) were used in two different studies. The first one was carried out to set up a standard model for induction of rumen acidosis by short chain fatty acid (RASCFA) in heavier cattle (n= 3 cows) with the use of citrus pulp (CF) (1.65% BW of CF into the rumen). The remaining, studied the effect of RASCFA on ruminal metabolism, behavior changes, clinical and diagnostics aspects (n=10). The cows were housed in individual tie stalls and fed twice a day 75% coast-cross hay and 25% commercial concentrates, for 45d before the trials, with feed intake (FI) monitored. The standard model caused initially rumen lactic acidosis, but after some corrections (g CP = BW 0.75 x 54.7) induced RASCFA adequately (rumen pH between 5.8 and 5.2 for at least 5h). On the day before and for three consecutive days after induction the following variables were recorded every 5 min: time spending for rumination (TR), for feeding intake (TFI), for idle laying down (ILD) or idle standing (IS). On the day before and during the day of induction an intraruminal bolus for measuring rumen, pH each 5 min, were installed. Rumen fluid, blood, fecal and urine samples were collected and clinical examination carried out every three hour on the day of induction. Rumen movements (RM) were also recorded on the 2ndand 3rd d 9h after the morning feeding. The rumen pH of RASCFA was always lower than the basal time and the lasting of acidosis was 547 &#177; 215 min, minimum pH 5.38 &#177; 0.16 and the average pH during acidosis 5.62 &#177; 0.1. The rumen acidosis was caused mainly by SCFA (maximum 118.4 &#177; 9.3 mM/L), L-lactic acid (7.17mM/L) and D-lactic acid (0.56 mM/L) on the 6thh. Osmolality was maximum at the 3rdh (405.5 &#177; 45.2 mOsm/L) mostly caused by lactic acid and glucose. FI was reduced 66.3 % on the 1std and 48% on the 2ndd returning to normal status on the 3rd d (basal 10 &#177; 1,23 kg). The FI was positively influenced by the average rumen pH (R2 = 0.679), the RM (R2 = 0.807), and MR (R2 = 0.739), but negatively by the rumen osmolality (R2 = 0.546). The time for consumption of 1 kg DM was higher on the 1std (94 min) and 2nd d (90 min) but recovery on the 3rd d (basal 32 &#177; 4 min). The TR was reduced on the 1st d (58.4%), 2nd d (48.7%) and 3rd d (20.9) (basal 450 &#177; 68 min) and was mostly positively influenced by the average rumen pH (R2 = 0.8077). The IS hasnt change, but ILD time increased by 38.9% on the 1std, 26.6% on the 2ndd returning to normal on the 3rdd (basal 380 &#177; 60 min). The ILD time was negatively influenced by the minimum rumen pH (R2 = 0.466) and the neurological depression status (R2 = 0.616). The neurological depression status was positively influenced by the rumen minimum pH (R2 = 0.639) and positively by the level of rumen L-lactic acid (R2 = 0.3733). The tests of redox potential, titratable acidity and time for reduction of methylene blue, along with rumen pH, are good alternatives for diagnosing RASCFA.

Foram realizados dois ensaios experimentais a fim de avaliar o fornecimento de dieta úmida para frangos de corte e poedeiras comerciais. Os experimentos foram realizados nos galpões experimentais de frangos de corte e galpões de postura do setor de avicultura do Campus de Pirassununga da Universidade de São Paulo. Para frangos de corte, foram utilizados 960 animais distribuídos em delineamento inteiramente casualizado, com 6 tratamentos (nível de inclusão de água na dieta: 0%, 10%, 20%, 30%, 40% e 50%), com 4 repetições de 40 aves cada uma, sendo avaliados ganho de peso, conversão alimentar e consumo de ração. No dia do alojamento e aos 7 e 21 dias, duas aves por repetição foram abatidas para a avaliação histológica da morfologia intestinal. Para as poedeiras, foram utilizadas 192 aves, também distribuídas em delineamento inteiramente casualizado e divididas conforme o nível de inclusão de água na dieta, com 4 repetições de 8 aves por parcela experimental. Neste caso, foram determinados consumo de ração, conversão alimentar, produção de ovos, gravidade específica, espessura da casca e peso dos ovos. Semanalmente foi monitorada a temperatura corporal de duas aves por repetição de ambos os experimentos. A dieta úmida proporcionou uma melhor redução no consumo de ração e melhor conversão alimentar em ambos os experimentos. / Two experimental rehearsals were accomplished in order to evaluate the supply of wet feed for broilers chickens and commercial layers. The experiments were ccomplished at the experimental hangars of male chickens and posture the section of aviculture of the University of São Paulo - Campus of Pirassununga. Nine hundred sixty male chickens were used distributed, with 6 treatments (level of inclusion of water in the diet: 0%, 10%, 20%, 30%, 40% and 50%), were randomly assigned, with four repetitions of fourty birds each a, being appraised body weight gain, feed conversion and feed intake. In the day of the lodging and to the 7 and 21 days, two birds for repetition were abated for the evaluation of the intestinal morphology. For the layers, 192 birds were used, also distributed entirely in delineamento casualizado and divided according to the level of inclusion of water in the diet, were randomly assigned with four repetitions of eight birds each. In this case, they were certain feed intake, feed conversion, eggs production, specific gravity, thickness of the peel and eggs weight. The corporal temperature of two birds was weekly monitored by repetition of both experiments. The wet feed provided a better reduction in the feed intake and better alimentary conversion in both experiments.

