RESUMO
This study aimed to evaluate the effect of autoclave processing on compressive stress of spongy and cortical bones, and the effect of autoclaved bones as chewing agents to reduce dental calculus in adult dogs. Spongy and cortical bones were autoclaved (1 ATM, 30 min, and 120°C) and compressive strength was evaluated in autoclaved and raw bone specimens. Autoclaved bones were offered to ten Beagle dogs divided into two groups of 5 dogs each: Group 1 - received a portion of the autoclaved bovine cortical bone (ACB) and Group 2 - received a portion of the autoclaved bovine spongy bone (ASB). Prior to the experimental period (1-d) and every two days thereafter, oral photographs were taken on both sides of the dental arch to evaluate dental calculus reduction over time. The vestibular surface of the canines, premolars, and molars teeth was evaluated using integration software to measure the proportion between the area covered by calculus and the total teeth area. The effect of bone type, treatment (raw vs. autoclaved), and their interaction were evaluated using the PROC GLIMMIX procedure of SAS (version 9.4). Linear equations were generated to estimate calculus reduction over time for ACB and ASB. Compressive strength was higher (P < 0.05) in cortical bones compared to spongy bones. However, the autoclaving procedure did not affect (P > 0.05) compressive strength, regardless of the bone type. The teeth area covered by calculus of dogs that were offered ACB reduced from 41% to 32% in 5 days, and at the end of 15 days a reduction of 62.2% was observed, resulting in a remaining of 15.5% of teeth area covered by calculus. In this group, the dental calculus area reduced by 57.7% after 5 days, and at the end of the trial, only 5.4% of teeth were still covered by calculus, which represents a reduction of 81%. The linear regression analysis revealed no significant difference between the slopes for the ACB and ASB equations (P > 0.05). No health complications such as tooth fracture, intestinal obstructions, and oral lesions were observed throughout the study. Our results demonstrated that the autoclave processing did not impair compressive strength of spongy and cortical bones. This corroborates with the results observed in vivo, which suggests that autoclaved bones are chewing agents for adult dogs with additional benefits of lower risk of bacterial contamination.
RESUMO
The effectiveness of rice protein coatings enriched with essential oils on maintaining interior quality of fresh eggs was evaluated during storage at 20°C for 6 wk. Egg quality was assessed by weight loss, Haugh unit (HU), albumen pH, and yolk index (YI) in uncoated eggs (control treatment) and eggs coated with rice protein concentrate at 8% enriched or not with different essential oils (1%): tea tree (Melaleuca alternifolia), copaíba (Copaifera langsdorffii), or thymo (Thymus vulgaris). The HU and YI were higher in coated eggs (P < 0.001). Data were submitted to variance analysis, and the statistical models included the effects of treatments (coating types), storage periods (weeks), and interaction (treatments by storage periods). Weight loss increased (P < 0.001) during long-term storage. Uncoated eggs showed the highest weight loss (5.43%), whereas coatings of rice protein alone (4.23%) or enriched with tea tree (4.10%), copaíba (3.90%), and thymo (4.08%) solutions were effective in preventing weight lost (P < 0.001). The coating use preserved the internal quality of the eggs for up to 3 wk longer than uncoated eggs in terms of HU, YI, and pH. Uncoated eggs had the worst (P < 0.001) HU (58.46), albumen pH (9.48), and YI (0.33) after 6 wk of storage. In conclusion, the use of coatings based on rice protein concentrate enriched with different essential oils influences the internal quality of eggs during storage and may be an effective alternative for increasing the shelf life of commercial eggs.
Assuntos
Ovos/análise , Armazenamento de Alimentos/métodos , Óleos Voláteis/administração & dosagem , Oryza/química , Proteínas de Vegetais Comestíveis/administração & dosagem , Animais , GalinhasRESUMO
The effectiveness of rice protein coatings or mineral oil on maintaining interior quality and eggshell breaking strength of fresh eggs was evaluated during storage at 20°C for 8 wk. Egg quality was assessed by weight loss, Haugh unit (HU), albumen pH, yolk index (YI), shell strength, and scanning electron microscopy in uncoated eggs (control treatment) and eggs coated with mineral oil or rice protein concentrate at 5, 10, or 15%. The HU and YI were higher in coated eggs (P < 0.001). Weight loss increased (P < 0.001) during long-term storage. Uncoated eggs showed the highest weight loss (8.28%), whereas mineral oil (0.87%) and rice protein at 5% (5.60%), 10% (5.45%), 15% (5.54%) solutions were effective in preventing weight lost (P < 0.001). The use of the coatings preserved the internal quality of the eggs for up to 4 wk longer than uncoated eggs (HU, YI, and pH). Uncoated eggs had the worst (P < 0.001) HU (54.45), albumen pH (9.18), and YI (0.28) after 8 wk of storage. Among the coated eggs, the mineral oil had the best values of HU (70.54), pH (8.48), and YI (0.35) after storage. The eggs coated with 5, 10, and 15% of rice protein presented results with similar intern quality between them and intermediary quality in relation to the others treatments during all the storage period. Scanning electron microscopy demonstrated a lower surface porosity in coated eggshell, indicating that the use of the coating may provide a protective barrier against the transfer of gases and moisture. In conclusion, the use of coatings based on rice protein concentrate or mineral oil influences the internal quality of eggs during storage and may be an effective alternative for increasing the shelf-life of commercial eggs.
