Effects of monensin and a blend of magnesium oxide on performance, feeding behavior, and rumen morphometrics of Zebu beef cattle fed high-starch diets.

This study aimed to evaluate the effects of a blend of different sources of magnesium oxide associated or not with monensin, on productive, ruminal, and nutritional parameters of steers. Eighty-four Nellore steers with an initial body weight (BW) of 367.3 ±â€…37.9 kg were allocated to one of 28 pens, with three steers per pen. Each pen was considered an experimental unit. Using a completely randomized design with a 2 × 2 factorial arrangement, the following treatments were assigned to each pen: 1) Control (CON)-a basal diet without additive inclusion; 2) Magnesium oxide blend (MG)-basal diet plus a magnesium-based product (pHix-up, Timab Magnesium, Dinard, France) provided at 0.50% of dry matter (DM); 3) Monensin (MON)-basal diet plus 25 mg/ kg of DM of sodium monensin (Rumensin, Elanco Animal Health, Greenfield, IN); and 4) MG association with MON-basal diet plus MG + MON, at the same doses of the individual treatments. The experimental period lasted 100 d. Blood samples were collected on days 0, 13, and 70 to determine d-lactate levels. Daily feed intake was recorded, and animal ingestive behavior was visually observed on days 66 and 67. On day 70, skeletal muscle tissue samples were obtained through biopsy for gene expression analysis. At the end of the experimental period, carcass ultrasonography was conducted. Subsequently, the steers were slaughtered, and rumen epithelium samples were collected for morphometric analysis. The use of monensin, of magnesium oxide blend, and their interactions, were treated as fixed effects, while the pens were considered as a random effect. Statistical differences were considered when P < 0.05. Steers-fed MG-containing diets consumed approximately 0.6 kg more DM per day than those fed diets without this additive (P = 0.01; 11.3 vs. 11.9 kg/d). The inclusion of MG in the diet increased (P = 0.02) the average daily gain. There was a greater Longissimus muscle area (LMA) and LMA per 100 kg of BW (P ≤ 0.03) for steers-fed diets with MG. Steers-fed MON exhibited reduced mRNA expression of the Atrogin-1 and mTOR compared to steers-fed MG + MON diets (MON × MG: P ≤ 0.04). Steers-fed MON had 6.9% greater feed efficiency (P = 0.02). Papillae width was lesser for CON than other treatments (MON × MG: P = 0.02). In conclusion, the magnesium oxide blend improved performance and carcass traits in high-energy feedlot diets, while monensin enhanced feed efficiency, suggesting potential for their use as alternatives or complements in beef cattle nutrition.

Supplementing narasin or monensin to control coccidiosis in naturally infected calves.

This experiment compared narasin and monensin as anticoccidials for calves naturally infected with Eimeria spp. Twenty-four weaned, non-castrated male calves (Bos indicus × B. taurus cross) were assigned to this experiment (days -8 to 42). All calves were infected by Eimeria spp. according to oocyst count per gram (OPG) from fecal samples collected on days -8 and -7 (average 1,059 ±â€…101 oocysts/g). Calves were housed in individual pens, received corn silage, mineral mix, and water for ad libitum consumption, in addition to a grain-based supplement at 200 g/head daily. Fecal samples were collected on days -2 and -1 for OPG, and results averaged as initial OPG value. Calves were blocked according to initial OPG into eight blocks of three calves each, ranked within each block according to body weight (BW) recorded on day -1, and assigned to receive narasin (NAR; 0.8 mg/kg of BW), monensin (MON; 1 mg/kg of BW), or no ionophore (CON; negative control). Ionophores were added to the grain-based supplement, and offered from days 0 to 42 of the experiment. Calf BW was recorded on days 7, 14, 21, 28, 35, and 42. Fecal samples were collected on days 6 and 7, 13 and 14, 20 and 21, 26 and 27, 34 and 35, and 41 and 42 for OPG analysis, and results from samples collected on consecutive days were averaged. Aliquoted fecal samples were also pooled across calves from the same treatment and collection days, and used to determine the prevalence of individual species of Eimeria. No treatment effects were detected (P ≥ 0.51) for calf BW or growth rate. A treatment × day interaction was detected (P < 0.01) for OPG, as NAR and MON calves had less (P < 0.01) OPG compared with CON calves beginning on day 7. The OPG was also less (P ≤ 0.03) in MON compared with NAR calves on days 7, 14, and 28, but did not differ (P ≥ 0.48) on days 21, 35, and 42. The anticoccidial efficacy of NAR and MON did not differ (P ≥ 0.16) when calculated across all Eimeria spp., or according to prevalence of E. bovis and E. alabamensins. A treatment × day interaction was detected (P = 0.04) for anticoccidial efficacy to E. alabamensis, which was greater (P < 0.01) in MON calves on days 7 and 14 and did not differ (P ≥ 0.40) afterward. Collectively, both ionophores were similarly effective in controlling coccidiosis upon completion of the 42-d study, although the anticoccidial effects of monensin were noted earlier in the experiment. Nonetheless, these results corroborate narasin as an efficient anticoccidial ionophore for naturally infected calves.

Copper in Gynecological Diseases.

