Liver function markers and haematological dynamics during acute and chronic phases of experimental Fasciola

Fasciola hepatica, a worldwide-distributed liver fluke, is one of the causative agents of fasciolosis, a zoonotic disease that affects livestock and humans. In livestock, fasciolosis causes huge economic losses worldwide, reducing animal fertility, milk production, weight gain and condemnation of livers. In spite of the availability of drugs, such as triclabendazole (TCZ), for the treatment of fasciolosis, they do not necessarily prevent liver damage or parasite reinfection and can eventually increase parasite resistance. The aim of this research was to relate the hepatic function, haematological parameters, leukocyte counts in circulation and parasite egg shedding during F. hepatica acute and chronic phases of infection in cattle as well as to determine how these parameters change with TCZ-treatment of chronically infected cattle. Our results show that increased levels of serum aspartate aminotransferase (AST) and gamma glutamyltransferase (GGT) were detected in early stages of the experimental infection. Moreover, high circulating eosinophil count and plateletcrit levels were correlated with fluke number in livers from infected cattle. On the other hand, although TCZ-treatment in the chronic phase of infection reduced parasite burden and damage in the liver, it was not able to completely avoid them. In conclusion, our work sheds light into the physiopathological mechanisms induced during fluke infection in cattle, revealing the complexity of the host response to the infection, together with the effects of TCZ-treatment in chronically infected animals.Agencia Nacional de Investigación e InnovaciónInstituto Nacional de Investigación Agropecuari

Providing heat-stress abatement to late-lactation Holstein cows affects hormones, metabolite blood profiles, and hepatic gene expression but not productive responses

Objective: Our objective was to evaluate the effects of providing shade and shade combined with evaporative cooling on production, cow activity, metabolism, and hepatic gene expression of late-lactation Holstein dairy cows under moderate heat-stress conditions. Materials and Methods: Forty-eight multiparous Holstein cows were used in a completely randomized block-design trial and randomly assigned to 1 of 3 treatments: control (CTL), without access to shade; access to artificial shade (SH); and shade combined with evaporative cooling (SHplus). Results were analyzed using a mixed procedure with repeated measures. Results and Discussion: No differences were observed in DMI. Milk yield was not different among treatments, but lactose concentration was greater in SHplus. Treatments CTL and SH had greater BW losses than SHplus. Control cows spent less time grazing. The CTL and SH had higher p.m. rectal temperatures than SHplus, whereas CTL had the highest p.m. respiration rate. Control cows had greater serum insulin levels. Control and SH had greater BHB and urea concentrations and lower glucose concentration compared with SHplus. The hepatic expression of PCK1, PDK4, and HP genes was downregulated in SH and SHplus relative to control. Hepatic expression of NFKB1 was downregulated, whereas SOCS2 was upregulated, for SHplus compared with CTL. Implications and Applications: Despite the absence of treatment effects on productive variables, changes in blood profiles and hepatic expression of target genes were observed among treatments. These results suggest that the provision of shade combined with evaporative cooling was effective in alleviating the negative effects of heat stress.Fil: Martínez, Rocío Soledad. Instituto Nacional de Investigacion Agropecuaria;Fil: Palladino, Rafael Alejandro. Universidad Nacional de Lomas de Zamora; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Unidad Ejecutora de Investigaciones en Producción Animal. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Unidad Ejecutora de Investigaciones en Producción Animal; ArgentinaFil: Banchero, Georgget. Instituto Nacional de Investigacion Agropecuaria;Fil: Fernández y Martín, Rafael. Universidad de Buenos Aires. Facultad de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Unidad Ejecutora de Investigaciones en Producción Animal. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Unidad Ejecutora de Investigaciones en Producción Animal; ArgentinaFil: Nanni, Mariana Sandra. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Agroindustria. Instituto de Tecnología de los Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Juliano, Nicolas. Universidad de Buenos Aires. Facultad de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Iorio, Jesica Daniela. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: La Manna, Alejandro. Instituto Nacional de Investigacion Agropecuaria

Mycobacterium paratuberculosis sheep type strain in Uruguay: evidence for a wider geographic distribution in South America

