Relationship among specific bacterial counts and total bacterial and somatic cell counts and factors influencing their variation in ovine bulk tank milk.

To analyze the relationship among the counts of different organisms and total bacterial count (BTTBC) and somatic cell count (BTSCC) as determined in dairy laboratories in ovine bulk tank milk, 751 bulk tank milk samples from 205 dairy sheep flocks belonging to Consortium for Ovine Promotion (CPO) were collected between January and December 2011. Four samplings were carried out in each flock, once per season, throughout 1 yr. Variables analyzed were bulk tank counts of thermoduric, psychrotrophic, coliform, and gram-positive catalase-negative cocci (GPCNC) bacterial groups.

Factors influencing variation of bulk milk antibiotic residue occurrence, somatic cell count, and total bacterial count in dairy sheep flocks.

To study the variations of bulk tank milk variables in dairy ewe flocks and to identify the main target practices and flock groups to improve milk quality and safety, a total of 71,228 records of antibiotic residue (AR) and milk yield and 68,781 records of somatic cell count (SCC) and total bacterial count (TBC) were obtained over 5 yr from the same 209 dairy ewe flocks of the Assaf breed belonging to the Consortium for Ovine Promotion of Castilla-León (Spain). Based on a logistic regression model, year, month, semester, SCC, TBC, dry therapy, and milk yield significantly contributed to AR variation. High SCC was associated with increased AR violations.

Factors influencing variation of fatty acid content in ovine milk.

Between January 2006 and December 2007, a total of 4,579 test-day observations for contents of milk fatty acids (FA) were obtained from 2,218 lactations of 1,109 ewes belonging to 14 Churra dairy flocks. The 36 analyzed FA were quantified as grams per 100 g of total FA and were grouped as 18 dependent variables: 10 FA, 6 groups of FA, and 2 FA indexes. Flock, day of testing within flock (TD), ewe age, stage of lactation, and season effects contributed significantly to variations in FA.

Short communication: effect of dry therapy using an intramammary infusion on bulk tank somatic cell count in sheep.

A total of 3,141 records of bulk tank milk somatic cell counts (BTSCC) and bulk tank milk total bacterial counts (BTTBC) were obtained over 24 mo from 25 dairy flocks of Assaf ewes belonging to the Consortium for Ovine Promotion in Castilla-León, Spain, in which a complete dry therapy program was carried out in 10,313 ewes using an antibiotic infusion containing 100 mg of penethamate hydriodide, 280 mg of benethamine penicillin, and 100 mg of framycetin sulfate. The selection criteria for all flocks were BTSCC mean values > or =1,000 x 10(3) cells/mL and absence of dry therapy before the start of this experiment. Significant effects on log BTSCC were detected for treatment, milking system, flock within milking system, month within flock by treatment, the interactions treatment by milking system and flock by treatment within milking system, and log BTTBC.

Short communication: Evaluation of the overall accuracy of the DeLaval cell counter for somatic cell count in ovine milk: effect of soak time in diluted and undiluted milk samples.

This study evaluated the performance of the DeLaval cell counter (DCC) when analyzing ovine milk with different soak times (defined as the permanence time of samples within the DCC cassette before starting the DCC counting procedure) in diluted and undiluted milk samples in 2 dairy sheep breeds. A total of 101 composite ovine milk samples (50 from Assaf ewes and 51 from Churra ewes), ranging between 50 x 10(3) and 2,200 x 10(3) cells/mL, were divided into 10 aliquots/milk to be analyzed by DCC. Four undiluted aliquots and 4 aliquots diluted 1:1 in PBS were analyzed by using soak times of 0, 1, 2, and 3 min/aliquot, and the other 2 aliquots were diluted 1:1 in propidium iodide or ethidium bromide staining solutions and analyzed by DCC.