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This study compared early weaning (EW; 150 days) with conventional weaning (CW; 240 days) in Nellore young bulls, evaluating performance, carcass characteristics, and meat quality. A total of 74 non-castrated male calves were divided into two weaning strategies: EW (n = 37) and CW (n = 37). During the growth phase, which lasted 454 ± 14 d for EW calves and 359 ± 16 d for CW calves, animals received a protein-energy supplement at a ratio of 5 g per kg of body weight while grazing Brachiaria brizantha cv. Marandu. The animals were managed for an 87d finishing phase in three collective feedlot pens, with a 3-week adaptation protocol, starting with corn silage to a concentrate ratio of 55:45 and reaching a ratio of 30:70 in the final diet. Body weight, average daily gain (ADG), dry matter intake (DMI), feed efficiency (FE), carcass characteristics, and meat quality were evaluated. The EW group was approximately 44 kg lighter than the CW at the time of conventional weaning (p < 0.001). However, this weight difference did not influence ADG, DMI, and FE in the finishing phase. No significant differences were observed in carcass characteristics such as yield percentage, loin area, subcutaneous fat thickness, and meat quality, except for the weight of primal cuts, which was greater in the CW group (p < 0.001). Thus, although calves weaned early are lighter throughout subsequent production phases than those weaned conventionally, performance, efficiency, carcass yield, and meat quality are not affected.

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We aimed to evaluate the effects of early weaning on the productive and reproductive characteristics of Nelore heifer progeny. Ninety-five calves from primiparous (PRI) and multiparous (MUL) dams were assigned to one of two weaning strategies; 1) early weaning at 150 d (149 ±â€…1.97) of age (EW; n = 16 from PRI and 31 from MUL); or 2) conventional weaning at 240 d (247 ±â€…2.41) of age (CW; 16 from PRI and 32 from MUL). All heifers received ~5 g/kg of body weight (BW) of creep-feed as fed from 90 d of age until weaning. After weaning, each group of heifers was transferred to a Brachiaria spp. paddock and received 5 g/kg of BW of a protein-energy supplement until 12 mo of age. Then, heifers were confined and fed a diet with a ratio of 79:31 (corn silage: concentrate) for 4 mo, during which they were submitted to a hormonal protocol to induce puberty and timed artificial insemination (TAI). Reproductive tract score (RTS, 1 to 5 scale: 1 being infantile and 5 being cyclic) and endometrial thickness were determined at 12 mo of age, rump fat thickness (RFT), and BW every 28 ±â€…4 d through the breeding season, and plasma concentrations of IGF-I were evaluated at 12, 14, and 16 mo. At 15.6 mo of age heifers were submitted to a P4/E2 protocol for TAI at day 0 (D0), and a second TAI was performed at D22 in nonpregnant heifers. Ultrasound was used to determine the presence of corpus luteum on D10 and dominant follicle (DF) diameter and blood perfusion on D2 and D0. Data were analyzed using SAS by ANOVA or logistic regression. Though heifers from EW were lighter (P < 0.05) than CW at postweaning time points and CW presented a greater (P = 0.002) RFT than EW heifers from 11 to 15 mo, weaning strategy did not affect (P > 0.1) body condition score at TAI. Concentrations of IGF-I did not differ (P > 0.1) between heifers weaned at 150 and 240 d. The proportion of pubertal heifers, endometrium tone and thickness, and RTS at 16 mo did not differ (P > 0.1) between EW and CW groups. The diameter of DF on D2 and D0 and follicular blood perfusion on D0 were greater (P < 0.05) for heifers in the CW group than EW group, but P/AI at first and second TAI did not differ (P > 0.1) between groups. In conclusion, early weaning in Nelore heifers moderately reduces postweaning growth but does not affect puberty and reproductive performance before the breeding season when submitted to confinement.

In beef cattle operations, heifers represent the most current genetic improvement and are integral to the future of the herd. Factors such as age and weight at weaning and average daily gains impact fertility and longevity of beef heifers. The present study compared the effects of two weaning strategies (150 d of age vs. 240 d of age) on the growth and reproductive characteristics of Nelore Heifers. Comparing the weaning strategies of Nelore heifers, the present study indicates that: 1) heifers weaned at 150 d were lighter than heifers weaned at 240 d; and 2) puberty, concentration of IGF-I, and reproductive tract development and performance did not differ between weaning strategies. Shows that early weaning in Nelore heifers moderately reduces postweaning growth but does not affect reproductive performance.