A menor capacidade de consumo voluntário de alimentos das fêmeas atuais pode ser evidenciada na fase de lactação. As fêmeas são mais exigentes nutricionalmente, pois o consumo de ração durante o período de lactação pode se tornar insuficiente para atender às exigências de mantença e máxima produção de leite das porcas. Com isso, o consumo voluntário de ração deve ser estimulado para evitar mínima mobilização de reservas corporais das fêmeas, garantindo assim, maior produção de leite e menor perda de peso das fêmeas até o desmame. O uso de substâncias flavorizantes, edulcorantes e do butirato de sódio estão sendo estudados com o objetivo de estimular o consumo voluntário. O experimento foi conduzido com o objetivo de determinar o consumo voluntário e a performance de 14 fêmeas suínas de primeiro parto em lactação, alimentadas com ração de lactação sem o uso de aditivo (T1) e ração de lactação contendo butirato de sódio (T2), edulcorante (T3) e flavorizante (T4), além do desempenho da leitegada de cada fêmea. As dietas experimentais foram administradas a partir do dia seguinte ao parto, até o dia do desmame. Os parâmetros avaliados nas porcas foram: consumo alimentar voluntário, perda de peso durante a lactação, variação na espessura de toucinho, produção de leite e intervalo desmama-estro subseqüente. O ganho de peso dos leitões foi também analisado. Foi observado maior consumo (P<0,05), pelas fêmeas do tratamento controle (T1) quando comparado com os demais tratamentos (T2, T3, T4). Já em relação à produção de leite, não foi evidenciado efeito significativo para nenhum dos tratamentos (P>0,05), porém observa-se uma diferença numérica entre os tratamentos, favorável ao T2. Quando observado peso e espessura de toucinho na entrada da maternidade e no desmame e o intervalo desmama estro, também não foram observadas diferenças significativas (P<0,05). Quanto ao peso dos leitões não foram evidenciadas diferenças significativas. Assim, a adição de substâncias flavorizantes, edulcorante e butirato de sódio em fêmeas primíparas, nas concentrações utilizadas nesse estudo, não apresentou efeito para nenhuma das variáveis, exceto para o consumo voluntário das fêmeas, de modo que são necessários novos estudos para averiguar a interferência desta suplementação sobre o consumo voluntário de alimentos, levando em consideração as linhagens híbridas existentes no mercado. / Sows of modern genotypes have a lower feed intake, whereas nutritional requirements have increased, especially due to higher number of piglets born per sow and thus to higher milk yield. Especially during lactation, if nutritional demands of sows are not met, a high milk production can lead to a negative energy balance, and thus to both a decrease in body fat reserves and a lower body weight at weaning. An alternative to avoid excessive body reserves depletion is feed supplementation with substances which can increase voluntary feed intake, among them flavors, sweeteners and butyric acid. The aim of this study was to assess the effects of such substances towards voluntary feed intake, milk production and performance of sows, and on litters weight gain, after supplementation of sows feeding during lactation. Fourteen first-parturition sows were allocated in one of the following treatments: feeding without any supplement (T1); supplementation with either butyric acid (T2), sweeteners (T3) or flavors (T4). Experimental diets were given from the day after parturition until the weaning. The following parameters were evaluated in sows: feed intake, loss of weight during lactation, variation of backfat thickness, milk production and weaning-estrus interval. Weight gain of piglets was also recorded. Feed intake of sows allocated at T1 group was higher (P<0.05), in comparison with T2, T3 and T4 groups. There was a trend towards a higher milk production of T2 group, although results were not statistically significant (P>0.05). In conclusion, supplementation of primiparous sows diet with flavours, sweeteners and butyric acid, at least at levels utilized in this study, did not produced any changes on the evaluated parameters, except for the voluntary feed intake of sows. Thus, futher investigations on the effects of those additives on voluntary feed intake and satiety mechanisms of new lineages pigs must be conducted.