Johne's disease (JD) is an economically important disease of ruminants caused by Mycobacterium avium paratuberculosis (MAP), which also infects other species including humans. Two major MAP strain types are currently recognized: sheep (S) and cattle (C) types. Information on JD prevalence and MAP types infecting small ruminants in South America is limited, and all but one of the MAP types reported from this region are of the C type. This study describes clinicopathological, molecular and microbiological findings in 11 cases of JD caused by a type S MAP strain, and estimated true within-flock prevalence in a ~735-sheep operation in Uruguay. Postmortem examination and histology (hematoxylin-eosin and Ziehl-Neelsen stains) of samples from 41 selected sheep revealed lymphohistiocytic/granulomatous enteritis and mesenteric lymphadenitis in 11 animals, with moderate/severe multibacillary lesions in 6 clinical cases, and minimal/mild paucibacillary lesions in 5 sub-clinical cases. Immunohistochemistry using an antibody against Mycobacterium bovis that cross-reacts with MAP (2 cases), and transmission electron microscopy (1 case), revealed myriads of intrahistiocytic mycobacteria. MAP was isolated in one case and detected by PCR in 6 cases. The S type of MAP was identified using a multiplex PCR that distinguishes between S and C types, and PCR-REA. The estimated true within-flock prevalence was ≤ 2.3%. This represents the first communication on within-flock prevalence of JD associated with a type S MAP strain in South America and the second documentation of this strain in the subcontinent. Additional studies are required to better understand the molecular epidemiology of the different MAP types in the region.Centro de Diagnóstico e Investigaciones Veterinaria

Alternativas de manejo nutricional para mejorar la supervivencia de corderos neonatos

La inanición ha sido identificada como la causa más importante de muerte neonatal de corderos en Uruguay (Duran del Campo 1963; Mari, 1979) así como en otros países donde la producción ovina es uno de sus principales rubros (Alexander, 1984). La muerte por inanición puede ser consecuencia de una serie de factores que pueden o no interactuar entre si. Dentro de ellos se encuentran la falta de vigor del cordero recién nacido, falla de la relación madre- hijo, mal comportamiento materno con abandono del cordero por parte de borregas u ovejas con partos laboriosos y prolongados y falta de calostro al momento del parto. Casi todos estos factores se deben a una inadecuada nutrición de la oveja durante el periodo preparto. En éste, la madre tiene altísimos requerimientos para el desarrollo fetal y la glándula mamaria y para la síntesis de calostro. Sin embargo y a pesar del incremento en la demanda de nutrientes, el consumo voluntario de la oveja, sobretodo de forraje, generalmente disminuye durante la última semana de gestación agravando el déficit energético. Esto es aún más grave en condiciones de pastoreo extensivo como las que se registran en los países ovejeros del hemisferio Sur. Una suplementación estratégica de corta duración previo al parto permite revertir el problema ya que las ovejas suplementadas con concentrados energéticos en los últimos días de gestación duplican y hasta triplican la producción de calostro, tienen un mejor comportamiento maternal al parto, el parto puede ser más rápido y en consecuencia sus corderos tienen una mayor sobrevivencia respecto a ovejas alimentadas sólo con forraje

Nutritional management alternatives to improve survival of newborn lambs

Starvation has been identified as the most important cause of neonatal death of lambs in Uruguay as well as in other countries where sheep production is one of its main items. Starvation can be a consequence of a number of factors that may or may not interact with each other. Among them is the lack of vigor of the newborn lamb, failure of the mother-child relationship, maternal misbehavior with the abandonment of the lamb by sheep or lambs with laborious and prolonged deliveries and lack of colostrum at the time of delivery. Almost all of these factors are due to inadequate nutrition of the sheep during the prepartum period. In this, the mother has very high requirements for fetal development and the mammary gland and for colostrum synthesis. However, despite the increase in the demand for nutrients, the voluntary consumption of the sheep, especially forage, generally decreases during the last week of gestation, aggravating the energy deficit. This is even more serious in extensive grazing conditions such as those found in the sheep countries of the southern hemisphere. Strategic supplementation of short duration before calving allows to reverse the problem since sheep supplemented with energy concentrates in the last days of gestation double and even triple colostrum production, have better maternal behavior at calving, calving can be faster and consequently, their lambs have a greater survival compared to sheep fed only with forage

Nicarbazin as an oral contraceptive in eared doves

Eared doves (Zenaida auriculata) are responsible for substantial losses in cereal and oil crops as well as in dairy and feedlot production in the southern cone of South America. Various strategies have been shown to be effective in reducing damage at the farm scale, but in some scenarios, it is necessary to also incorporate population control methods due to excessive bird population size. An alternative approach to reduce pest bird populations is the use of contraceptive methods, minimizing the impact on the environment and non-target populations. Nicarbazin is registered in the United States as a contraceptive for Branta canadensis and Columba livia. The aim of this study was to measure the effect of nicarbazin on the reproductive performance of eared doves in captivity. This study included eleven caged pairs of nesting eared doves in three experimental phases (pre-treatment, treatment, recovery). Each pair was exposed to nicarbazin bait for 4 h per day. The contraceptive used was OvoControlP® (0.5% nicarbazin) ground with a millstone into particles of 0.5–3.0 mm. Daily bait consumption and reproductive variables per pair (egg laying and 14-day-old fledgling) were recorded, and levels of 4,4′dinitrocarbanilide were measured in feces and unhatched eggs. Median consumption was 4.2 g of bait/pair/day. We observed a 62% reduction in the number of viable eggs and successful nestlings in the treatment phasein contrast to pre-treatment (V = 36; p = 0.006). There were no significant differences (V = 0; p = 1) in the number of viable eggs between the pretreatment and recovery phases. Median daily bait consumption by pairs producing zero or one nestling (4.4 and 5.0 g/pair/day respectively) was significantly higher than that of pairs that had two nestlings (3.4 g/pair) during the treatment phase (t = 2.0; p = 0.002). Nicarbazin was effective in reducing reproductive performance of eared doves, and its effect was reversible when the treatment finished