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This study aimed to evaluate the effects of early weaning (EW) on body composition, hormone concentrations and metabolites, and reproductive performance of Nelore cows in the subsequent breeding season (BS). Suckled cows that became pregnant by timed-AI (TAI) in the 2020-BS were exposed in 2021 to early weaning at 150 d (27 primiparous [PRI] and 74 multiparous [MUL]) or conventional weaning (CW) at 240 d postpartum (30 PRI and 77 MUL). Body weight (BW) and body condition score (BCS) were determined at 2020-BS, EW, CW, prepartum, and 2021-BS. Blood samples were collected at EW, CW, prepartum (54.75 ±â€…0.56 d prepartum), and 2021-TAI and assayed for insulin-like growth factor-1 (IGF-I), non-esterified fatty acid (NEFA), and ß-hydroxybutyrate (BHB) concentrations. In 2021-BS, cows were exposed to a P4/E2-based protocol for TAI at day 0 (D0), and a second TAI was performed at D22 in females detected with luteolysis (D20) by Doppler ultrasound. The presence of corpus luteum (CL) on D10, estrous expression, and dominant follicle (DF) diameter, and blood perfusion (BP) on D2 and D0 were determined. Data were analyzed by ANOVA or logistic regression of SAS as a 2 × 2 factorial with main factors of parity (PRI or MUL) and weaning strategy (EW or CW). An interaction of parity and weaning strategy was not observed (P > 0.1), but the weight (kg) and BCS were greater (P < 0.05) in MUL cows at the five timepoints, and EW cows were heavier than CW at the moment of CW (541 vs. 493 kg; and 5.3 vs. 4.3), prepartum (551 vs. 506 kg; and 5.2 vs. 4.4) and 2021-BS (475 vs. 450 kg; and 4.5 vs. 3.7). Plasma urea concentration at 2021-BS was greater (P = 0.01) for PRI than for MUL. A parity-by-time interaction was observed (P ≤ 0.05) for concentrations of IGF-I, NEFA, and BHB. PRI cows had greater (P ≤ 0.05) concentrations of IGF-I at EW and greater (P ≤ 0.05) prepartum concentrations of NEFA and BHB than MUL cows. The proportion of cows with CL at D10 was not affected (P > 0.1) by weaning but was greater (P < 0.05) in MUL than in PRI cows (40.4 vs. 15.7%). The diameter of DF and proportion of BP on D0 were greater (P < 0.05) in EW cows than in CW cows. The pregnancy rate (P/AI, %) at the first TAI was greater (P < 0.05) in EW cows (60% vs. 45%), whereas no difference (P > 0.1) was observed at the second TAI. Cumulative P/AI (first and second TAIs) was greater (P < 0.05) in EW cows (81% vs. 63%). In conclusion, weaning at 150 d in Nelore cattle is a strategy to successfully recover the parous cow's body condition and to improve pregnancy success in the next BS, regardless of the cow's parity order.

The nutritional condition and body energy reserves at parturition are important factors that can affect the reproductive performance of suckled Nelore cows. Also, decreasing the weaning time can benefit the cow's metabolic status. The present study evaluated the effect of two periods of weaning (150 vs. 240 d) on the reproductive performance of the Nelore dam in the subsequent breeding season. The results of the present study indicate that early weaning: 1) improves the body condition, rump fat thickness, and metabolic condition of Nelore cows for the subsequent breeding season; 2) provides better ovarian follicle growth and blood perfusion during the subsequent timed artificial insemination program; 3) enhances the pregnancy rates in the subsequent breeding season.

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This study aimed to evaluate the effectiveness of different additives in preventing urolithiasis in lambs fed a diet rich in concentrate and their impact on performance and blood and urinary parameters. Thirty-two noncastrated male lambs, crossbred Dorper × Santa Inês, with initial body weights (BWs) of 23 ± 0.1 kg and ages of 50 ± 5 days, were kept in individual pens and fed a diet composed of 6% Cynodon ssp. hay and 94% concentrate and subjected to four treatments: CON without inclusion of additives, addition of ACL 5 g/kg of dry matter (DM), addition of CCL 6.3 g/kg of DM, and addition of BZA 5 g/kg of DM. There was no effect of treatment or interaction with time on blood parameters (p > 0.050), and performance characteristics, morphometry of ruminal papillae, and scores of cecum and rumen lesions were not affected by the addition of additives to the diet (p > 0.050). Greater urinary acidification was observed in animals from CCL and ACL treatments (p = 0.033). Calcium chloride acidified the urinary pH and can be used instead of ammonium chloride at a concentration of 0.63% based on DM, when this is the objective.