Assuntos
Casca de Ovo/química , Ovos/análise , Armazenamento de Alimentos/métodos , Oryza/química , Proteínas de Plantas/química , Animais , Galinhas , Conservação de Alimentos/métodosRESUMO
Glycerol is a humectant, which reduces water activity when added to the diet. This property seems to offer dietary benefits, specifically in high-moisture diets for cats, where some humectants cannot be used. According to the U.S. Food and Drug Administration, glycerol is generally recognized as sustenance safe (GRAS). It is suggested that cats are able to metabolize glycerol and use it as an energy source without compromising health. Three experiments were conducted to evaluate the following characteristics of glycerol in the diet for cats: 1) a preference test, 2) digestibility, ME, and fecal and urinary characteristics, and 3) postprandial plasma glycemia. Twelve healthy adult female cats were randomly distributed among 4 treatments consisting of a basal diet (4,090 kcal ME/kg DM, 32% CP, 11% fat, 2.3% crude fiber, and 7.0% ash) and 3 diets with varying percentages of glycerol, made by replacing the basal diet with 2.5, 5.0, and 10.0% purified glycerol (99.5%). The inclusion of glycerol proportionally reduced ( < 0.05) water activity in the diets. The preference test was conducted by observing the contrast between the basal diet and the 5.0% and 10% glycerol diets. Cats did not show a preference for any diet in particular ( > 0.05). The digestibility assays showed that increasing dietary glycerol levels did not affect food intake or the apparent total tract digestibility of macronutrients and energy ( > 0.05). The inclusion of glycerol in the diets did not alter the stool moisture, fecal score, or urine volume. However, glycerol was detected in urine when it was incorporated into the diet at 10%. Glycemia increased up to 900 min following the first meal after the fasting period with no difference between treatments, even when the means were adjusted for food intake. The blood glucose area under the curve also showed no significant difference between treatments ( > 0.05). Cats accepted glycerol under the conditions of the study, and its nutritional value was determined as it has been done for other species. The ME of glycerol for adult cats was estimated to be 3,185 kcal/kg DM. Supplementing the diets of the cats with 10% glycerol may exceed their capacity to metabolize glycerol, possibly leading to urinary excretions.
Assuntos
Ração Animal/análise , Gatos/fisiologia , Dieta/veterinária , Digestão/fisiologia , Metabolismo Energético/fisiologia , Glicerol/metabolismo , Fenômenos Fisiológicos da Nutrição Animal , Animais , Glicemia , Suplementos Nutricionais , Ingestão de Alimentos , Fezes , Comportamento Alimentar , Feminino , Glicerol/química , Valor Nutritivo , Período Pós-PrandialRESUMO
Semen from the first 15mL of the ejaculate (P1) obtained from two boars (30mL) was diluted in glycine-egg yolk extender, cooled at 5°C in a special container and rediluted in standard doses of 3x109 mobile spermatozoa after 12h of storage. Semen was also stored up to 24h after redilution. The physical characteristics of the semen were evaluated at different storage periods (fresh, 0h, 12h, rediluted, 24h, and 36h). The reproductive performance of the boars and their fertility regarding the insemination of primiparous sows were also determined. Two treatments were used: T1-15B sows inseminated with semen originated from hyperconcentrated heterospermic doses (15x109 mobile spermatozoa per dose), rediluted after 12h of storage at 5°C for standard doses of 3x109 mobile spermatozoa per dose and stored at 5°C up to 24h after redilution (n=10); T2-3B sows inseminated with standard heterospermic doses (3x109 mobile spermatozoa per dose), stored at 5°C up to 36h after semen collection (n=10). There was no effect (P>0.05) of treatments on the spermatic motility, even though a pronounced decrease (P>0.05) of their values at 12h of storage was recorded. However, they remained higher than 70% until 36h. There was effect of treatments on spermatic vigour at 0h (P<0.05), when T1-15B vigour was higher. There was also effect of the storage period for both treatments with a progressive decrease throughout 36h of storage, although the differences were not always significant. Pregnancy rates (90%) and the number of total farrowed piglets (15, 11-T1-15B; 13, 44- T2-3B) did not differ (P>0.05) between the treatments. It was concluded that the semen hyperconcentration of 15 billion of mobile spermatozoa per dose, stored at 5°C for 12h, did not result in drawbacks considering the physical characteristics of the semen, maintaining the pregnancy rates and prolificacy of the inseminated sows.
