Draft genome sequence of Mannheimia haemolytica strain Oliden, isolated from a calf lung infection in Argentina.

We present the draft genome sequence of a Mannheimia haemolytica strain isolated from a postmortem lung lesion from a calf diagnosed with bovine respiratory disease. The genome sequence was 2,749,707-bp long with 2,909 putative protein-encoding genes.

Bovine respiratory syncytial virus infection in feedlot cattle cases in Argentina.

Although bovine respiratory syncytial virus (BRSV) infection has been reported in cattle in Argentina, it has not been associated with pneumonia in Argentina. We report here 5 cases of bovine pneumonia associated with BRSV. Autopsies were performed on 35 beef cattle with gross and/or microscopic lesions of pneumonia from 3 commercial feedlots. Lung samples in 5 of 35 animals were BRSV-positive by reverse-transcription nested PCR. The lungs of 2 of these 5 animals were coinfected with Mannheimia haemolytica, and 1 with bovine viral diarrhea virus 1. Microscopically, the lungs of 3 of the 5 BRSV PCR-positive animals had fibrinosuppurative bronchopneumonia, with or without pleuritis; 2 of the 5 had interstitial pneumonia. We conclude that BRSV is part of the bovine respiratory disease complex in Argentina.

Safety Study on Ketoprofen in Pigs: Evaluating the Effects of Different Dosing and Treatment Scheme on Hematological, Hepatic, and Renal Parameters.

A safety study on ketoprofen 10% was carried out on pigs using a different dosing and treatment scheme. Forty healthy crossbreed pigs with similar age, weight, and body condition score were distributed into five treatment groups. The pigs were intramuscularly injected once with different doses of ketoprofen: 3 mg/kg (group 1X), 6 mg/kg (group 2X), 9 mg/kg (group 3X). In addition, the 3 mg/kg dosis was administered on three consecutive days (group 1X ext.). Intramuscular injections of saline solution were used in control group (CTL). The pigs were clinically examined throughout the trial and blood samples were taken for hematological and biochemical evaluation on days -4 (before treatment), +3, +7, and +14 (the end of the trial). Any unusual behaviour or clinical signs were reported as potential toxic effects of ketoprofen. Serum measurements showed that none of the ketoprofen doses produced changes in renal or hepatic biochemical parameters, liver enzymes, or total bilirubin. Likewise, hematological assessment indicated no altered parameters or hematocrit percentage in the study groups. These results demonstrate that ketoprofen has no adverse effects in pigs when the doses and scheme evaluated in this study are applied.

Assessment of Plasma Zinc and Total Leukocyte Count in Calves Experimentally Infected with Mannheimia haemolytica.

Mannheimia haemolytica is the main bacterial pathogen isolated in bovine respiratory disease (BRD), a common disease affecting calves before weaning. Previous research has shown that experimental infection with bovine herpesvirus 1, a respiratory virus, decreases plasma zinc (Zn) levels. However, changes in plasma Zn concentrations in calves experimentally infected with M. haemolytica have not been studied thus far. The objective of this study was to evaluate the effect of experimental infection with M. haemolytica on plasma Zn concentration in calves. Total leukocyte count and bovine respiratory disease (BRD) clinical score were also evaluated. We conducted a 6-day trial in 14 male Holstein calves randomly assigned to one of two groups, experimental (EG, n = 8) and control (CG, n = 6). Animals in EG were intrabronchially inoculated with M. haemolytica (6.5 × 106 CFU/mL) on day 0 of the trial. Plasma Zn levels were affected by time, treatment, and time by treatment interaction, being lower in EG compared with CG on days 1, 2, and 3. Differences in total leukocyte count were significant on day 1, observing a tendency on day 3. BRD clinical score differed between groups, being higher in EG throughout the trial. We conclude that experimental M. haemolytica infection reduced plasma Zn concentration in clinically ill calves, suggesting that the clinical condition of animals (healthy/ill) should be considered to better interpret plasma Zn values.

Effects of Parenteral Supplementation with Minerals and Vitamins on Oxidative Stress and Humoral Immune Response of Weaning Calves.

