Condiciones de alojamiento de los terneros en crianzas artificiales de tambo y su relación con el estrés por frío / Housing conditions of dairy calves and its relationship with cold stress

Resumen El estrés por frío en los terneros puede ser muy perjudicial para su salud y rendimiento futuro. El objetivo del presente trabajo fue evaluar el efecto de las condiciones de manejo de la crianza artificial y su relación con estrés por frío en terneros de tambo. Se evaluaron 160 terneros durante las primeras horas de la mañana, y se registró si los animales poseían capa o no y si disponían o no de cama. Se observó si contaban con reparo para limitantes climáticas. También se registró la temperatura rectal y si temblaban o no. Se consideró que terneros con temperatura rectal igual o inferior a 37,2 °C se encontraban en estrés por frio. El análisis estadístico de los datos se hizo mediante la prueba no paramétrica de Chi cuadrado y se calculó la probabilidad de ocurrencia mediante Odds Ratio. Encontrándose que los terneros en condiciones de estrés presentaron 4,93 veces mayor probabilidad de temblar; que disponer de cama fue favorable para prevenir el estrés (0,027), que las capas plásticas incrementaron la probabilidad de sufrir de estrés (0,006) y que proveer reparo a los animales tiene un efecto positivo en la prevención del estrés por frío (p = 0,027) en los terneros de tambo.

Abstract Cold stress in calves can be very detrimental to their health and performance. The aim of this work was to evaluate the effect of artificial rearing management conditions and their relationship to cold stress in dairy calves. A total of 160 calves were evaluated during the early morning hours and it was recorded whether or not the animals had cape and whether or not they had bed in pens. Also, it was observed if they had protection for climatic limitations. Rectal temperature and whether or not they were shivering were also recorded. Calves with rectal temperature equal to or lower than 37.2 °C were considered to be in cold stress. The statistical analysis of the data was performed using the non-parametric Chi-square test and the probability of occurrence was calculated using Odds Ratio. It was found that calves under stress conditions were 4.93 times more likely to shiver; that having bed in pens was favorable for preventing stress (0.027), that plastic cape increased the probability of suffering from stress (0.006) and that providing shelter to animals had a positive effect on the prevention of cold stress (p = 0.027) in dairy calves.

Dinámica de contaminación de pasturas con huevos de nematodos gastrointestinales de bovinos en el Valle de Lerma, Salta / Dynamics of pasture contamination with bovine gastrointestinal nematode eggs in the Lerma Valley, Argentina

Resumen El Valle de Lerma (VDL) es una región ubicada en la parte central de la provincia de Salta, República Argentina, la cual da origen a la mayor parte de la producción láctea provincial. La nematodiasis gastrointestinal es uno de los problemas sanitarios de mayor impacto económico en los sistemas productivos de base pastoril. El objetivo de este trabajo fue caracterizar la variación estacional de la eliminación de huevos y géneros de nematodos al medio ambiente. Mensualmente se tomaron muestras de materia fecal en bovinos de recría para conteo de huevos por gramo (HPG) y coprocultivo para determinación de géneros en tres establecimientos ganaderos de la región. En todos ellos se observaron dos picos en los valores medios de HPG, que ocurrieron entre principios de verano y fines de otoño. Los géneros/especies más prevalentes fueron Cooperia pectinata, Haemonchus spp. y Cooperia punctata, seguidos por Oesophagostomum spp., Trichostrongylus spp. y Ostertagia spp. Estos resultados aportan nueva evidencia al conocimiento de la epidemiología de los nematodos gastrointestinales de los bovinos en la región del VDL.

Abstract The Lerma Valley (LV) is a region located in the central part of the province of Salta, Argentine Republic. The largest dairy production in the province originates in this region. Gastrointestinal nematodiasis is one of the health problems with the greatest economic impact in pastoral-based production systems. The objective of the present work was to characterize the seasonal variation of the elimination of eggs and genera of nematodes to the environment. Fecal matter samples were taken from rearing cattle to count eggs per gram (Epg) and culture for gender determination monthly in three farms in the region. In these, it was possible to observe that the Epg values ​​showed two peaks, which occurred between the beginning of summer and the end of autumn. Regarding the genera/species, the most prevalent were Cooperia pectinata, Haemonchus sp. and Cooperia punctata, followed by Oesophagostomum spp., Trichostrongylus spp. and Ostertagia spp. These results contribute with new evidence to the knowledge of the epidemiology of gastrointestinal nematodes of cattle in the LV region.