Os primeiros 15mL do ejaculado (P1) de dois varrões foram coletados (30mL) e diluídos em diluidor glicina-gema de ovo, resfriados a 5°C em contêiner especial e rediluídos para doses padrão de 3x109 espermatozoides (sptz) móveis, após 12 horas de armazenamento. Além disso, foram armazenados por até 24 horas após a rediluição, sendo as características físicas avaliadas em diferentes períodos de estocagem (fresco, zero hora, 12h, Red12h, 24h e 36h) e a fertilidade avaliada por meio de fêmeas primíparas inseminadas. Foram realizados dois tratamentos: T1-15B: porcas inseminadas com sêmen de doses heterospérmicas hiperconcentradas (15x109 sptz móveis/dose), rediluídas após 12 horas de armazenamento a 5°C para doses padrão de 3x109 sptz móveis/dose, e armazenadas a 5°C por até 24 horas após a rediluição (n=10); T2-3B: porcas inseminadas com doses heterospérmicas padrão (3x109 sptz móveis/dose), armazenadas a 5°C por até 36 horas após coleta. Não houve efeito (P>0.05) dos tratamentos sobre a motilidade espermática e, embora tenha ocorrido queda (P<0.05) às 12 horas, a motilidade foi superior a 70% durante as 36 horas de armazenamento. Houve efeito (P<0.05) dos tratamentos no tempo zero hora quanto ao vigor espermático, sendo E1T1-15B superior. Além disso, houve efeito do período de estocagem para os dois tratamentos, com queda progressiva do vigor ao longo das 36 horas, embora nem sempre as diferenças tenham sido significativas. As taxas de gestação (90%) e o número total de leitões nascidos (15, 11 - T1-15B; 13, 44 - T2-3B) não diferiram (P>0.05) entre os tratamentos. Concluiu-se que a hiperconcentração do sêmen para 15x109 sptz móveis/dose, armazenado a 5°C por 12 horas não resultou em prejuízos quanto à manutenção das características físicas do sêmen e ao desempenho reprodutivo dos varrões, sendo capaz de manter a taxa de gestação e a prolificidade das fêmeas inseminadas.
Assuntos
Animais , Análise do Sêmen/veterinária , Bancos de Esperma/métodos , Preservação do Sêmen/métodos , Preservação do Sêmen/veterinária , Suínos , Reprodução , Capacitação Espermática , Transporte EspermáticoRESUMO
OBJECTIVE: Evaluate the effect of raw bovine cortical bone (CB) (medullary bone cross-sectioned) and marrow or epiphyseal 'spongy' bone (SB) as chew items to reduce dental calculus in adult dogs. METHODS: Eight 3-year-old Beagle dogs were observed in two study periods. In the first study, the dogs each received a piece of bovine femur CB (122 ± 17 g) daily and in the second study, a piece of bovine femur SB (235 ± 27 g). The first study lasted 12 days and the second 20 days. Dental calculus was evaluated using image integration software. RESULTS: At the start of the studies, dental calculus covered 42.0% and 38.6% of the dental arcade areas, respectively. In study one, the chewing reduced the established dental calculus area to 27.1% (35.5% reduction) after 3 days and after 12 days the dental calculus covering was reduced to 12.3% (70.6% reduction). In study two, the dental calculus covered 16.8% (56.5% reduction) after 3 days, 7.1% (81.6% reduction) after 12 days and 4.7% (87.8% reduction) after 20 days. The CB remained largely intact after 24 h, but SB was reduced to smaller pieces and in some cases totally consumed after 24 h. No complications such as tooth fractures, pieces of bone stuck between teeth or intestinal obstructions were observed during the studies. CONCLUSIONS: Chewing raw bovine bones was an effective method of removing dental calculus in dogs. The SB bones removed dental calculus more efficiently in the short term.