We aimed to evaluate the effects of injectable mineral and vitamin supplementation on weaning calves subjected to a low-stress (fence-line) weaning system. Seven-month-old Aberdeen Angus female calves (n = 40, 152 ± 11 kg body weight) from a selenium-deficient area of extensive cattle production on natural grass were randomly assigned to two groups (n = 20 each). One group received subcutaneous supplementation with copper, zinc, selenium, manganese and vitamins A and E (SG), and the other was given sterile saline solution (CG). The animals were supplemented twice, seven days before weaning (day -7) and on the day of weaning (day 0), and they were evaluated 30 (+30) and 60 (+60) days after weaning. Total antioxidant status (TAS), selenium-dependent glutathione peroxidase (GPx) activity, body weight, and average daily gain (ADG) were evaluated. Additionally, antibody titers were assessed prior to and after each immunization with a vaccine containing bovine herpes virus type 1 (BoHV-1). On day +30, body weight (p = 0.03) was higher in SG, whereas TAS (p = 0.02) and GPx (p = 0.0038) activity were lower in CG and remained constant in SG. Antibody titers increased in SG and CG following immunization, being higher in SG on days +30 and +60 (p < 0.05). In conclusion, parenteral supplementation of minerals and vitamins with antioxidant effects in a low-stress weaning system prevented the decrease in TAS and GPx activity, improved antibody response and had positive effects on body weight.

Pharmacokinetic profile and anthelmintic efficacy of moxidectin administered by different doses and routes to feedlot calves.

We evaluated the comparative plasma disposition kinetics and efficacy of moxidectin (MXD), administered by the intraruminal (IR) or subcutaneous (SC) route at two different dosage levels (0.2 and 1 mg/kg) in feedlot calves. Additionally, the efficacy was compared to an ivermectin (IVM, SC administration) treated group. This study was divided into two separate studies, the "Pharmacokinetic (PK) study" and the "Efficacy study". The "PK study" involved 24 calves free of gastrointestinal nematodes (GIN), which were allocated into 4 groups (n = 6) and treated with MXD by either the SC or the IR route at the therapeutic (MXDSC0.2, MXDIR0.2, respectively) or at fivefold the therapeutic dose (MXDSC1.0, MXDIR1.0, respectively). Blood samples were collected from 3 h up to 14 days post-treatment. MXD concentrations in plasma samples were analyzed by HPLC. The "Efficacy study" included 125 calves naturally infected with GIN, which were allocated into five experimental groups (n = 25 each); the same four MXD-treated groups described for the "PK study", and an additional group treated by the SC route with IVM (IVMSC0.2). The efficacy of IVM given at its therapeutic dose and the different MXD groups at the therapeutic and fivefold the therapeutic dose was calculated by analysis of the individual efficacy using the package eggCounts-2.1-1' on the R software environment, version 3.5.0 (R Core Team, 2018). Daily weight gain (DWG) was also measured over the first 47 days of the fattening cycle. Independently of the administration route, MXD peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) were higher in groups treated with the higher dose (1.0 mg/kg), whereas a longer time to reach Cmax (Tmax) was observed after the IR treatments. The observed MXD efficacies were 85% (MXDSC0.2), 94% (MXDSC1.0), 84% (MXDIR0.2) and 99% (MXDIR1.0), at day +27. At day +27, all MXD-treated groups showed higher efficacies than the group having received IVM (45%). The post-treatment Cooperia spp. L3 counts were particularly low in the groups MXDSC1.0 and MXDIR1.0. All of the groups treated with MXD showed better DWG than the IVMSC0.2 group (P = 0.01). Dose and administration route modifications effectively improved the anthelmintic and productive performance of MXD. A high dose of MXD improved the control of IVM-resistant GIN in feedlot calves. However, this practice must be taken with caution, since MXD resistance could rapidly emerge, especially in grazing cattle.

Effect of Injectable Copper and Zinc Supplementation on Weight, Hematological Parameters, and Immune Response in Pre-weaning Beef Calves.