Copper (Cu) is an essential micronutrient for the correct development of eukaryotic organisms. This metal plays a key role in many cellular and physiological activities, including enzymatic activity, oxygen transport, and cell signaling. Although the redox activity of Cu is crucial for enzymatic reactions, this property also makes it potentially toxic when found at high levels. Due to this dual action of Cu, highly regulated mechanisms are necessary to prevent both the deficiency and the accumulation of this metal since its dyshomeostasis may favor the development of multiple diseases, such as Menkes' and Wilson's diseases, neurodegenerative diseases, diabetes mellitus, and cancer. As the relationship between Cu and cancer has been the most studied, we analyze how this metal can affect three fundamental processes for tumor progression: cell proliferation, angiogenesis, and metastasis. Gynecological diseases are characterized by high prevalence, morbidity, and mortality, depending on the case, and mainly include benign and malignant tumors. The cellular processes that promote their progression are affected by Cu, and the mechanisms that occur may be similar. We analyze the crosstalk between Cu deregulation and gynecological diseases, focusing on therapeutic strategies derived from this metal.

Effects of monensin in supplements for beef cattle in tropical grazing systems during the rainy season.

Two experiments were carried out to evaluate the effect of monensin in supplements for grazing heifers. In experiment I, treatments consisted of protein supplements (low intake - 0.5 kg/animal/day and high intake - 1.0 kg/animal/day) associated or not with monensin. Animal performance, nutrient intake, and digestibility were evaluated. Forty crossbred heifers with an initial body weight (BW) of 213.8 ± 4.5 kg were used. There was no difference in average daily gain between treatments (average of 0.588 kg/animal/day). There was no interaction between monensin and supplements for intake parameters and digestibility. Dry matter (DM) intake was equal between treatments (~ 2% of BW). However, there was a reduction in pasture intake with the high-intake supplement. In experiment II, treatments consisted of two types of supplements (protein or mineral) associated or not with monensin. The variables analyzed were productive performance, ingestive behavior, and thermal comfort, evaluated through the index of thermal stress for cows (ITSC). Forty crossbred heifers with a BW of 159.2 ± 1.3 kg were used. The type of supplement did not influence the performance of the animals. However, monensin promoted greater weight gain in the animals (110 g/animal/day). There was an interaction effect between supplementation and monensin addition on behavioral activities, except for idle time. The inclusion of monensin in the protein supplement reduced the grazing time. The ITSC value influenced the activities of ingestive behavior, and the increase of this index reduced the grazing time in all treatments. Forage quality influences the response to monensin use, and the addition of monensin in supplements for grazing cattle during the rainy season is recommended for forages with high CP content.

Residual effect of narasin on feed intake and rumen fermentation characteristics in Nellore steers fed forage-based diet.

This study aimed to evaluate the residual effect of narasin on intake and ruminal fermentation parameters in Nellore cattle fed a forage-based diet. Thirty rumen-cannulated Nellore steers [initial body weight (BW) = 281 ± 21 kg] were allocated to individual pens in a randomized complete block design, with 10 blocks and 3 treatments, defined according to the fasting BW at the beginning of the experiment. The animals were fed a forage-based diet containing 99% Tifton-85 haylage and 1% concentrate. Within blocks, animals were randomly assigned to one of three treatments: (1) forage-based diet without addition of narasin (CON; n = 10), (2) CON diet plus 13 mg of narasin/kg DM (N13; n = 10), or (3) CON diet plus 20 mg of narasin/kg DM (N20; n =10). The experiment lasted 156 d and was divided into two periods. The first period lasted 140 d and consisted of the daily supply of narasin. In the second period (last 16 d), the animals were not supplemented with narasin when the residual effect of the additive was evaluated. The treatments were evaluated by linear and quadratic orthogonal contrasts. The results were reported as least square means and the effect was considered significant when P ≤ 0.05. No treatment × day interaction was identified for dry matter intake (P = 0.27). There was a treatment × day (P ≤ 0.03) interaction after narasin removal for the molar proportion of acetate, propionate, ac:prop ratio, and ammonia nitrogen. The inclusion of narasin decreased linearly (P < 0.01) the molar proportion of acetate (P < 0.01), and this effect persisted until day 5 after narasin withdrawal (P < 0.01). Narasin inclusion linearly increased the molar proportion of propionate (P < 0.04), and linearly decreased (P < 0.01) ac:prop ratio up to 5 d after removing narasin from the diets. No treatment effects were observed (P > 0.45) on days 8 and 16 after the withdrawal. Narasin linearly decreased ammonia nitrogen up to 1 day after withdrawal (P < 0.01). In conclusion, the use of narasin for a prolonged period (140 d) resulted in a residual effect on rumen fermentation parameters after the removal of the additive from the diets.

Can phytogenic additives replace monensin sodium in beef cattle feeding?