Assuntos
Ração Animal , Cálculos Dentários/veterinária , Cães , Alimentos Crus , Animais , Osso e Ossos , Cálculos Dentários/prevenção & controle , MastigaçãoRESUMO
Two experiments were conducted to evaluate the effect of full-fat rice bran (FFRB) inclusion in dry diets with and without enzyme blend (EB) supplementation for adult dogs. The diets contained 0, 20, or 40% of FFRB, replacing the equivalent amount of wheat flour (WF). Experiment 1 evaluated the consumption and preference of diets using a simple choice method with 3 comparisons (0 vs. 20, 0 vs. 40, and 20 vs. 40% FFRB). Experiment 2 investigated the effect of EB supplementation on the apparent digestibility coefficients (ADC) of nutrients and GE, fecal characteristics, urinary pH, Ca and P balance, and ME of the diets. In Exp. 1, the results indicated that FFRB included in diets up to 40% did not affect the preference or consumption of food by dogs (P < 0.05). In Exp. 2, increasing levels of FFRB in the diet linearly reduced the ADC of nutrients, GE, and ME (P < 0.05). The addition of EB had no effect on any of the variables examined. Regression analysis enabled estimation of the ADC in FFRB; and ADC of DM, CP, ether extract, GE; and the apparent coefficient of ME were 60.5, 74.8, 88.4, 70.8, and 66.4%, respectively. The inclusion of 20 or 40% FFRB in the diets did not affect urinary pH but caused an imbalance in the Ca and P metabolism when included at 40% (P < 0.05), which could be one of the limitations for greater inclusion of FFRB. The ME of FFRB was estimated to be 3,443 kcal/kg DM. The FFRB appears to be palatable for adult dogs, and although ADC was reduced by 40% FFRB in the diet, this ingredient has the potential for inclusion at 20% of diets for dogs, depending on the other ingredients used to achieve adequate Ca and P balance. The inclusion greater than 20% tends to increase P in the diet and reverse the relationship between Ca and P.
Assuntos
Fenômenos Fisiológicos da Nutrição Animal , Dieta/veterinária , Digestão/efeitos dos fármacos , Cães/fisiologia , Oryza/química , Óleos de Plantas/farmacologia , Animais , Suplementos Nutricionais , Digestão/fisiologia , Fezes/química , Concentração de Íons de Hidrogênio , Óleos de Plantas/análise , Análise de Regressão , Óleo de Farelo de Arroz , Urina/químicaRESUMO
The objective of the present study was to investigate the effects of dietary-induced insulin enhancement during the late luteal phase on subsequent fertility of gilts. Fifty-two littermate cyclic gilts were subjected to dietary treatments where two energy sources were tested: corn starch (T1) and soybean oil (T2). The experimental diets were supposed to provide similar amounts of dietary energy, but from different sources. Gilts were fed ad libitum, starting day 8 of the estrous cycle, until the next standing heat. Blood sampling was performed in a subgroup of 20 gilts on days 14 and 21 of the cycle for analyses of glucose and insulin, and after ovulation detection until 18 h after ovulation for progesterone. All gilts were slaughtered on day 28 of pregnancy and the reproductive tracts recovered for further analysis. T1 gilts showed higher postprandial insulin peak on days 14 and 21 and lower glucose levels 4 h after feeding on day 14 (P<0.05), however, there were no treatment effects on plasma progesterone concentrations. Dietary energy sources did not affect average daily feed intake, body weight and backfat on day 28 of pregnancy. Estrous cycle length, estrus duration and time of ovulation were not affected by previous nutritional treatments either. T1 gilts showed higher ovulation rates, number of embryos, embryo weight and placental weight (P<0.05). There were no treatment effects on pregnancy rate, embryo survival rate and volume of amniotic fluid. A positive correlation between progesterone concentration 18 h after ovulation and ovulation rate was observed (r=0.75; P<0.01). These results suggest that it is possible to manipulate dietary insulin response in cyclic gilts and, thus, improve reproductive efficiency when feeding starch as the main energy source during the late luteal and follicular phases of the cycle.