Single nucleotide polymorphisms from candidate genes associated with nematode resistance and resilience in Corriedale and Pampinta sheep in Argentina.

Selective breeding of genetically resistant animals is considered a promising strategy to face the problem of nematode resistance to anthelmintics and mitigate concerns about the presence of chemical residues in animal food products and the environment. Gastrointestinal nematode resistance is a complex, multifactorial trait related to host immunity. However, the mechanisms underlying host resistance and response to infection remain to be fully elucidated. In this context, the objective of this study was to provide insight into the chromosomal regions determining nematode resistance and resilience in Corriedale and resistance in Pampinta sheep breeds. A total of 170 single nucleotide polymorphisms (SNP) from 76 candidate genes for immune response were studied in 624 Corriedale and 304 Pampinta animals. Lambs underwent artificial or natural challenges with infective larvae mainly from Haemonchus contortus. Fecal egg counts, estimated breeding values for fecal egg counts, and rate of packed cell volume change and FAMACHA© score change over the challenge were used, when available, as indicators of host parasite resistance or resilience. Phenotype-genotype association studies were conducted and significance values obtained were adjusted for multiple testing errors. Eight SNPs, located on OARs 3, 6, 12, and 20, reached significance in Corriedale sheep under artificial challenge. Those SNP represent allelic variants from the MHC-Ovine Lymphocyte Antigen-DRA, two C-type lectin domain families, the Interleukin 2 receptor ß, the Toll-like receptor 10, the Mannan binding lectin serine peptidase 2, and the NLR family, CARD domain containing 4 genes. On Pampinta lambs under natural challenge, we found three significant SNPs, located in the TIMP metallopeptidase inhibitor 3, the FBJ murine osteosarcoma viral oncogene homolog, and the Interleukin 20 receptor alpha genes, on OARs 3, 7, and 8, respectively. The results obtained herein confirm genomic regions previously reported as associated with nematode resistance in other sheep breeds, reinforcing their role in host response to parasites. These findings contribute to gain knowledge on parasite resistance and resilience in Corriedale sheep and report for the first time SNPs associated with resistance to gastrointestinal parasite infections in Pampinta breed.

Effect of gastrointestinal nematodes on serum copper and phosphorus of growing beef calves in northwestern Argentina.

The aim of this work was to study the effect of gastrointestinal nematodes (GINs) on copper (Cu) and phosphorus (P) in blood of beef cattle in two ranches (R1 and R2) located in northwestern Argentina. In 2015-2016 (R1) and 2016-2017 (R2), in each ranch, 22 weaned female calves were divided into two groups: calves treated systematically with 200 mcg/kg moxidectin every 45-50 days (TG) and untreated calves (UTG). The following parameters were measured: number of fecal eggs (epg), fecal cultures, serum Cu and P levels, and live weight gain (LWG). Differences between groups were compared using analysis of variance and Tukey test. GIN infections in both ranches were subclinical and moderate, showing the highest epg (R1 = 907 ± 754; R2 = 1049 ± 1040) by mid-winter. Epg values of TG groups were always negligible (> 93% of moxidectin efficacy). The dominant nematode genera were Cooperia and Haemonchus. The average serum Cu values (µg/dl) indicated low (R1 = 49.7 ± 18) and severe (R2 = 27.2 ± 14) deficiency. The effect of treatments was evident in both ranches from late winter, with TG showing significantly (p < 0.01) higher serum levels in winter, spring, and early autumn (R1 = 65.1, 50.9, and 60.3; R2 = 48.0, 25.7, and 22.4) than UTG (R1 = 44.3, 33.9, and 32.9; R2 = 25.5, 18.2, and 16.4). There were no differences in serum P levels between groups. LWG of TG increased significantly (p < 0.008) (27.2% in R1 and 38.6% in R2), with respect to those of UTG. This study showed a negative effect of GIN on serum Cu values in moderately infected growing calves.

Epidemiology and effect of gastrointestinal nematodes on dairy goats in Argentina.