Monensin sodium is one of the most common ionophores used in livestock feeding; however, ionophores are condemned by organized consumer groups. Bioactive compounds from plants found in the seasonally dry tropical forest have similar mechanisms of action as ionophores. The aim was to investigate the effects of replacing monensin sodium with phytogenic additives on the nutritional efficiency of beef cattle. Five 14-month-old Nellore bulls (average body weight 452.68 ± 42.60 kg) were used in the study. The experiment was designed as a 5 × 5 Latin Square (five treatments and five 22-day experimental periods). Within each period, 15 days were used for adaptation of animals to experimental conditions and 7 days for data collection. Bulls were fed a control diet (without additives), monensin (a diet containing monensin sodium 40% as a synthetic additive), and three diets containing phytogenic additives prepared from Anadenanthera macrocarpa (Benth) Brenan, Mimosa tenuiflora (Willd) Poiret, or Prosopis juliflora (Sw.) DC. Nutritional efficiency was assessed through feed intake, nutrient digestibility, feeding behavior, and hematological parameters. Monensin and phytogenic additives did not influence (P > 0.05) feeding behavior or hematological parameters, but the nutrient intake was highest for bulls supplemented phytogenic additives (P < 0.05). Monensin supplementation did not influence (P > 0.05) feed intake. The phytogenic additives and monensin sodium increased (P < 0.05) the nutrient digestibility. Therefore, the phytogenic additives from P. juliflora, A. macrocarpa, and M. tenuiflora can be recommended to enhance the nutritional efficiency of confined Nellore cattle.

Associative effect of essential oils, tannins, and sodium monensin on the performance of steers finished in feedlot / Efeito associativo de óleos essenciais, taninos e monensina sódica sobre o desempenho de novilhos terminados em confinamento

The objective was to evaluate the productive performance, ingestive behavior, apparent digestibility of the diet and carcass traits of beef steers finished in feedlot under the effect of including tannins and essential oils (TAN+EO) alone or combined with sodium monensin (MO) in the feed. For this purpose, 30 ½ blood Angus steers from the same herd, with an average age of 12 months and an average initial body weight of 367.8 kg were used. The experimental design was randomized blocks, consisting of three treatments: MO - diet with sodium monensin (25 mg kg DM-1); TAN+EO - diet with tannins and essential oils (1.5 g kg DM-1); and MO+TAN+EO - diet with sodium monensin + tannins and essential oils (25 mg kg DM-1 + 1.5 g kg DM-1), with five repetitions, where each repetition was represented by a stall with two animals. Diets were formulated and consisted of a mixture of 40% corn silage and 60% concentrate, which was fed to the animals twice a day, at 06h00 am and 05h30 pm. There was no difference (P>0.05) in average daily weight gain of animals between treatments, with an average of 1.392 kg day-1. Carcass yield was higher for animals that received the compound of essential oils and tannins (55.72%), compared to animals fed the combination of tannins, essential oils and monensin (54.54%) but did not differ from those supplemented with sodium monensin alone (55.58%). Supplementation with essential oils and tannins improved the apparent digestibility of the diet, however, did not promote changes in the ingestive behavior and carcass traits of steers. The combination of essential oils and tannins with sodium monensin did not show a potentiated effect on animal performance, digestibility of DM, digestive and ingestive behavior and carcass traits of feedlot finished steers compared to the combined use of essential oils with tannins.(AU)

Objetivou-se avaliar o desempenho produtivo, o comportamento ingestivo, a digestibilidade aparente da dieta e as características de carcaça de novilhos de corte terminados em confinamento sob efeito da inclusão de taninos e óleos essenciais (TAN+OE) de forma isolada ou associada a monensina sódica (MO) na ração. Para tal utilizou-se 30 novilhos, ½ sangue Angus, provenientes de mesmo rebanho, com idade média de 12 meses e peso vivo médio inicial de 367,8 kg. O delineamento experimental foi o de blocos casualizados, constituído de três tratamentos sendo: MO - dieta com monensina sódica (25 mg kg MS-1); TAN+OE - dieta com taninos e óleos essenciais (1,5 g kg MS-1); e MO+TAN+OE - dieta com monensina sódica + taninos e óleos essenciais (25 mg kg MS-1 + 1,5 g kg MS-1), com cinco repetições, onde cada repetição foi representada por uma baia com dois animais. As dietas foram formuladas e constituídas por uma mistura de 40% de silagem de milho e 60% de concentrado, a qual foi fornecida aos animais duas vezes ao dia, às 06h00 e às 17h30 horas. Não ocorreu diferença (P>0,05) no ganho de peso médio diário dos animais entre os tratamentos, apresentando média de 1,392 kg dia-1. O rendimento de carcaça foi superior para os animais que receberam composto de óleos essenciais e taninos (55,72%), em relação aos animais que receberam a associação de taninos, óleos essências e monensina (54,54%) no entanto não diferiram dos suplementados com monensina sódica isolada (55,58%). A suplementação com óleos essenciais e taninos melhorou a digestibilidade aparente da dieta, entretanto, não promoveu alterações no comportamento ingestivo e nas características de carcaça de novilhos. A associação de óleos essenciais e taninos à monensina sódica não apresentou efeito potencializado no desempenho animal, digestibilidade da MS, comportamento digestivo e ingestivo e características de carcaça de novilhos terminados em confinamento frente ao uso de óleos essenciais com taninos.(AU)