Assuntos
Metabolismo Energético/fisiologia , Fertilidade/fisiologia , Insulina/farmacologia , Fase Luteal/fisiologia , Gravidez/fisiologia , Sus scrofa/fisiologia , Adiposidade/efeitos dos fármacos , Animais , Glicemia/análise , Peso Corporal/efeitos dos fármacos , Suplementos Nutricionais , Ingestão de Alimentos/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Feminino , Fertilidade/efeitos dos fármacos , Insulina/administração & dosagem , Insulina/sangue , Modelos Lineares , Gravidez/efeitos dos fármacos , Progesterona/sangue , Óleo de Soja , AmidoRESUMO
Duas porções do ejaculado suíno - primeiros 15mL da fração espermática rica (P1) e o restante do ejaculado (P2) - foram coletadas semanalmente de cinco varrões e submetidas a dois protocolos de resfriamento, diluição no diluidor MR-A® e conservação a 17°C (T1) ou no diluidor glicina-gema de ovo e conservação a 5°C (T2). As doses foram avaliadas no que se refere à motilidade, ao vigor e à morfologia espermáticas no sêmen a fresco e em diferentes tempos de estocagem. Todos os tratamentos mantiveram uma motilidade aceitável, superior a 50 por cento, nas primeiras 24 horas de armazenamento. O grupo P2T2 manteve uma motilidade similar (P>0,05) ao longo de todo o período de resfriamento (72 horas), sendo inclusive superior aos demais neste período, enquanto os outros tratamentos apresentaram uma redução da motilidade no decorrer do tempo de armazenamento. Com relação às características morfológicas do sêmen, não se observaram diferenças (P>0,05) quanto às porcentagens de espermatozoides normais entre as duas frações do ejaculado fresco. Ainda, todos os tratamentos mantiveram-se dentro dos limites aceitáveis, independentemente do tempo de armazenamento. A P1 parece ser mais adequada à produção de doses para o transporte em virtude de seu pequeno volume e alta concentração, enquanto o restante do ejaculado (P2) pode ser utilizado com eficiência dentro da própria granja.
Two portions of boar ejaculate - first 15mL of the sperm rich fraction (P1) and the rest of the ejaculate (P2) - were collected weekly from 5 mature boars and submitted to two cooling methods, extended in MR-A® and cooled at 17°C (T1) or extended in glycine-egg yolk and cooled at 5°C (T2). Spermatozoa motility, vigor, and morphological characteristics were evaluated immediately after collection and in different storage times. All treatments kept an acceptable motility, higher than 50 percent, in the first 24h of storage. The P2T2 maintained a similar motility (P>0.05) throughout the cooling storage (72h) and was superior in that period, while the other treatments presented a decrease in motility related to time. There was no difference between the two portions regarding the total number of normal spermatozoa in the fresh semen (P>0.05). All treatments showed morphological abnormalities within the acceptable thresholds, irrespectively of the storage time. Thus, due to low volume and high concentration, P1 seems to be more adequate for sperm dose transportation. Furthermore, this methodology will allow the development of new proposals concerning the transportation of swine semen, while the rest of the ejaculate could be used in farm routines to produce conventional liquid semen doses.
RESUMO
The effect of an oral treatment with the tartrate salt of tylvalosin on the development of proliferative enteropathy in 60 experimentally challenged pigs was studied. Thirty of the pigs were fed a diet medicated with 50 ppm tylvalosin and 30 were fed the unmedicated diet. The treated animals started to receive the medicated feed the day before they were inoculated, and continued to receive it for 14 days. The pigs' bodyweight, feed consumption and clinical signs were evaluated, and they were examined postmortem 20 days after inoculation, and samples of ileum were collected for immunohistochemistry (IHC) for Lawsonia intracellularis. Clinical signs of the disease were more evident in the untreated group than in the treated group. The average daily weight gain, average daily feed consumption and feed conversion efficiency were better in the treated group. The combined length of intestine with lesions was 2847 cm in the untreated group and 183 cm in the treated group. The tylvalosin treatment significantly reduced the level of L intracellularis infection; almost half of the treated pigs were IHC-negative compared with 3.3 per cent of the untreated pigs.