The aim of this work was to study the epidemiology and harmful effects of gastrointestinal nematodes (GINs) on dairy goats maintained in an intensive system. Two groups of goats were studied: untreated group (UG) (subdivided into UGjun goats that kidded in June, and UGjul goats that kidded in July) and treated group (TG) (with no subgroups, treated with monepantel: 3.75 mg/kg, orally, monthly). Eggs per gram (epg) in faeces were counted, faecal culture was performed to differentiate nematode genera and milk production was measured. Differences between groups were compared using least squares means analysis of variance (milk production and milking period length) and Kruskal-Wallis test (faecal egg counts). Nematode infection was moderate, with Haemonchus and Trichostrongylus being the dominant genera; the faecal egg counts reached the level of 2000 only once throughout the study. Goats that kidded in June had higher egg count after parturition (UGjun = 1564 epg), with significant differences (p < 0.04) from those that still had not kidded (UGjul = 962 epg). Over the entire trial period, the mean total milk production of TG (399.5 L ± 34.0 L) was significantly higher (p < 0.05) than that of UG (281.6 L ± 37.5 L), representing an increase of 41.8% in total milk yield. The results of this study show a post-partum peak in egg count and a negative effect of GINs on milk yield, even with moderate infections.

Health management practices and disease prevalence in dairy sheep systems in Argentina / Práticas de manejo sanitário e frequência de doenças em ovinos leiteiros na Argentina

A cross-sectional survey of 19 dairy sheep farms in Argentina was carried out with the purpose to know farm management, health practices, and occurrence and mortality of diseases. The survey comprised 40 percent of all sheep milking farms in Argentina. A questionnaire was conducted by way of personal interviews with sheep owners during farm visits. The proportions of farms reporting routine vaccination for clostridial diseases, contagious ecthyma, pneumonia and mineral and vitamin parenteral administration were 63 percent, 47.3 percent, 16.6 percent and 42.1 percent respectively. Regular treatment against lice was used in 37.5 percent of the farms, and 89.5 percent o the farmers treated against gastrointestinal nematodes (GIN). The mean number of GIN drenches per farm was 2.26±1.78 annually. In 68.4 percent of the milking flocks the California Mastitis Test was regularly done and 55.6 percent of the farmer managers had sampled their flocks once a year for Brucella ovis antibodies. During the pre-mating period respectively 68.4 percent and 50 percent of farmers clinically examined their rams and ewe for general health and teeth condition. The udders of ewes were frequently inspected at the start of each milking period. The most important parasite problems noticed were GIN (reported by 57.9 percent of farmers), lice (57.9 percent) and scabies (10.5 percent) and the most frequent infectious diseases were ecthyma (73.7 percent), pneumonia and other respiratory problems (57.9 percent), clinical mastitis (55.6 percent), clostridial diseases (36.9 percent) and foot lameness (35.2 percent). Photosensitivity (47.4 percent) and ruminal acidosis (42.1 percent) were reported as other frequent toxic or metabolic disorders. Owners mentioned that the mean lifespan or milk productive time per ewe was 4.5±1.4 years. Perinatal lamb mortality was 8.5 percent and the total flock mortality rates, above the first 24 h of life was 6.9 percent. ...

Foi realizado um levantamento longitudinal em 19 fazendas de ovinos leiteiros na Argentina com o objetivo de conhecer práticas de manejo, medidas sanitárias e ocorrência e freqüência das enfermidades. O levantamento incluiu 40 por cento de todas as fazendas do país que produzem leite ovino. Um questionário foi utilizado com entrevistas pessoais com os ovinocultores durante visita às fazendas. A percentagem de fazendas que relataram vacinação rotineira contra clostridioses, ectima contagioso, pneumonia e administração parenteral de minerais e vitaminas foi 63 por cento, 47,3 por cento, 16,6 por cento e 42,1 por cento, respectivamente. Parte dos produtores (37,5 por cento) realizava tratamento regularmente contra piolhos e 89,5 por cento contra nematódeos gastrintestinais. O número médio de tratamentos anti-helmínticos anuais, por fazenda, era de 2,26+1,78. Em 68,4 por cento dos rebanhos leiteiros o Califórnia Mastite Teste (CMT) era regularmente realizado e 55,6 por cento dos produtores colhiam amostras de seus rebanhos uma vez por ano para diagnóstico de Brucella ovis. Durante o período de pré-acasalamento 68,4 por cento e 50 por cento dos produtores examinavam clinicamente seus carneiros e a condição geral e de dentes de suas ovelhas. O úbere das ovelhas era geralmente inspecionado no início da ordenha. Os principais problemas parasitários eram nematódeos gastrintestinais (mencionado por 57,9 por cento dos produtores), piolhos (57,9 por cento) e sarna (10,5 por cento) e as doenças infecciosas mais frequentes foram ectima contagioso (73,7 por cento), pneumonia e outros problemas respiratórios (57,9 por cento), mastite clínica (55,6 por cento), clostridioses (36,9 por cento) e laminite (35,2 por cento). Fotossensibilização (47,4 por cento) e acidose ruminal (42,1 por cento) foram relatadas como as principais desordens tóxicas ou metabólicas. Na visão dos produtores, a expectativa de vida produtiva ou o tempo de produção de leite por ovelha ...