Effects of antibiotic growth promoters and concentrate on intake, digestibility, degradability, and ruminal variables in beef steers / [Efeitos de antibióticos promotores de crescimento e do concentrado sobre o consumo, digestibilidade, degradabilidade e variáveis ruminais de novilhos de corte]

The objective of this study was to evaluate the addition of antibiotic growth promoters to concentrate on intake, digestibility, in situ degradability and ruminal variables in steers. Four steers in a Latin square design were fed hay (ad libitum), concentrate [10g kg-1 of body weight (BW)] and mineral mix (0.272g kg-1 of BW). The additives (0.75mg kg-1 of BW) were incorporated in the mineral mix as follows: Control (no antibiotics), lasalocid (LASA), salinomycin (SALI) or virginiamycin (VIRG). Antibiotic did not affect intake, pH, volatile fatty acids (VFA) and digestibility of dry matter (DM), organic matter, crude protein, ethereal extract, and non-fibrous carbohydrates. The LASA and SALI tended (P=0.09) to reduce the digestibility of neutral detergent fiber (NDF). The SALI and VIRG tended (P=0.09) to reduce the DM disappearance, and VIRG tended (P=0.06) to reduce the NDF disappearance in the rumen. The SALI and VIRG reduced the effective degradation and only SALI reduced the concentration of N-NH3 in the rumen. Thus, the antibiotics did not affect intake, pH, VFA and digestibility, but decreased the degradation of fiber and only SALI reduced the concentration of ammonia nitrogen (N-NH3) in the rumen.

O objetivo foi avaliar a adição de antibióticos promotores de crescimento ao concentrado sobre o consumo, digestibilidade, degradabilidade in situ e variáveis ruminais de novilhos. Quatro novilhos em um delineamento quadrado latino foram alimentados com feno (ad libitum), concentrado [10g kg-1 do peso corporal (PC)] e mistura mineral (0,272g kg-1 do PC). Os antibióticos (0,75mg kg-1 do PC) foram incorporados à ração: Controle (sem antibióticos), lasalocida (LASA), salinomicina (SALI) ou virginiamicina (VIRG). Os antibióticos não afetaram o consumo, pH, ácidos graxos voláteis (AGV) e digestibilidade da matéria seca (MS), matéria orgânica, proteína bruta, extrato etéreo e carboidratos não fibrosos. A LASA e a SALI tenderam (P=0,09) a reduzir a digestibilidade da fibra em detergente neutro (FDN). A SALI e a VIRG tenderam (P=0,09) a reduzir o desaparecimento da MS, e a VIRG tendeu (P=0,06) a reduzir o desaparecimento da FDN no rúmen. A SALI e a VIRG reduziram a degradação efetiva e somente a SALI reduziu a concentração de nitrogênio amoniacal (N-NH3) no rúmen. Assim, os antibióticos não afetaram o consumo, pH, AGV e digestibilidade, mas diminuiram a degradação da fibra e somente a SALI reduziu a concentração de N-NH3 no rúmen.

Narasin improves ewe milk yield efficiency and may affect performance of lambs

Adding ionophores to ruminant diets is a strategy to manipulate ruminal fermentation and improve milk yield. This study evaluates the effects of narasin supply to lactating ewes on dry matter intake (DMI), milk yield and composition, and performance of the lambs. Thirty lactating Santa Inês and Santa Inês × Dorper ewes fed a basal diet containing 50 % coastcross hay and 50 % concentrate were randomly assigned to two treatments: control (CON; without ionophores) or NAR (addition of 13 mg narasin kg-1 DM). From the 2nd to 10th week of lactation, DMI of ewes was determined, and once a week, their milk production and composition was measured over a 3-h interval. At the 10th week of lactation, lambs were weaned and their average daily gain (ADG) and starter DMI continued to be evaluated for two more weeks. Narasin supply did not affect weight and DMI of ewes. Ewes fed NAR had greater feed efficiency for milk production and displayed tendency for higher milk yield. Narasin supply reduced milk protein levels, but it did not affect other milk component levels. Ewes fed NAR had greater production of milk urea nitrogen and showed tendency for higher production of fat and total solids. Starter DMI of lambs was not affected by treatments; however, there was a tendency for greater weaning weight for NAR lambs. At the end of experiment, no differences were observed in the performance of lambs. The supply of 13 mg narasin kg-1 to lactating ewes improved milk yield efficiency and tended to increase the weaning weight of their lambs.(AU)

Effect of mixture of herbal plants on ruminal fermentation, degradability and gas production

Reducing livestock negative environmental impacts get great interest in last years. So, present study was carried out to determine the effect of adding different levels of mixture of thyme and celery versus salinomycin on ruminal fermentation, gas production, dry, organic matter and fiber degradation. Four experimental treatments were used by in-vitro batch culture technique, as follow: 60% CFM, 40% clover hay (control), control diet + 2.5 gm thyme + 2.5 gm celery kg-1 DM (T1), control diet + 5 gm thyme + 5 gm celery kg-1 DM (T2), control diet + 10 gm thyme + 10 gm celery kg-1 DM (T3), control diet + 0.4 gm Salinomycin kg-1 DM (T4). Ruminal pH value was significantly increased (p < 0.05) with T4 compared with other treatments. While, the T4 recorded the lowest value (p < 0.05) for microbial protein, short chain fatty acids concentrations (SCFA), total gas production, dry matter and organic matter degradability (DMd and OMd) compared with other treatments. Fiber fraction degradability (NDFd and ADFd) appeared no significant variance (p > 0.05) between control and other treatments except for T1 that recorded the lowest value (p < 0.05). It is concluded that mixture of thyme plus celery could be alternate for ionophores in the ruminant diets to enhance ruminal fermentation, reducing gas production without any negative effect on nutrients degradability.(AU)