Copper (Cu) and zinc (Zn) deficiency may cause poor weight gain, hematological changes, and immune failure in extensive beef cattle breeding systems. Diagnosis of the deficiency is based on plasma Cu and Zn concentrations; however, there are discrepancies regarding data interpretation. Here, plasma Cu and Zn concentrations are discussed as risk markers. We evaluated the effect of parenteral Cu and Zn supplementation on their plasma concentrations, weight gain, hematological parameters, and antibody titers to bovine herpes virus 1 (BoHV-1). Pre-weaning calves (n = 40; 99 ± 8 kg bw) from a typical breeding area of Argentina with background Cu and Zn deficiency were used. They were assigned to two homogeneous groups in a completely randomized design. Calves were subcutaneously injected with 0.3 mg/kg Cu and 1 mg/kg Zn (supplemented group), or saline solution (control), every 40 days during 120 days. Plasma Cu and Zn concentrations, hematological parameters, and weight were recorded. On days 40 and 80 of the trial, calves were vaccinated with inactivated BoHV-1. Antibody immune response was measured on days 80 and 120. Data were analyzed with a mixed model for repeated measures over time. Before treatment, plasma Cu was low and Zn was adequate in both groups. After treatment, plasma Cu increased and remained within a normal range, whereas plasma Zn remained constant. Supplemented animals had higher weight gain (p < 0.01); higher hematocrit, mean corpuscular volume, and mean corpuscular hemoglobin levels (p < 0.05); and higher immune response to BoHV-1 (p < 0.05). Our results suggest that Cu and Zn supplementation improved daily weight gain and the immune response of pre-weaning calves.

Effects of Copper and Zinc Supplementation on Weight Gain and Hematological Parameters in Pre-weaning Calves.

Cow-calf operations may be affected by trace mineral deficiencies, particularly copper (Cu) and zinc (Zn) deficiency, which may decrease the calf daily weight gain and alter hematological parameters. We evaluated the effect of Cu and Zn supplementation on pre-weaning calves (n = 40; 92 ± 6 kg initial body weight) from the Salado River basin, Buenos Aires, Argentina. Calves were divided into four groups (n = 10 each) and subcutaneously administered 0.3 mg/kg Cu (Cu group), 1 mg/kg Zn (Zn group), Cu and Zn together (Cu + Zn group), and sterile saline solution (control group) every 40 days for 120 days. Plasma Cu and Zn concentrations, hematological parameters, and weight were recorded every 40 days. A completely randomized 2 × 2 factorial treatment design was used and data were analyzed with a mixed model for repeated measures over time. Cu and Zn were detected in plasma after the second sampling. Cu × Zn interaction was significant (p = 0.09), being Cu concentration higher in the Cu + Zn than in the Cu group. Differences in weight gain (Zn × time interaction; p < 0.01) were observed in the Zn but not in the Cu group (p > 0.1). On the other hand, none of the treatments altered any of the hematological parameters assessed (p > 0.1). Our results show the risk of lower weight gain due to Zn deficiency in pre-weaning calves raised in the Salado River basin.

Assessment of Cu-Zn EDTA Parenteral Toxicity in Calves.

Copper (Cu) parenteral administration is used in a beef cow-calf operations to prevent or correct Cu deficiency in bovines. At present, Zinc (Zn) salts have been incorporated to complement Cu antioxidant effect. A risk of hepatotoxicity generated by overdose is a negative consequence of injectable Cu application. Cu-Zn EDTA appears as an alternative; however, data about its toxicity is unknown. The aim of this study was to assess toxicity risk of different doses of Cu-Zn EDTA in calves. Thirty two Aberdeen Angus calves of 162 (±20) kg BW were assigned to 4 groups (n = 8), homogeneous in weight, sex, and age. Cu-Zn EDTA was administrated in doses of 0.3 mg/kg BW (group 1X); 0.6 mg/kg BW (group 2X); 0.9 mg/kg BW (group 3X) and sterile saline solution (control group-with no treatment). Clinical and blood parameters in animals were monitored during 28 days. In groups' control, 1X and 2X there were no alterations in the assessed parameters. In group 3X, one of the animals showed depression, permanent decubitus, and muscular twitching; that animal had to be killed in extremis for humanitarian reasons. Necropsy and Cu tissue concentration findings confirmed intoxication in the clinically affected animal. The rest of the animals in group 3X showed only a temporary increase in liver enzymes. The results indicate that a dose of 0.9 mg/kg BW of Cu as Cu-Zn EDTA is potentially hepatotoxic, this dose is similar to other soluble salts of parenteral administration.