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This study aimed to evaluate the inclusion of chromium propionate or calcium salts of palm oil in ewes' diet during the final third of gestation and lactation on progeny performance, carcass characteristics, non-carcass components, and bone density. Forty-three ewe, Santa Inês and Dorper breed, three ± one-year-old, and body weight 57 ± 10 kg were used. The experimental design was in casual blocks in three treatments, CTL treatment (n = 15) with starch from corn; CR (n = 15) diet CTL plus chromium propionate; PF (n = 13) diet CTL plus calcium salts of palm oil. After weaning, 23 male lambs from these ewes were confined in individual stalls, with the same diet for 60 days, slaughtered. The data were analyzed using the SAS program, PROC GLM, and compared the means using Tukey's test at 5% probability. The maternal diet did not alter the dry matter intake, feeding efficiency, and average daily weight gain. Therefore, weights (weaning and slaughter) and carcass yield were higher for CR and PF groups than for CTL (P < 0.05). The treatment did not influence the loin eye area and fat thickness (P > 0.05). The spleen and the respiratory tract were smaller for PF and larger for CTL (P < 0.05). Leg weight was higher for CR. The perimeter and depth of the shank for the CR and PF lambs were higher, indicating an effect of maternal nutrition in this commercial cut. The CR group had a smaller epiphysis measurement and femur length than the CTL group. We concluded that the fetal programming effect in ewes fed with Cr propionate and Ca salts of palm oil benefited the progeny by increasing their body weight, better carcass yield, and a higher proportion of prime cuts.

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The impact of growth rate (GR) and finishing regime (FR) on growth and meat quality traits of Angus x Nellore crossbred steers, harvested at a constant body weight (530 ± 20 kg) or time on feed (140 days), was evaluated. Treatments were: 1) feedlot, high GR; 2) feedlot, low GR; 3) pasture, high GR and 4) pasture, low GR. Live body composition, carcass and meat quality traits were evaluated. High GR had greater impact on muscle and fat deposition in feedlot-finished, but not in pasture-finished animals. Feedlot animals had higher Longissimus muscle area, backfat thickness, meat luminosity and tenderness when compared to pasture groups. Moreover, pasture- and feedlot-finished animals with similar GR did not differ in the chromatic attributes of non-aged meat, regardless of endpoint. Thus, GR appeared to be the main factor driving beef chromatic parameters, while FR had a major impact on achromatic attributes and tenderness of meat.

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Thirty-six Nellore steers at 20 months of age on average and initial body weight of 360 kg, fed ad libitum for 78 days and two levels of feed restriction for 58 days and posterior ad libitum feeding for 78 days were used to estimate body composition using the methods of indirect deuterium oxide or the 9th-10th-11thribs cut. The body water content was calculated with equations established for Nellore steers. The chemical body composition was different for the ether extract content. The animals subjected to feed restriction presented higher body fat content when estimated by deuterium than by the rib cut. The deuterium oxide or 9th-10th-11thribs cut methods used for body composition determination were effective to estimate body contents for animals fed ad libitum, however, not for animals on feed restriction. Comparatively, the indirect method of deuterium oxide was better than the 9th-10th-11thribs cut method to estimate body composition in Nellore steers submitted to feed restriction; however, both methods were similar in animals fed ad libitum.(AU)

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OBJECTIVE: This work was carried out to evaluate the effects of zilpaterol hydrochloride (ZH) and ractopamine hydrochloride (RH) combined with immunocastration on the welfare traits of feedlot Nellore cattle. METHODS: Ninety-six Nellore males (average body weight [BW] = 409±50 kg; average 20 mo of age) were divided into two groups according to BW; half of the animals in each group received two doses of an immunocastration (ImC) vaccine in a 30 day interval, and the other half did not receive the vaccine (NoC). Afterward, the animals were housed and fed a common diet for 70 days. Then, they were split into three groups and fed one of the following diets for 30 additional days: control (CO) diet, with no ß-AA; ZH diet, containing 80 mg/d ZH; and RH diet, containing 300 mg/d RH. Welfare traits were assessed by monitoring body surface temperature using infrared thermography (IRT) and plasma cortisol and temperament measurements. RESULTS: There was no interaction between sexual condition and diet for any trait. The ImC and NoC groups did not differ in rectal and ocular temperatures. The ImC animals had higher flight speeds (p = 0.022) and tended to have higher cortisol levels (p = 0.059) than the NoC animals. Animals fed ZH and RH did not differ in cortisol levels, respiratory rate, rectal temperature, temperature measured by IRT, or temperament behaviour. CONCLUSION: The ImC animals showed a less stable temperament during handling practices than NoC, whereas ZH and RH supplementation had no adverse effects on animal welfare.