Immunocastration on performance and meat quality of Bos indicus (Nellore) cattle under different nutritional systems

The present study aimed to evaluate the effects of immunocastration on the animal growth, carcass traits, and meat quality of Nellore cattle receiving or not Ionophore supplementation at pasture or pasture with concentrate (semi-feedlot). The first experiment (Pasture) was carried out during the rainy season, while the second (supplemented = Semi-feedlot) was conducted during the dry season. In each assessment, 60 males were allocated into three treatments, in a completely randomized design: non-castrated, immunocastrated (anti-gonadotropin-releasing hormone vaccine), and immunocastrated animals receiving ionophore. The highly energetic supplemented diet was prepared using 85 % corn and 10 % soybean meal at 1 % body weight, while the ionophore was provided with salt containing 1,650 mg kg−1 of lasalocid. After slaughter, the carcasses were graded, and Longissimus thoracis et lumborum samples were collected for meat quality analysis. The non-castrated animals exhibited a more significant final body weight and hot carcass weight than those immunocastrated regardless of ionophore supplementation (p < 0.05). The carcasses of non-castrated animals had less fat cover and marbling than castrated animals. A high incidence of dark cutting beef was verified in non-castrated animals. The immunocastrated cattle produced tenderer beef, mainly at pasture rearing. In conclusion, regardless of production system or ionophore supplementation, immunocastration was an adequate choice to generate high-quality meat, since it increased marbling and improved beef tenderness. However, limitations regarding animal growth should be estimated.(AU)

Intoxicação por lasalocida em bezerros búfalos no Estado do Pará, Brasil / Lasalocid poisoning in buffalo calves in the state of Pará, Brazil

Background: Ionophore antibiotics are food additives with coccidiostatic or antimicrobial action; they are also used as growth promoters, ruminal pH regulators, volatile fatty acid molar modifiers, and methanogenesis reducers. However, these compounds have the potential to cause microbial resistance, in addition to the risk of intoxication. Ionophore poisoning may be caused by excessive intake, sensitivity of certain animal species, and concomitant use with other drugs. In Brazil, cases of ionophore poisoning in buffalos are rare. This study aims to describe the epidemiological, clinical, and pathological findings of lasalocid poisoning in buffalo calves. Case: A visit was made to a farm in the municipality of Mojú, Pará state to care for Murrah buffalo calves. After weaning, the buffalos were grazed in paddocks with Panicum spp., and received a supplement of mineral, protein, and vitamin. This supplement contained, per kg, 250 g PB, 50 g Ca, 20 g P, 8 g S, 39 g Na, 20 mg Co, 557 mg Cu, 200 mg Fe, 12.4 mg Se, 2040 mg Zn, 0.19 mg biotin, 26750 IU of vitamin A, 4175 IU of vitamin D, 155 IU of vitamin E and 300 mg/kg of lasalocid. The product was made available to all calves, at 1-2 g/kg body weight (BW), according to the manufacturer's recommendations. Older calves were raised together with those less than 30 days old; as a result, the older calves tended to eat more, which could lead to a supplementation consumption of more than 1 kg body weight per animal per day. It was reported that between 40 and 60 days after the introduction of this supplement, 16 calves fell ill and died due to apathy, motor instability, tremors, and distended neck. The herd had a mortality rate of 33.3%. Two calves underwent a necroscopic examination at the Pathology Section of the Veterinary Institute of the Federal University of Pará. Macroscopic examination revealed extensive pale areas in the skeletal muscles, myocardium, and tongue. Fragments of these muscles and various organs were collected, fixed in 10% buffered formalin, processed according to the routine histological technique, and stained with hematoxylin-eosin and Masson's trichrome stain. Microscopic examination of the histologic samples revealed foci of muscle atrophy and necrosis characterized by an increase in cytoplasmic eosinophilia associated with the loss of stretch marks, and hyperchromatic nuclei that were displaced to the periphery. The necrosis of the muscle fibers was highlighted by Masson's trichrome staining. Discussion: The diagnosis of lasalocid poisoning in buffalo calves was based on epidemiological data, clinical findings, results of macroscopic and histopathological examination, and based on the estimated ionophore intake, obtained directly from the supplement label and by the calf's handler. Based on the absence of stratification of the calves by similarity of age and because the buffalo calves older than 30 days could eat more than 1 kg of the supplement (containing 300 mg/kg of lasalocid), it was possible to estimate the intake of lasalocid per kg CP (body weight). Therefore, the intake of lasalocid by a 70-kg buffalo calf in approximately 90 days and daily supplement consumption between 1 and 1.5 kg would be between 4.2 and 6.4 mg/kg of body weight. This report reinforces that notion that buffalo calves should never ingest ionophores; however, if necessary, strict protocols must be followed to avoid poisoning in these animals. This study highlighted the fact that stratification of buffaloes by different age groups during feeding became a risk factor that allowed greater consumption by older animals; this led to the estimated consumption of 4.2-6.4 mg/kg of lasalocid.

