Characterisation of proteolysis profile of Argentinean sheep cheeses made by two different production methods.

BACKGROUND: In this work the proteolysis profiles of Argentinean sheep cheeses made by two different production methods were studied in order to develop products with typical and defined features. Cheeses with a starter of Streptococcus thermophilus, curd cut to corn grain size, washed and heated to 43 degrees C (S cheeses) and cheeses with a mixed starter of Streptococcus thermophilus, Lactobacillus helveticus and Lactobacillus bulgaricus, curd cut to rice grain size, unwashed and heated to 47 degrees C (L cheeses) were manufactured. The cheeses were ripened at 12 degrees C and 80% relative humidity for 180 days and samples were taken throughout this period. RESULTS: Gross composition and primary proteolysis were similar for both types of cheeses. Streptococci counts diminished from 10(9) to 10(7) colony-forming units g(-1) during ripening in both S and L cheeses. Lactobacilli counts in L cheeses decreased during ripening and disappeared at 180 days. L cheeses had significantly lower pH values and showed higher peptidolysis than S cheeses. Triangle sensory evaluation indicated important differences between the two types of cheeses. CONCLUSION: S cheeses had a low proteolysis level and a soft flavour, making them appropriate for consumption after a short ripening time. L cheeses had a higher proteolysis level and more intense sensory characteristics, making them appropriate for consumption after a longer ripening time.

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 ...

Pattern of eprinomectin milk excretion in dairy sheep unaffected by lactation stage: comparative residual profiles in dairy products.

Eprinomectin (EPM) is a broad-spectrum endectocide compound approved for use in dairy cattle with a zero milk-withdrawal period, but has not been registered for use in lactating dairy sheep. The pattern of EPM excretion in milk was comparatively characterized following its pour-on administration (500 microg/kg) to lactating dairy sheep at two different stages of lactation. The relationship between milk excretion and plasma disposition kinetics of EPM was characterized. Residual EPM concentrations were assessed during cheese making (whey and curd) and ripening (cheese) by high-performance liquid chromatography and fluorescence detection. EPM was poorly distributed from the bloodstream to the mammary gland and low concentrations were excreted in milk. The level of milk production (early-mid and mid-late lactation) did not affect either the plasma-milk distribution or the pattern of residual concentrations in milk. During cheese making, the highest residual concentrations of EPM were measured in the curd, which increased during cheese ripening, reaching a maximum after 40 days. However, these residual concentrations were below the maximum residue limit of 20 ng/ml established for EPM in bovine's milk. Therefore, these dairy products could be considered safe for consumers after the EPM antiparasitic pour-on treatment (500 microg/kg) in lactating dairy sheep.

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.