Assuntos
Antibacterianos/administração & dosagem , Antibacterianos/uso terapêutico , Infecções por Desulfovibrionaceae/veterinária , Ileíte/veterinária , Doenças dos Suínos/prevenção & controle , Tilosina/análogos & derivados , Ração Animal , Animais , Infecções por Desulfovibrionaceae/prevenção & controle , Ileíte/prevenção & controle , Suínos , Doenças dos Suínos/microbiologia , Fatores de Tempo , Tilosina/administração & dosagem , Tilosina/uso terapêuticoRESUMO
Cinqüenta e quatro marrãs cíclicas, uniformizadas quanto à linhagem, família, ganho de peso, espessura de toucinho, peso, precocidade sexual, número de cios e escore clínico, foram alocadas em dois grupos experimentais com dietas isocalóricas, isoprotéicas e isolisínicas. Duas fontes de energia foram testadas: amido de milho (T1) e óleo de soja (T2). Sincronizou-se o segundo estro com allyl-trenbolone, para inseminação no terceiro estro. Foi realizada cateterização não cirúrgica em 21 marrãs, submetidas a dois ciclos de coleta para dosagem de glicose e insulina, aos 14 e 21 dias do ciclo. Todas as marrãs foram abatidas aos 28,6 dias de gestação média, para análises biométricas do trato reprodutivo. Marrãs do T1 apresentaram maior taxa ovulatória em relação às do T2 (16,52 vs 14,70, P<0,01). Não houve diferença entre os tratamentos nas taxas de prenhez e sobrevivência embrionária. É possível alterar a eficiência reprodutiva por intermédio de manipulação dietética, mesmo em marrãs em estado anabólico. O uso do amido de milho na fase pré-cobertua melhorou a eficiência reprodutiva dos animais avaliados.
Fifty four cyclic gilts were randomly selected and uniformized according to genetic background, litter of origin, weight gain, backfat, number of cycles and clinical score. Gilts were alloted to one of two groups fed isocaloric, isoproteic and isolysinic diets. Two energy sources were tested: corn starch (T1) and soybean oil (T2). Second estrus was synchronized with oral allyl-trenbolone, so that insemination was carried out at third estrus. Indweeling catheters were implanted by non-surgical technic in 21 gilts, which were submitted to consecutive blood samplings for glicose and insulin determination. Timing of ovulation was estimated by means of ultrasonography. All gilts were slaughtered at an average gestation lenght of 28.6 days. Starch-fed gilts (T1) showed higher ovulation rates than T2 gilts (16.52 vs 14.70; P<0.01). There was no effect of treatments on pregnancy rate and embryo survival. Results indicate it is possible to manipulate reproductive efficiency through diet even in anabolic experimental models like cyclic gilts. Feeding starch as main energy source during pre-mating flushing phase improved reproductive efficiency of cyclic gilts.
Assuntos
Animais , Feminino , Fertilização/fisiologia , Ovulação , Prenhez , Ração Animal/análise , Óleo de Soja , Amidos e Féculas , Suínos , Sincronização do Estro/métodosRESUMO
Foram utilizadas 22 novilhas, 11 da raça Holandesas e 11 da Guzerá, com peso vivo (PV) inicial de 189kg. Após o abate inicial de seis animais de cada raça, outros dois grupos, cinco animais de cada raça, passaram a receber dieta à base de feno de Tifton 85 (Cynodon spp.), milho, farelo de soja e mistura mineral, para ganho diário de 1kg de peso vivo (PV). O abate final ocorreu após ganho de peso de 100kg. Durante os dois abates, todos os tecidos foram pesados e amostrados, retirando-se como amostra representativa da carcaça entre a nona e a décima primeira costela para determinação dos conteúdos corporais de Ca, P, Mg, Na e K. Determinaram-se a composição corporal e as exigências nutricionais desses minerais para ganho de 1kg de PV. Houve decréscimo na concentração dos cinco macrominerais no peso de corpo vazio e no peso ganho com a elevação do PV. Não houve diferença entre as raças quanto às exigências nutricionais dos macrominerais. As exigências dietéticas totais de Ca, P, Mg, Na e K para animais de 200kg de PV foram de 11,57; 5,97; 0,36; 1,30 e 0,86g/dia, respectivamente.
Twenty-two heifers, 11 Holstein and 11 Guzera, with initial live weight (LW) of 189kg were used in this study. Six animals of each breed were slaughtered (treatment R), and two groups of five animals of each breed were fed ad libitum diet of Tifton 85 (Cynodon spp.) hay, ground corn, soybean meal and mixture minerals, for a daily gain of 1kg. The animals were slaughtered after reaching weight gain of 100kg. All tissues were weighted and representative samples were taken from the ninth to eleventh rib, and analyzed for body contents of Ca, P, Mg, Na and K. The body composition and the mineral requirements for a 1kg LW daily weight gain were determined. Decreases in the concentration of macrominerals in the empty body weight and in carcass weight gain were related to LW increased. No differences among breeds for macrominerals were observed. The Ca, P, Mg, Na and K dietary requirements for animals of 200kg of LW were 11.57; 5.97; 0.36; 1.30 and 0.86g/day, respectively.