Salinomycin intoxication in pigs associated with the use of tiamulin in the State of Santa Catarina, Brazil / Intoxicação por salinomicina em suínos associado ao uso de tiamulina no Estado de Santa Catarina

This paper describes a spontaneous outbreak of toxic myopathy in finishing pigs due to the ingestion of feed with salinomycin associated with tiamulin and addresses the control methods performed during the outbreak to minimize economic losses resulting from the intoxication. A lot of 940 pigs fed feed containing 30 ppm salinomycin received 100 ppm tiamulin (via water) to control recurrent respiratory diseases on the farm. After ingesting tiamulin, some animals manifested clinical signs of motor incoordination, stiff gait, reluctance to move, muscle weakness and tremors, dyspnea, depression, and decubitus, remaining in "sitting-dog position" or with the abduction of the pelvic limbs, and rested on tip-toes when in a standing position. Two animals were euthanized for macro-and microscopic evaluation. The other sick animals received supportive anti-inflammatory treatment. The most relevant macroscopic finding observed during necropsy was the slight pallor of the pelvic limb muscles. The main histopathological findings consisted of multifocal areas of hyaline degeneration and marked necrosis of skeletal myofibers, with macrophage infiltrate associated with cell regeneration and skeletal fiber phagocytosis. These lesions were more intense in the longissimus dorsi, diaphragm, and masseter muscles. The definitive diagnosis was based on epidemiological aspects and clinical lesional conditions compatible with toxic myopathy secondary to ionophore intoxication.(AU)

Este trabalho descreve um surto espontâneo de miopatia tóxica em suínos na fase de terminação, decorrente da ingestão de ração contendo salinomicina associada a tiamulina e aborda os métodos de controle realizados durante o surto, para minimizar os prejuízos econômicos decorrentes da intoxicação. Um lote de 940 suínos alimentados com ração contendo 30 ppm de salinomicina recebeu tiamulina na dose de 100 ppm (via água) para controle de doenças respiratórias recorrentes na granja. Após a ingestão da tiamulina, alguns animais manifestaram sinais clínicos de incoordenação motora, andar rígido, relutância ao movimento, fraqueza e tremores musculares, dispneia, depressão e decúbito, permanecendo em "posição de cão sentado" ou com abdução dos membros pélvicos, e quando em estação, apoiavam-se nas pinças dos cascos. Dois animais foram eutanasiados para avaliação macro e microscópica. Os demais animais doentes receberam tratamento suporte com anti-inflamatório. O achado macroscópico mais relevante observado durante a necropsia foi palidez leve dos músculos dos membros pélvicos. Os principais achados histopatológicos foram áreas multifocais de degeneração hialina e necrose acentuada de miofibras esqueléticas, com infiltrado de macrófagos associado às figuras de regeneração celular e à fagocitose de fibras esqueléticas. Essas lesões foram mais intensas nos músculos longissimus dorsi, diafragma e masseter. O diagnóstico definitivo baseou-se nos aspectos epidemiológicos e no quadro clínico-lesional compatíveis com miopatia tóxica secundária a intoxicação por ionóforo.(AU)

Effect of mixture of herbal plants on ruminal fermentation, degradability and gas production

Reducing livestock negative environmental impacts get great interest in last years. So, present study was carried out to determine the effect of adding different levels of mixture of thyme and celery versus salinomycin on ruminal fermentation, gas production, dry, organic matter and fiber degradation. Four experimental treatments were used by in-vitro batch culture technique, as follow: 60% CFM, 40% clover hay (control), control diet + 2.5 gm thyme + 2.5 gm celery kg-1 DM (T1), control diet + 5 gm thyme + 5 gm celery kg-1 DM (T2), control diet + 10 gm thyme + 10 gm celery kg-1 DM (T3), control diet + 0.4 gm Salinomycin kg-1 DM (T4). Ruminal pH value was significantly increased (p 0.05) between control and other treatments except for T1 that recorded the lowest value (p < 0.05). It is concluded that mixture of thyme plus celery could be alternate for ionophores in the ruminant diets to enhance ruminal fermentation, reducing gas production without any negative effect on nutrients degradability.