RESUMO

Thirty-six Nellore steers at 20 months of age on average and initial body weight of 360 kg, fed ad libitum for 78 days and two levels of feed restriction for 58 days and posterior ad libitum feeding for 78 days were used to estimate body composition using the methods of indirect deuterium oxide or the 9th-10th-11thribs cut. The body water content was calculated with equations established for Nellore steers. The chemical body composition was different for the ether extract content. The animals subjected to feed restriction presented higher body fat content when estimated by deuterium than by the rib cut. The deuterium oxide or 9th-10th-11thribs cut methods used for body composition determination were effective to estimate body contents for animals fed ad libitum, however, not for animals on feed restriction. Comparatively, the indirect method of deuterium oxide was better than the 9th-10th-11thribs cut method to estimate body composition in Nellore steers submitted to feed restriction; however, both methods were similar in animals fed ad libitum.

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Functional oils are known for their compounds with antioxidant, antimicrobial and anti-inflammatory properties, and are used in ruminant nutrition as alternatives to chemicals in order to improve performance. This study aimed to compare the influence of castor and cashew nut shell oils with pure organic selenium (hydroxy-selenomethionine) plus vitamin E, which are known and well-stablished antioxidants, on the performance traits, shelf life and microbial quality of the meat, physiological functions and oxidative stress control of lambs. Thirty-two Dorper x Santa Ines lambs (initial bodyweight of 22.42 ± 3.9 kg and 60 days of age) were submitted to a diet consisting of Cynodon dactylon hay (6%) and concentrate (94%). The animals were divided into four treatments: control, without additives; functional oils (FO), 0.50 g/kg DM of castor and cashew nut shell oils; hydroxy-selenomethionine and vitamin E (SeE), 0.50 mg/kg of organic selenium and 100 IU/kg DM of vitamin E; FO plus SeE, at the same doses as the other groups. Blood samples were collected after 1, 30 and 53 days on feed. After 54 days, the lambs were slaughtered and rumen health, carcass and meat traits, shelf life, and microbiological quality were evaluated. There were no differences in performance or carcass traits. A higher muscle and serum Se concentration (p < 0.0001), lower lipid peroxidation in meat during display (p < 0.0001), and a lower count of psychrotrophic microorganisms on day 5 were observed in the SeE and FO plus SeE groups. The treatments reduced the counts of Enterobacteriaceae, and Staphylococcus spp. FO animals showed higher GSH-Px activity on day 30, while the peroxidase activity was higher in FO plus SeE animals (p = 0.035). SeE and FO plus SeE animals had lower serum ALT and AST levels. Functional oils improved the microbiological quality of meat. Hydroxy-selenomethionine and vitamin E prevented oxidative stress, lipid peroxidation, and microbial spoilage.

RESUMO

The aim of this study was determine the energy and protein requirements for maintenance and gain of Nellore steers. Thirty six Nellore steers with an average weight and age of 359±13 kg and 20 months at the beginning of the trial were individually fed for 56. The steers were fed the same diet (76.43% TDN and 13.62% CP) in three levels of dry matter (DM) intake, ad libitum, 75 g DM/kg BW0.75 and 60 g DM/kg BW0.75. The initial and final body composition was estimated with the marker deuterium oxide that allowed repeated water estimate in the same animal. Deuterium in blood samples was analyzed by mass spectrometry. The effects of intake levels, comparison of intercept and slope among feeding level, and equations were evaluated by the analysis of variance, adopting P<0.05 as a significant level. The net energy for maintenance was 75 kcal/kg EBW 0.75 or 70 kcal/kg BW 0.75. The net energy for gain for steers with 350 to 450 kg weight was 5.1 to 6.1Mcal. The efficiency of energy utilization for maintenance, km, was 0.7492 and for weight gain, kg, was 0.3404. The metabolizable protein requirement for maintenance was 4.32 * BW0.75and the net protein for gain was estimated with the equation NPg= (254.68*EBWG) (29.38*RE). The technique of deuterium oxide marker used to estimate energy and protein requirement for maintenance and weight gain at Nellore steers confirm the hypothesis presented in NRC, that NEmis lower than the requirement for taurine cattle. On the other hand, the reverse was true for the NP requirement for maintenance and for weight gain. We consider that indirect method using D2O for estimate body composition in zebu cattle was suitable to determine nutrient requirements.(AU)