Efeito de dois níveis de energia durante o último terço da gestação de vacas de corte sobre as características da placenta e da prole ao nascimento.

The objective of the present study was to evaluate two energy intake levels during the last third of gestation of beef cows was evaluated on placental characteristics, ethological and morphometric variables of their female calves. Thirty-one British multiparous cows, inseminated at fixed time and carrying females were assigned on Day –90 (Day 0=delivery) to two levels of energy intake until delivery: i- 125% of the requirements (ALTA; n=15) and ii- 75% of the requirements (BAJA; n=16). In the cows, live weight (PV), body condition score (CC), concentration of unesterified fatty acids (AGNE) and insulin were recorded. Placenta (weight, number of cotyledons and placental efficiency) was characterized and morphometric and behavioural measures were evaluated within the first 24 hours of calf life. At calving, BAJA cows had a higher concentration of AGNE (0.45±0.03 vs 0.27±0.03 mmol/L, P<0.01) and lower insulin (8.83±0.73 vs 10.88±0.71 uIU/ml, P<0.03), as well as lower PV (478±15.4 vs 521±11.8 kg, P<0.01) and CC (3.9±0.08 vs 4.5±0.06 u; P<0.01) compared to ALTA cows. The characteristics evaluated in the placentas were not affected by treatments, nor was the PV of the calves at birth. In the same way, none of the morphometric or behavioural variables was significantly affected by the treatments. In the present experiment, the undernourished cows mobilized body reserve during the last third of gestation to protect the integrity of their offspring, verified by the absence of differences in the parameters evaluated. Possibly, cows grazing native pastures develop mechanisms of accumulation and mobilization of body reserves that allow them, at least for the conditions of the present study, to overcome periods of forage shortage as an adaptation strategy.El objetivo del presente trabajo fue evaluar dos niveles de energía en la dieta de vacas para carne durante el último tercio de gestación, sobre características de la placenta, variables etológicas y morfométricas de sus hijas. Treinta y una vacas británicas multíparas, inseminadas a tiempo fijo y gestando hembras fueron asignadas el Día –90 (Día 0=parto) a dos niveles de consumo de energía relativo a los requerimientos de mantenimiento hasta el parto: i- 125% (ALTO; n=15) y ii- 75% (BAJO; n=16). En las vacas se registró peso vivo (PV), condición corporal (CC), concentración de ácidos grasos no esterificados (AGNE) e insulina. Se caracterizaron las placentas (peso, numero de cotiledones y eficiencia placentaria) y se evaluaron medidas morfométricas y comportamentales de las terneras en sus primeras 24 horas de vida. Al parto, las vacas de BAJO presentaron mayor concentración de AGNE (0,45±0,03 vs 0,27±0,03 mmol/L, P<0,01) y menor de insulina (8,83±0,73 vs 10,88±0,71 uIU/ml, P<0,03), así como menor PV (478±15,4 vs 521±11,8 kg, P<0,01) y CC (3,9±0,08 vs 4,5±0,06 u; P<0,01) respecto a las vacas de ALTO. Las características evaluadas en las placentas no fueron afectadas por los tratamientos como tampoco lo fue el PV de las terneras al nacimiento. De la misma forma, ninguna de las variables morfométricas ni comportamentales fue afectada significativamente por los tratamientos. En el presente experimento, las vacas subalimentadas movilizaron reserva corporal durante el último tercio de gestación para resguardar la integridad de sus crías verificado por la ausencia de diferencias en los parámetros evaluados. Posiblemente las vacas pastoreando campo nativo desarrollen mecanismos de acumulación y movilización de reservas corporales que les permite, al menos para las condiciones del presente estudio, sobreponerse a los períodos de escasez de forraje como estrategia de adaptación.O objetivo do presente trabalho foi avaliar dois níveis de energia na dieta de vacas de corte durante o último terço da gestação, sobre as características da placenta, variáveis ​​etológicas e morfométricas de suas filhas. Trinta e uma vacas britânicas multíparas, inseminadas em um tempo fixo e fêmeas em gestação, foram designadas no Dia -90 (Dia 0 = parto) a dois níveis de consumo de energia em relação às necessidades de manutenção até o parto: i- 125% (ALTO; n = 15) e ii- 75% (BAIXO; n = 16). Peso vivo (PV), condição corporal (CC), concentração de ácidos graxos não esterificados (AGNE) e insulina foram registrados nas vacas. As placentas (peso, número de cotilédones e eficiência placentária) foram caracterizadas e medidas morfométricas e comportamentais dos bezerros foram avaliadas nas primeiras 24 horas de vida. No parto, as vacas BAIXAS tiveram uma concentração maior de AGNE (0,45 ± 0,03 vs 0,27 ± 0,03 mmol / L, P <0,01) e insulina mais baixa (8,83 ± 0,73 vs 10,88 ± 0,71 uIU / ml, P <0,03), também como menor PV (478 ± 15,4 vs 521 ± 11,8 kg, P <0,01) e CC (3,9 ± 0,08 vs 4,5 ± 0,06 u; P <0,01) em relação às vacas HIGH. As características avaliadas nas placentas não foram afetadas pelos tratamentos, nem o PV dos bezerros ao nascimento. Da mesma forma, nenhuma das variáveis ​​morfométricas ou comportamentais foi significativamente afetada pelos tratamentos. No presente experimento, as vacas desnutridas mobilizaram reserva corporal durante o último terço da gestação para proteger a integridade de seus bezerros, verificada pela ausência de diferenças nos parâmetros avaliados. Possivelmente vacas em pastagens nativas desenvolvam mecanismos de acumulação e mobilização de reservas corporais que lhes permitem, pelo menos nas condições do presente estudo, superar períodos de escassez de forragem como estratégia de adaptação