Immunocastration on performance and meat quality of Bos indicus (Nellore) cattle under different nutritional systems

The present study aimed to evaluate the effects of immunocastration on the animal growth, carcass traits, and meat quality of Nellore cattle receiving or not Ionophore supplementation at pasture or pasture with concentrate (semi-feedlot). The first experiment (Pasture) was carried out during the rainy season, while the second (supplemented = Semi-feedlot) was conducted during the dry season. In each assessment, 60 males were allocated into three treatments, in a completely randomized design: non-castrated, immunocastrated (anti-gonadotropin-releasing hormone vaccine), and immunocastrated animals receiving ionophore. The highly energetic supplemented diet was prepared using 85 % corn and 10 % soybean meal at 1 % body weight, while the ionophore was provided with salt containing 1,650 mg kg−1 of lasalocid. After slaughter, the carcasses were graded, and Longissimus thoracis et lumborum samples were collected for meat quality analysis. The non-castrated animals exhibited a more significant final body weight and hot carcass weight than those immunocastrated regardless of ionophore supplementation (p < 0.05). The carcasses of non-castrated animals had less fat cover and marbling than castrated animals. A high incidence of dark cutting beef was verified in non-castrated animals. The immunocastrated cattle produced tenderer beef, mainly at pasture rearing. In conclusion, regardless of production system or ionophore supplementation, immunocastration was an adequate choice to generate high-quality meat, since it increased marbling and improved beef tenderness. However, limitations regarding animal growth should be estimated.

Polyether ionophores residues in Minas Frescal cheese by UHPLC-MS/MS.

An analytical method was developed and validated for the determination of three polyether ionophores (monensin, lasalocid, and salinomycin) in 60 samples of Brazilian Minas Frescal cheese by UHPLC-MS/MS. Linearity ranged from 1 to 8 µg kg-1 for monensin and salinomycin, and from 0.50 to 4 µg kg-1 for lasalocid. Limits of detection and quantitation were 0.50 µg kg-1 and 1 µg kg-1, respectively, for both monensin and salinomycin, and 0.25 µg kg-1 and 0.50 µg kg-1, respectively, for lasalocid. Recoveries were between 69% and 84% with coefficients of variation up to 16.28% for repeatability and 13.79% for intermediate precision. A total of 60 samples of Minas Frescal cheese were analysed and only monensin residues were found. Monensin was detected in 55% of the samples and quantified in 5 of them at mean levels varying from 1.00 to 1.73 µg kg-1. The proposed method demonstrated the suitability for monitoring these substances in cheese.

Virginiamycin and sodium monensin supplementation for beef cattle on pasture / Suplementação com virginiamicina e monensina sódica para bovinos de corte a pasto

The aim of this paper was to evaluate the effects of including virginiamycin (VM), sodium monensin (MON) or the association (VM+MON) in the energetic mineral supplement, on the intake and performance of beef cattle on pasture. Forty Nellore heifers with 24 months of age and initial body weight (BW) of 251.5±16.6kg, were distributed in four treatments in a randomized block design. Treatments consisted of adding VM, MON or VM+MON to the supplement (CONT). Additive concentrations were defined to reach a dose of 40 to 45mg/100kg BW. The herbage allowance was not a limiting factor for the animals' intake. Supplement intake was lower than expected, with 33.0, 18.8 and 26.3mg per 100kg BW for VM, MON and VM+MON, respectively. Dry matter intake (DMI, mean=2.65% BW) and animal performance were not affected by the inclusion of additives. The average daily gain (ADG) was 0.561kg/animal day-1. The inclusion of additives in energetic mineral supplement does not affect the DMI and the ADG of grazing animals. The variability in supplement intake and daily dose intake of additives may have influenced the performance of the animals. Monensin inclusion presented the less expensive supplementation cost, due to reduction in supplement intake without changing weight gain.(AU)

Objetivou-se avaliar o efeito da inclusão dos aditivos virginiamicina (VM), monensina sódica (MON) e associação (VM+MON) no suplemento energético-mineral sobre o consumo e desempenho de bovinos manejados em pastagem de Urochloa Brizantha cv. Marandu. Foram utilizadas 40 novilhas Nelore com 24 meses de idade e peso corporal (PC) inicial médio de 251,5+16,6kg distribuídas em delineamento em blocos ao acaso com quatro tratamentos. Os tratamentos consistiam de suplemento energético-mineral (CONT) acrescido de VM, MON ou VM+MON. A oferta de forragem não limitou o consumo dos animais. O consumo dos aditivos foi de 0; 33,0; 18,8 e 26,3mg por 100kg de PC para CONT, VM, MON e VM+MON, respectivamente. O consumo de matéria seca e o desempenho dos animais não foram afetados pela inclusão dos aditivos. O ganho médio diário dos animais foi de 0,561kg dia -1 , sem diferença entre os tratamentos. A inclusão de aditivos no suplemento energético-mineral não alterou o CMS e o desempenho dos animais em pastejo. A variabilidade no consumo de suplemento e na dose ingerida dos aditivos pode ter influenciado o desempenho dos animais.(AU)

Virginiamycin and sodium monensin supplementation for beef cattle on pasture / Suplementação com virginiamicina e monensina sódica para bovinos de corte a pasto