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The aim of this study was determine the energy and protein requirements for maintenance and gain of Nellore steers. Thirty six Nellore steers with an average weight and age of 359±13 kg and 20 months at the beginning of the trial were individually fed for 56. The steers were fed the same diet (76.43% TDN and 13.62% CP) in three levels of dry matter (DM) intake, ad libitum, 75 g DM/kg BW0.75 and 60 g DM/kg BW0.75. The initial and final body composition was estimated with the marker deuterium oxide that allowed repeated water estimate in the same animal. Deuterium in blood samples was analyzed by mass spectrometry. The effects of intake levels, comparison of intercept and slope among feeding level, and equations were evaluated by the analysis of variance, adopting P<0.05 as a significant level. The net energy for maintenance was 75 kcal/kg EBW 0.75 or 70 kcal/kg BW 0.75. The net energy for gain for steers with 350 to 450 kg weight was 5.1 to 6.1Mcal. The efficiency of energy utilization for maintenance, km, was 0.7492 and for weight gain, kg, was 0.3404. The metabolizable protein requirement for maintenance was 4.32 * BW0.75and the net protein for gain was estimated with the equation NPg= (254.68*EBWG) – (29.38*RE). The technique of deuterium oxide marker used to estimate energy and protein requirement for maintenance and weight gain at Nellore steers confirm the hypothesis presented in NRC, that NEmis lower than the requirement for taurine cattle. On the other hand, the reverse was true for the NP requirement for maintenance and for weight gain. We consider that indirect method using D2O for estimate body composition in zebu cattle was suitable to determine nutrient requirements.

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OBJECTIVE: The objective of this experiment was to compare conventional antioxidants and plant extracts for oxidative stress control in lambs fed a high-concentrate diet. METHODS: Forty-eight male Dorper×Santa Ines lambs with an initial weight of 20±1.49 kg and 60 days of age, were used to evaluate the effects of feeding a combination of Macleaya cordata and Magnolia officinalis plant extracts (0 vs 320 mg/kg dry matter [DM]) in combination with selenium+vitamin E (0 vs 100 IU/kg DM of vitamin E and 0.1 mg/kg DM of selenium) in a completely randomized block design in a 2×2 factorial arrangement. The animals were housed in individual pens and received a high-concentrate diet consisting of 80% whole corn and 20% protein pellet for 60 days. The animals were weighed at the beginning of the experiment and every 14 days for performance monitoring. Three blood samplings were performed during the experimental period for the evaluation of oxidative and protein parameters. RESULTS: The treatments with vitamin E and selenium as additives had a positive influence on final weight, daily weight gain, carcass weight, and selenium content in longissimus muscle (p = 0.01). Plant extracts tended to improve final weight (p = 0.064) and daily weight gain (p = 0.059), showing similar effect as selenium and vitamin E. There was no effect of treatment on blood proteins, indicating that the animals were healthy throughout the experiment. CONCLUSION: The use of plant extracts had a similar effect as the addition of selenium and vitamin E, with dietary inclusion of additives resulting in better performance of lambs but both supplements did not have strong influence on oxidative stress.

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This study was carried out to evaluate the effect of a blend of additives (choline, methionine, selenium, and organic zinc) on performance, feed efficiency, rumen parameters, and carcass traits of Nellore heifers finished with roughage-free diet. Nellore heifers (n = 36; average BW = 244±24.1 kg; average 24 months of age) were maintained in a feedlot system for 86 d. Heifers were separated into two groups: control and additive. Heifers in control group were fed a based diet composed of 850 g kg−1 corn grain and 150 g kg−1 of a mineral-vitamin-protein pellet. The additive group was fed a diet supplemented with a blend of choline, methionine, selenium, and organic zinc at 1,667, 4,000, 1, and 24.37 mg kg−1 of the diet dry matter, respectively. The animals were allotted to 18 pens (two heifers/pen), with nine pens per treatment. Heifers were weighed, blood samples were collected, ultrasonography examinations were performed periodically, and hot carcass and papillae samples were taken at slaughter. Data were analyzed as a completely randomized design. The model included the fixed effect of treatments (control and additive). Additive supplementation did not change dry matter intake, performance, or feed efficiency. There was no effect of additives on muscle or fat tissue deposition. Consequently, no changes in hot carcass weight and dressing were found. Overall, additive inclusion did not alter blood parameters, blood electrolyte balance, and rumen traits. Nellore heifers finished with roughage-free diets have no improvement on production traits nor in their rumen health by supplementation with a blend of choline, methionine, selenium, and organic zinc.(AU)