Impact of ivermectin-resistant gastrointestinal nematodes in feedlot cattle in Argentina / Impacto de nematódeos gastrointestinais ivermectina-resistentes em bovinos em confinamento na Argentina

The aim was to evaluate for 75 days the impact on production of the remaining burden of ivermectin (IVM)-resistant parasites in naturally infected feedlot calves. The herds came from tick-infested areas of cattle breeding where the systematic use of IVM to control tick increases the gastrointestinal parasites resistant to this drug. This investigation was carried out in two commercial feedlots in Buenos Aires province. In feedlot A, two groups of 35 animal each received IVM 1% and the other received ricobendazole (RBZ) 10% respectively. The same was done in feedlot B. On day 0, two groups of 35 animals were made in feedlots A and B. Fecal samples were taken on days 0, 22, 54 and 75 pos-treatment (PT), and body weight was registered, from each animal. Fecal samples were processed for individual count of eggs per gram (EPG) and pooled fecal culture was carried out for identification of the parasite genus in each sampling. Fecal egg count reduction test (FECR) was calculated on day 22 PT. The study design used was a totally randomized block, with commercial feedlot and sex as block variables. For data analysis, a mixed model of the SAS statistical program was used. The FECR average on day 22 was 28.4% in the IVM group, and 94,2 % in the RBZ group . From this date on, significant differences in EPG were kept until day 54. EPG counts were only equal near the end of the trial, on day 75 (p=0.16). In both commercial feedlots, especially in the IVM group, Cooperia spp. was the most prevalent parasite in the fecal cultures. Significant differences in weight (P<0.01) on post-treatment day 75 was found between the average weight in the RBZ and the IVM group (246 vs. 238 kg respectively), what means a difference of 8.3% in gains. The importance for production in the antiparasite failure treatment in commercial feedlots was demonstrated, and the need of pos-treatment controls to evaluate the efficacy of the antiparasitic administered is emphasized.

O objetivo deste trabalho foi avaliar durante 75 dias o impacto sobre a produção da carga de parasita-ivermectina (IVM) resistentes remanescentes em bezerros naturalmente infectados no confinamento. Os rebanhos são provenientes de áreas infestadas por carrapatos, onde o uso sistemático de IVM para o controle do carrapato aumenta a resistência de parasita gastrintestinais a esta droga. Este trabalho foi realizado em dois confinamentos comerciais na província de Buenos Aires. Na fazenda A, dois grupos de 35 animais cada receberam IVM 1% e ricobendazole (RBZ) 10%, respectivamente. O mesmo foi feito no confinamento B. No dia 0, dois grupos de 35 animais foram feitos nas fazendas A e B. As amostras fecais foram tomadas nos dias 0, 22, 54 e 75 pós-tratamento (PT) e o peso corporal foi registrado, de cada animal. Amostras fecais foram processadas para a contagem individual de ovos por grama (EPG). Amostras fecais foram agrupadas para a identificação do gênero parasitária. O teste de redução de ovos fecais (TROF) foi calculado no dia 22 PT. O desenho do estudo utilizado foi aquele dos blocos inteiramente randomizados, sendo confinamento comercial e sexo as variáveis de bloco. Para a análise dos dados, um modelo misto do programa estatístico SAS foi utilizado. A média TROF no dia 22 foi de 28,4% no grupo IVM e 94,2% no grupo RBZ. A partir desta data, diferenças significativas na EPG foram mantidas até o dia 54. Contas de OPG só foram iguais perto do fim do estudo, no dia 75 (p=0,16). Em ambos os confinamentos comerciais, especialmente no grupo IVM, Cooperia spp. foram os parasitos mais prevalentes nas culturas fecais. Diferenças significativas no peso (P<0,01) 75 dias pós-tratamento foram encontradas entre o peso médio nos grupos RBZ e IVM (246 vs 238 kg, respectivamente), o que significa uma diferença de 8,3% nos ganhos. A importância para a produção no tratamento da insuficiência antiparasitários em confinamento comercial foi demonstrada, bem como a necessidade de controles pós-tratamento para avaliar a eficácia dos antiparasitários administrados é enfatizada.

Renal cortex copper concentration in acute copper poisoning in calves / Concentração de cobre no córtex renal na intoxicação aguda de cobre em bezerros

The aim of this study was to estimate the diagnostic value of renal cortex copper (Cu) concentration in clinical cases of acute copper poisoning (ACP). A total of 97 calves that died due to subcutaneous copper administration were compiled in eleven farms. At least, one necropsy was conducted on each farm and samples for complementary analysis were taken. The degree of autolysis in each necropsy was evaluated. The cases appeared on extensive grazing calf breeding and intensive feedlot farms, in calves of 60 to 200 kg body weight. Mortality varied from 0.86 to 6.96 percent, on the farms studied. The first succumbed calf was found on the farms between 6 and 72 hours after the susbcutaneous Cu administration. As discrepancies regarding the reference value arose, the local value (19.9 parts per million) was used, confirming the diagnosis of acute copper poisoning in 93 percent of the analyzed kidney samples. These results confirm the value of analysis of the cortical kidney Cu concentration for the diagnosis of acute copper poisoning.