The aim of this paper was to evaluate the effects of including virginiamycin (VM), sodium monensin (MON) or the association (VM+MON) in the energetic mineral supplement, on the intake and performance of beef cattle on pasture. Forty Nellore heifers with 24 months of age and initial body weight (BW) of 251.5±16.6kg, were distributed in four treatments in a randomized block design. Treatments consisted of adding VM, MON or VM+MON to the supplement (CONT). Additive concentrations were defined to reach a dose of 40 to 45mg/100kg BW. The herbage allowance was not a limiting factor for the animals' intake. Supplement intake was lower than expected, with 33.0, 18.8 and 26.3mg per 100kg BW for VM, MON and VM+MON, respectively. Dry matter intake (DMI, mean=2.65% BW) and animal performance were not affected by the inclusion of additives. The average daily gain (ADG) was 0.561kg/animal day-1. The inclusion of additives in energetic mineral supplement does not affect the DMI and the ADG of grazing animals. The variability in supplement intake and daily dose intake of additives may have influenced the performance of the animals. Monensin inclusion presented the less expensive supplementation cost, due to reduction in supplement intake without changing weight gain.(AU)

Objetivou-se avaliar o efeito da inclusão dos aditivos virginiamicina (VM), monensina sódica (MON) e associação (VM+MON) no suplemento energético-mineral sobre o consumo e desempenho de bovinos manejados em pastagem de Urochloa Brizantha cv. Marandu. Foram utilizadas 40 novilhas Nelore com 24 meses de idade e peso corporal (PC) inicial médio de 251,5+16,6kg distribuídas em delineamento em blocos ao acaso com quatro tratamentos. Os tratamentos consistiam de suplemento energético-mineral (CONT) acrescido de VM, MON ou VM+MON. A oferta de forragem não limitou o consumo dos animais. O consumo dos aditivos foi de 0; 33,0; 18,8 e 26,3mg por 100kg de PC para CONT, VM, MON e VM+MON, respectivamente. O consumo de matéria seca e o desempenho dos animais não foram afetados pela inclusão dos aditivos. O ganho médio diário dos animais foi de 0,561kg dia -1 , sem diferença entre os tratamentos. A inclusão de aditivos no suplemento energético-mineral não alterou o CMS e o desempenho dos animais em pastejo. A variabilidade no consumo de suplemento e na dose ingerida dos aditivos pode ter influenciado o desempenho dos animais.(AU)

Effects of essential oils of Cashew and Castor on intake, digestibility, ruminal fermentation and purine derivatives in beef cattle fed high grain diets / Efeito de óleos essenciais de Caju e Mamona sobre a ingestão, digestibilidade, fermentação ruminal e derivados de purina em bovinos de corte alimentados com dietas alto grão

The objective of this study was to determine the effects of essential oils of Anacardium occidentale (Cashew) and Ricinus communis (Castor) on intake, digestibility, ruminal fermentation and excretion of purine derivatives in beef cattle fed high grain diets. Five Nellore steers fitted with ruminal cannula were used in a 5x5 Latin square design (21 days period). The treatments were control MON (0.2 g monensin animal day-1) and 1, 2, 4 and 8 g EO animal day-1 (Essential oils - Oligobasics®). All the animals had a basal diet, corn silage-based total mixed ration (TMR) of 80:20 concentrate:forage ratio. Intake, digestibility, ruminal fermentation and excretion of purine derivatives were determined over five consecutive days in each period. Intake and digestibility of dry matter (DM), neutral detergent fibre (NDF) and crude protein (CP) were not influenced by treatments (P > 0.05). However, increasing levels of EO showed a quadratic effect (P < 0.014) above 2 g animal day-1 on the ruminal pH. The excretion of allantoin and uric acid were not influenced by the treatments (P > 0.05), but levels above 2 g day decreased the synthesis of microbial proteins (P < 0.05). It is concluded that the EO of A. occidentale and R. comunnis effectively controlled ruminal fermentation as well as sodium monensin at the studied levels. EOs have the potential to be used in place of monensin in the studied levels.(AU)

O objetivo deste estudo foi determinar o efeito dos óleos essenciais de Anacardium occidentale (Caju) e Ricinus communis (Mamona) sobre a ingestão, digestibilidade, fermentação ruminal e excreção de derivados de purina em bovinos de corte alimentados com dietas alto grão. Cinco novilhos da raça Nelore, com cânula ruminal, foram utilizado um delineamento quadrado latino 5x5 (período de 21 dias). Os tratamentos foram controle MON (0,2 g monensina animal dia-1) e 1, 2, 4 e 8 g OE animal dia-1 (óleos essenciais - Oligobasics®). Todos os animais foram alimentados com uma dieta basal 20:80 volumoso: concentrado. Ingestão, digestibilidade, fermentação ruminal e excreção de derivados de purina foram determinados ao longo de cinco dias consecutivos em cada período. A ingestão e a digestibilidade da matéria seca (MS), fibra em detergente neutro (FDN) e proteína bruta (PB) não foram influenciadas pelos tratamentos (P > 0,05). No entanto, níveis crescentes de OE apresentaram efeito quadrático (P < 0,014) acima de 2 g animal dia-1 no pH ruminal. A excreção de alantoína e ácido úrico não foi influenciada pelos tratamentos (P > 0,05), mas níveis acima de 2 g dia-1 diminuíram a síntese de proteínas microbianas (P < 0,05). Conclui-se que o OE de A. occidentale e R. comunnis controlam efetivamente a fermentação ruminal, assim como a monensina sódica, nos níveis estudados, podendo substituir a monensina nos níveis estudados.(AU)