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For this research 48 male lambs were divided in randomized blocks in a factorial design, having as factors sexual condition (castrated or uncastrated) and time on feed (36 or 78 days). High grain diet was monitored daily to measure the performance of the animal nutrition. The characteristics of the carcass and meat were taken for the fatty acids profile and sensorial analysis. The effect of the factors as sexual condition and time on feed, and the interaction between them, were evaluated by analysis of variance using the GLM procedure of SAS software and the treatment averages were compared by Student"s T test. The uncastrated animals presented greater weight gain and dry matter intake, better feed efficiency, and larger loin area. More time on feed resulted in higher weight at slaughter. Parameters such as pH, color, meat tenderness and sensorial attributes were not affected by treatments. For the fatty acid profile there was effects and interactions between sexual condition and time on feed. It is concluded that castration should not be used when the animal is young and slaughtered and feed intensively, but neutering can be interesting to improve the fatty acid profile of the meat.(AU)

No experimento realizado, foram utilizados 48 cordeiros machos divididos em blocos casualizados, em esquema fatorial, sendo tais fatores: a condição sexual (castrado ou não castrado) e tempo de confinamento (36 ou 78 dias). Uma dieta rica em grãos foi ofertada e controlada diariamente para medir o desempenho da nutrição animal, as características da carcaça e da carne foram avaliadas, e foi feita análise sensorial. A condição sexual e o tempo em confinamento, bem como a interação entre eles, foram avaliados por análise de variância, utilizando o procedimento GLM do software SAS e as médias dos tratamentos foram comparadas pelo teste t de estudante (p 0,05). Os animais não castrados apresentaram maior ganho de peso e consumo de matéria seca. Eles também tiveram uma melhor eficiência alimentar e área de lombo. Mais tempo no confinamento resultou em maior peso ao abate. Parâmetros como pH, cor, maciez da carne e atributos sensoriais não foram afetados pelos tratamentos. Para o perfil de ácidos graxos, houve efeitos e as interações entre condição sexual e tempo de confinamento. Concluiu-se que a castração não deve ser usada quando o animal é novo e criado em sistema intensivo, mas a castração pode ser interessante para melhorar o perfil de ácidos graxos da carne.(AU)

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For this research 48 male lambs were divided in randomized blocks in a factorial design, having as factors sexual condition (castrated or uncastrated) and time on feed (36 or 78 days). High grain diet was monitored daily to measure the performance of the animal nutrition. The characteristics of the carcass and meat were taken for the fatty acids profile and sensorial analysis. The effect of the factors as sexual condition and time on feed, and the interaction between them, were evaluated by analysis of variance using the GLM procedure of SAS software and the treatment averages were compared by Student"s T test. The uncastrated animals presented greater weight gain and dry matter intake, better feed efficiency, and larger loin area. More time on feed resulted in higher weight at slaughter. Parameters such as pH, color, meat tenderness and sensorial attributes were not affected by treatments. For the fatty acid profile there was effects and interactions between sexual condition and time on feed. It is concluded that castration should not be used when the animal is young and slaughtered and feed intensively, but neutering can be interesting to improve the fatty acid profile of the meat.

No experimento realizado, foram utilizados 48 cordeiros machos divididos em blocos casualizados, em esquema fatorial, sendo tais fatores: a condição sexual (castrado ou não castrado) e tempo de confinamento (36 ou 78 dias). Uma dieta rica em grãos foi ofertada e controlada diariamente para medir o desempenho da nutrição animal, as características da carcaça e da carne foram avaliadas, e foi feita análise sensorial. A condição sexual e o tempo em confinamento, bem como a interação entre eles, foram avaliados por análise de variância, utilizando o procedimento GLM do software SAS e as médias dos tratamentos foram comparadas pelo teste t de estudante (p 0,05). Os animais não castrados apresentaram maior ganho de peso e consumo de matéria seca. Eles também tiveram uma melhor eficiência alimentar e área de lombo. Mais tempo no confinamento resultou em maior peso ao abate. Parâmetros como pH, cor, maciez da carne e atributos sensoriais não foram afetados pelos tratamentos. Para o perfil de ácidos graxos, houve efeitos e as interações entre condição sexual e tempo de confinamento. Concluiu-se que a castração não deve ser usada quando o animal é novo e criado em sistema intensivo, mas a castração pode ser interessante para melhorar o perfil de ácidos graxos da carne.