O objetivo deste trabalho foi estimar o valor diagnóstico de concentração de cobre (Cu) no córtex do rim em casos clínicos da intoxicação cobre aguda (ACP). Um total de 97 bezerros foi compilado em onze fazendas. Pelo menos, uma necropsia foi realizada em cada caso e foram colhidas amostras para análise complementar. O grau de autólise em cada necropsia foi avaliado. Os casos aparecem em criação extensiva e também em fazendas de confinamento intensivo. Os pesos dos animais variavam de 60 até 200 kg. Mortalidade variou entre 0,86 e 6,96 por cento, em todas as fazendas estudadas, o primeiro animal morto foi observado entre 6 e 72 horas após à administração parenteral de Cu. Surgirem discrepâncias em relação ao valor de referência a ser usado. O valor local (19. 9 partes por milhão) foi usado, confirmando o diagnóstico de intoxicação aguda de cobre em 93 por cento das amostras analisadas nos rins. Estes resultados confirmam o valor diagnóstico da concentração de Cu no rim córtex para o diagnóstico de ACP.

Diagnostic value of copper parameters to predict growth of suckling calves grazing native range in Argentina / Valor diagnóstico dos parâmetros de cobre para prever o crescimento de bezerros lactantes em pastagem nativas na Argentina

A study was conducted to evaluate the predictive diagnostic value of different copper (Cu) parameters as indicators of average daily gain (ADG) in growing calves. The effects in calves of cow Cu supplementation in the last one-third gestation period were also evaluated. Five supplementation trials, with a total of 300 calves, were carried out. Two groups of 30 calves were randomly assigned to each trial, one group was parenterally supplemented (SG) and the other was not supplemented (NSG). Trials began when calves were three-month-old and ended at weaning time. At each sampling calves were weighed and blood was taken to determine Cu concentrations in plasma, Whole Blood (WB), Red Cells (RC) and Packed Cell Volume (PCV). Liver samples from six animals of each group were taken both at the beginning and at the end of the trial. In two trials the mothers of the SG received Cu supplementation at the last one- third gestation period. Four of the five trials exhibited low ADG in the NSGs. In these groups, plasma Cu concentration decreased rapidly before low ADG was detected, which occurred with values remaining below 25µg/dl. The decrease of RC Cu concentration was considerably slow. WB showed an intermediate position. PCV in the SGs was higher than in the NSGs in all trials. Cow supplementation was insufficient to generate a liver storage able to last after calves reached the 3 months of age. These data could be useful to predict the risk of low ADG in grazing calves.

Foi realizado um estudo para predisser o valor diagnóstico de diferentes parâmetros de cobre (Cu) como indicadores de ganho médio diário (ADG) na criação de bezerros. Também foram avaliados os efeitos da suplementação com Cu nas vacas no último terço da gestação. Cinco ensaios de suplementação, com um total de 300 bezerros, foram realizados. Dois grupos de 30 bezerros foram atribuídos aleatoriamente em cada proba, um grupo foi parenteralmente suple mentado (SG) e o outro não foi suplementado (NSG). Os ensaios começaram quando os bezerros tinham três meses de idade e terminou ao tempo do destete. Em cada ensaio os bezerros foram pesados e mostras do sangue foi tomada para determinar as concentrações Cu no plasma, sangue total (WB), eritrócitos (RC) e hematócrito (PCV). Amostras de fígado foram colhidas em seis animais de cada grupo tanto no início quanto no final do ensaio As mães do SG receberam suplementação de Cu no último terço da gestação em dois ensaios. Quatro dos cinco ensaios apresentavam baixa ADG nos NSGs. Nesses grupos, a concentração plasmática de Cu diminuiu rapidamente antes que a baixa do ADG fossei detectada, o que ocorreu com os valores abaixo 25 µg/d. A diminuição da concentração de RC Cu foi bastante lenta. WB mostrou uma posição intermédia. PCV nos SGs foi mais elevado do que nos NSGs em todos os ensaios. A suplementação das vacas foi insuficiente para gerar um armazenamento hepático capaz de durar até os 3 meses de idade dos bezerros. Estes dados poderiam ser úteis para prever o risco de baixa ADG em bezerros em pastagem.