Effects of faecal residues of moxidectin and doramectin on the activity of arthropods in cattle dung.

Dung invertebrate colonization and degradation levels of faeces from cattle treated with endectocides were studied. Faeces of control and doramectin (DRM) (subcutaneous) and moxidectin (MXD) (subcutaneous and topical) treated animals were deposited on the field from 3 to 21 days post-treatment (pt). Pats were recovered after 6 to 42 days post-deposition (pd). Faecal weight, dry matter, arthropods number, and drugs concentrations were determined. Total arthropods number was higher in control (P<0.0001) than in the other groups from days 3 to 21 pt. Total number of insects recovered on days 3, 11, and 21 pt from control pats was significantly (P<0.001) higher than in treated-animal pats during all the trial. At day 21 pt, the insects' number in dung voided by DRM-treated cattle was (P<0.05) lower than in the other groups. Comparisons of dung degradation among treatments were inconclusive. A lower adverse effect was observed for MXD compared with DRM. No significant degradation of MXD or DRM was observed during the present trial.

An efficient one-pot synthesis of tethered cyclohexadiene enaminonitriles from methyl-ketones: an effective route to quinazolines.

The quinazolines represent a useful natural product scaffold with demonstrated activities against disorders such as high blood pressure and benign prostatic hyperplasia. Here we report on the synthesis and biological activity of a series of quinazolines that were prepared by a one-pot synthesis of substituted cyclohexadiene enaminonitriles from methyl-ketones. The approach, which employs NaH, complements published procedures where LDA is utilized. While the NaH catalyzed reaction generates the cyclohexadiene enaminonitriles in high yields with heterocyclic substrates, the reaction fails to promote product formation of aliphatic alkyl substrates. On the contrary, the LDA mediated synthesis favors the long chain alkyl substituents while reactions involving the aromatic substrates result in low yields. The final conversion to the quinazolines is also a modification on literature protocols. In cellular assays, the quinazolines showed the most promising activity against Jurkat with CC(50) values in the low micromolar range. Weak activity was observed against microbial strains (Bacillus subtilis, Escherichia coli, and Saccharomyces cerevisiae). The substituted enaminonitrile intermediates also exhibited weak anti-microbial activity and cytotoxicity against human T-cell leukemia.

Milk excretion of ivermectin and moxidectin in dairy sheep: assessment of drug residues during cheese elaboration and ripening period.

Ivermectin (IVM) and moxidectin (MXD) are broad-spectrum endectocide antiparasitic drugs extensively used in food-producing animals. The patterns of IVM and MXD excretion in milk were comparatively characterized following their subcutaneous administration (200 microg.kg(-1) of body weight) to lactating dairy sheep. The relationship between milk excretion and plasma disposition kinetics of both compounds was characterized. A pool of milk collected from all of the animals in each experimental group was used for cheese elaboration. IVM and MXD residual concentrations were assessed during the cheese-making process and ripening period. IVM and MXD concentrations were measured in plasma, milk, and milk product (whey, curd, and cheese) samples using an HPLC-based methodology with fluorescence detection. IVM and MXD were extensively distributed from the bloodstream to the mammary gland, and large quantities, particularly of MXD, were excreted in milk. Residual concentrations of both compounds were recovered in milk up to 30 (IVM) and 35 (MXD) days post-treatment. The total fraction of the administered dose excreted in milk for MXD was significantly higher than that of IVM. During cheese production, the highest residual concentrations of both molecules were measured in the curd. Thirty-four percent of the total drug residue measured in the pooled milk collected from treated sheep was lost during the cheese-making process. The lowest residual concentrations were measured in the whey. IVM and MXD concentrations in the elaborated cheese tended to increase during the ripening period, reaching the highest residual level at 40 days of cheese maturation. The long persistence of milk residual concentrations of MXD and IVM in lactating dairy sheep and the high concentrations found in cheese and other milk-related products should be seriously considered before recommendation of the extralabel use of these antiparasitic drugs in dairy animals.