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ABSTRACT: Additives are used in high concentrate diets to prevent metabolic disorders in cattle. This study was designed to evaluate the effect of calcium sources and monensin on the control of ruminal acidosis in Nellore cattle that were abruptly shifted to a high (92.3%) concentrate diet. Eight cannulated steers were randomly assigned to two contemporary 4x4 Latin square. Treatments involved the addition of a calcium source, either limestone (LI) or a product derived from calcareous algae (CA), to the basic diet with or without the presence of monensin. Calcareous alga (Lithothamnium calcareum) is a natural and renewable product and a source of calcium carbonate. The quantity of added limestone, calcareous algae and monensin was 7.1g kg-1, 7.4g kg-1 and 30mg kg-1 DM, respectively. There was no effect of calcium source (P=0.607) or monensin (P=0.294) on feed intake or on the concentration of short chain fatty acids. Treatments with calcareous algae resulted in a higher mean ruminal pH (P=0.039), a shorter amount of time with the ruminal pH under 5.2 (P<0.001) and a better control of blood pH (P=0.006). Treatments with monensin also resulted in a shorter amount of time with the ruminal pH below 5.2 (P=0.023). Calcareous algae were shown to be effective in controlling adverse changes in the rumen and in blood variables for Nellore cattle that were subjected to an abrupt change to a high concentrate diet.

RESUMO: Os aditivos são amplamente utilizados em dietas com elevada proporção de concentrado a fim de prevenir distúrbios metabólicos em bovinos. Este estudo foi desenvolvido para avaliar o efeito das diferentes fontes de cálcio, com ou sem monensina sódica na dieta, no controle da acidose ruminal de bovinos Nelore, recebendo, de forma abrupta, uma dieta com elevada proporção (92,3%) de concentrado. Oito bovinos portadores de cânulas ruminais foram distribuídos em um delineamento quadrado latino (4x4) duplo contemporâneo. Os tratamentos foram a adição de diferentes fontes de cálcio, calcário calcítico (LI) ou produto a base de alga calcária (CA), com (WIMO) ou sem (WOMO) a presença de monensina, à dieta base. A alga calcária, Lithothamnium calcareum, é um produto natural, renovável e fonte de carbonato de cálcio, podendo ser uma alternativa no controle desses distúrbios. A inclusão de LI, CA e monensina foi de 7,1g kg-1, 7,4g kg-1 e 30mg kg-1 MS, respectivamente. Não houve efeito das fontes de cálcio e da monensina sobre o consumo alimentar e concentração total dos ácidos graxos de cadeia curta. Os tratamentos com AC resultaram em maior pH ruminal médio (P=0,039), menor tempo com pH ruminal abaixo de 5,2 (P<0,001) e um maior pH sanguíneo (P=0,006). Os tratamentos com monensina apresentaram menor tempo com pH ruminal abaixo de 5,2 (P=0,023). O produto a base de alga calcária foi eficiente no controle das mudanças adversas das variáveis ruminais e sanguíneas em bovinos Nelore submetidos a mudanças abruptas para dietas com elevada proporção de concentrado.

RESUMO

Additives are used in high concentrate diets to prevent metabolic disorders in cattle. This study was designed to evaluate the effect of calcium sources and monensin on the control of ruminal acidosis in Nellore cattle that were abruptly shifted to a high (92.3%) concentrate diet. Eight cannulated steers were randomly assigned to two contemporary 4x4 Latin square. Treatments involved the addition of a calcium source, either limestone (LI) or a product derived from calcareous algae (CA), to the basic diet with or without the presence of monensin. Calcareous alga (Lithothamnium calcareum) is a natural and renewable product and a source of calcium carbonate. The quantity of added limestone, calcareous algae and monensin was 7.1g kg-1, 7.4g kg-1 and 30mg kg-1 DM, respectively. There was no effect of calcium source (P=0.607) or monensin (P=0.294) on feed intake or on the concentration of short chain fatty acids. Treatments with calcareous algae resulted in a higher mean ruminal pH (P=0.039), a shorter amount of time with the ruminal pH under 5.2 (P 0.001) and a better control of blood pH (P=0.006). Treatments with monensin also resulted in a shorter amount of time with the ruminal pH below 5.2 (P=0.023). Calcareous algae were shown to be effective in controlling adverse changes in the rumen and in blood variables for Nellore cattle that were subjected to an abrupt change to a high concentrate diet.(AU)