Dairy Cows’ Temperament and Milking Performance during the Adaptation to an Automatic Milking System

Adaptative responses of cows to an automatic milking system (AMS) could depend on their temperament, i.e., cows with certain temperament profiles could be able to cope more successfully with the AMS. The relationships between dairy cows’ temperament, behaviour, and productive parameters during the changeover from a conventional milking system (CMS) to an AMS were investigated. Thirty-three multiparous cows were classified as ‘calm’ or ‘reactive’ based on each of the temperament tests conducted: race time, flight speed (FS), and flight distance, at 5, 25, and 45 days in milk at CMS, then the cows were moved from the CMS to the AMS. During the first five milkings in AMS, the number of steps and kicks during each milking were recorded. The daily milk yield was automatically recorded. The number of steps did not vary by temperament classification, but the number of kicks per milking was greater for calm (0.45 ± 0.14) than for reactive cows (0.05 ± 0.03) when they were classified by FS (p p = 0.05). In conclusion, behavioural and productive parameters were influenced by cows´ temperament during the milking system changeover since the calm cows kicked more and produced less than the reactive ones

Fatal Sarcocystis cruzi–induced eosinophilic myocarditis in a heifer in Uruguay

Sarcocystis spp. are causative agents of bovine eosinophilic myositis and/or myocarditis, which are chronic subclinical myopathies that are occasionally responsible for condemnation at slaughterhouses. Sarcocystis cruzi is a protozoan parasite of worldwide distribution transmitted by canids, most commonly associated with subclinical infection in cattle. Although S. cruzi infections can rarely lead to fatal systemic disease, fatal cardiac cases with confirmation of the etiologic diagnosis have not been reported, to our knowledge. We describe herein an unusual case of S. cruzi–induced fatal bovine eosinophilic myocarditis. A 22-mo-old, Holstein–Hereford heifer, in a group of 110 cattle on pasture, manifested growth retardation and died in February 2017. Autopsy revealed myriad yellow-green 1–3-mm coalescing foci, surrounded by fibrosis, affecting ~75% of the ventricular myocardium. Pulmonary edema, ascites, and hydrothorax were consistent with chronic congestive heart failure. Histology revealed severe eosinophilic, granulomatous, necrotizing myocarditis, with multinucleate giant cells, fibrosis, and mineralization. Numerous thin-walled protozoan cysts resembling Sarcocystis spp. were present in the necrotic foci and within the sarcoplasm of adjacent cardiomyocytes. PCR and sequencing of the 18S rRNA gene revealed 99.9–100% homology with S. cruzi. Sarcocystosis can be a rare cause of fatal myocarditis in cattle.Fil: Aráoz, Virginia. Instituto Nacional de Investigación Agropecuaria; UruguayFil: da Silva Silveira, Caroline. Instituto Nacional de Investigación Agropecuaria; UruguayFil: Moré, Gastón Andrés. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Epizootiología y Salud Pública. Laboratorio de Inmunoparasitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Banchero, Georgget. Instituto Nacional de Investigación Agropecuaria; UruguayFil: Riet Correa, Franklin. Instituto Nacional de Investigación Agropecuaria; UruguayFil: Giannitti, Federico. Instituto Nacional de Investigación Agropecuaria; Urugua