Os aditivos são amplamente utilizados em dietas com elevada proporção de concentrado a fim de prevenir distúrbios metabólicos em bovinos. Este estudo foi desenvolvido para avaliar o efeito das diferentes fontes de cálcio, com ou sem monensina sódica na dieta, no controle da acidose ruminal de bovinos Nelore, recebendo, de forma abrupta, uma dieta com elevada proporção (92,3%) de concentrado. Oito bovinos portadores de cânulas ruminais foram distribuídos em um delineamento quadrado latino (4x4) duplo contemporâneo. Os tratamentos foram a adição de diferentes fontes de cálcio, calcário calcítico (LI) ou produto a base de alga calcária (CA), com (WIMO) ou sem (WOMO) a presença de monensina, à dieta base. A alga calcária, Lithothamnium calcareum, é um produto natural, renovável e fonte de carbonato de cálcio, podendo ser uma alternativa no controle desses distúrbios. A inclusão de LI, CA e monensina foi de 7,1g kg-1, 7,4g kg-1 e 30mg kg-1 MS, respectivamente. Não houve efeito das fontes de cálcio e da monensina sobre o consumo alimentar e concentração total dos ácidos graxos de cadeia curta. Os tratamentos com AC resultaram em maior pH ruminal médio (P=0,039), menor tempo com pH ruminal abaixo de 5,2 (P 0,001) e um maior pH sanguíneo (P=0,006). Os tratamentos com monensina apresentaram menor tempo com pH ruminal abaixo de 5,2 (P=0,023). O produto a base de alga calcária foi eficiente no controle das mudanças adversas das variáveis ruminais e sanguíneas em bovinos Nelore submetidos a mudanças abruptas para dietas com elevada proporção de concentrado.(AU)

Assuntos

RESUMO

The aims of this study were to evaluate the use of infrared thermography (IRT) images as a tool for monitoring body surface temperature and to study its relationship with residual feed intake (RFI) in Nellore cattle. We also evaluated IRT as an indicator of feed efficiency in Bos indicus cattle. In this study, 144 Nellore steers were fed high-concentrate diets for 70 days to evaluate feedlot performance. We examined nine animals classified as high RFI and nine animals classified as low RFI by measuring rectal temperature (RT), respiratory frequency (RF), and IRT in the front, eye, ocular area, cheek, flank, ribs, rump, and front feet. The measurements were taken at 0700, 1200, and 1600 hours. The IRT temperatures measured at the eye, cheek, flank, ribs, rump, and front feet were positively associated with RF and RT. These results indicate that increases in the temperatures are associated with increased RF and RT. There was an effect in the RFI group in the front region where IRT correlates with RT. The front IRT for high-RFI cattle was lower (P < 0.01) than that for low-RFI cattle. The higher skin temperature measured by IRT for animals in the RFI group may be related to improved efficiency of thermoregulatory mechanisms because the RT remained lower in the low-RFI group. IRT can be used in the head for studies related to RFI in beef cattle.

Assuntos

RESUMO

Vinte e dois cordeiros machos não castrados, Dorper x Santa Inês, com aproximadamente 90 dias de idade e peso vivo médio inicial de 27,0±4,4kg, foram alimentados com uma dieta com elevada proporção de concentrado com 20% de pelete proteico-mineral (Grano Entero(r)), 5% de feno de capim coast-cross e 75% de milho, na forma de milho grão inteiro (MGI), milho grão moído (MGM) ou milho grão úmido (MGU), para avaliação de desempenho no confinamento por um período de 14 dias de adaptação às dietas e às instalações e de 65 dias de confinamento. Em seguida, os animais foram abatidos com peso vivo médio final (PVF) de 47,97±5,13kg e o conteúdo gástrico foi avaliado para quantificação de protozoários, e foi realizada avaliação papilar. O delineamento experimental foi o de blocos casualizados. Não houve diferença entre os tratamentos (P>0,05) quanto ao ganho de peso médio diário, eficiência alimentar, ingestão diária de matéria seca, características da carcaça e da carne. Os animais tratados com MGI tiveram maior conteúdo gástrico, menor pH ruminal, maior AP (% da superfície de absorção) e maior área papilar em comparação com os outros tratamentos. Os animais tratados com MGI tiveram melhores resultados para o peso final, mas para os demais parametros estudados não foi observada diferença.

Twenty-two males not neutered, Dorper x St. Agnes, with approximately 90 days of age and average live weight of 27.0±4.4kg were fed with a diet wich contained high concentrate with 20% protein pellet-mineral (Grano Entero (r)), 5% grass hay coast-cross and 75% corn in the form of whole kernel corn (MGI), ground corn grain (MGM) or high moisture corn (MGU) for performance evaluation in confinement for a period of 14 days of adaptation to the diets and facilities and 65 days of confinement. Then the animals were slaughtered at average final weight (PVF) of 47.97±5.13kg and gastric content was evaluated for quantification of protozoa, and a papillary review was conducted. The experimental design was in randomized blocks. There was no difference between treatments (P>0.05) for average daily weight gain, feed efficiency, daily dry matter intake, carcass characteristics and meat. MGI-treated animals had higher gastric contents, the lower ruminal pH greater AP (% of surface absorption) and the larger papillary area was compared with other treatments. Animals treated with MGI had better results for the final weight gain, but for the other parameters studied, no difference was observed.