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. After dry therapy was implemented, log BTSCC decreased significantly in machine-milked flocks (5.95 +/- 0.007) compared with values before antibiotic treatment (6.13 +/- 0.008). The effect was observed at the beginning of the second lactation posttreatment (5.98 +/- 0.013). However, dry therapy was not effective in hand-milked flocks, suggesting poor hygiene conditions. A significant relationship was found between BTSCC and BTTBC; therefore, programs for improving milk hygiene should be implemented for both BTSCC and BTTBC variables at the same time.

Short communication: bulk tank total bacterial count in dairy sheep: factors of variation and relationship with somatic cell count.

A total of 9,353 records for bulk tank total bacterial count (TBC) were obtained over 1 yr from 315 dairy ewe flocks belonging to the Sheep Improvement Consortium (CPO) in Castilla-León (Spain). Analysis of variance showed significant effects of flock, breed, month within flock, dry therapy, milking type and installation, and logSCC on logTBC. Flock and month within flock were important variation factors as they accounted for 22.0 and 22.1% of the variance, respectively. Considerable repeatability values were obtained for both random factors. Hand milking and bucket-milking machines elicited highest logTBC (5.31), whereas parlor systems with looped milkline (5.01) elicited the lowest logTBC. The implementation of dry therapy practice (5.12) showed significantly lower logTBC than when not used (5.25). Variability in logTBC among breeds ranged from 5.24 (Awassi) to 5.07 (Churra). However, clinical outbreaks of contagious agalactia did not increase TBC significantly. A statistically significant relationship was found between logTBC and logSCC, the correlation coefficient between the variables being r = 0.23. Programs for improving milk hygiene should be implemented for both total bacterial count and somatic cell count variables at the same time.

Factors of variation influencing bulk tank somatic cell count in dairy sheep.

Between January and December 2002, a total of 21,685 records for bulk tank milk somatic cell count (BTSCC) were obtained from 309 dairy ewe herds belonging to the Sheep Improvement Consortium in Castilla-Leon, Spain. Based on the first statistical model, ANOVA detected significant effects of herd, breed, month within herd, dry therapy, type of milking, contagious agalactia, and installations within machine milking on logBTSCC. A second statistical model was used on herds with machine milking to study the effect of the vacuum level and pulsation rate on BTSCC. Herd and month within herd were important variation factors as they explained 48.4 and 16.1% of the variance in BTSCC. Variability in logBTSCC among breeds ranged from 5.84 (Castellana) to 6.09 (Awassi and Spanish Assaf). Implementing dry-ewe therapy (5.91) significantly reduced logBTSCC compared with when it was not implemented (6.10). Hand milking elicited greater logBTSCC (6.07) than machine milking (5.94). Machine milking of ewes in milking parlors (logBTSCC: 5.88 to 5.94) was associated with better udder health than was the use of bucket-milking machines (6.04). Reduced vacuum levels and elevated pulsation rate during machine milking optimized BTSCC. In all cases, clinical outbreaks of contagious agalactia increased BTSCC. As a result, dry therapy was proposed as the main tool to reduce BTSCC. Optimization of milking-machine standards and parlor systems also improved udder health in dairy sheep.

Leaf senescence is delayed in tobacco plants expressing the maize homeobox gene knotted1 under the control of a senescence-activated promoter.

Leaf senescence is an active process involving remobilization of nutrients from senescing leaves to other parts of the plant. Whereas senescence is accompanied by a decline in leaf cytokinin content, supplemental cytokinin delays senescence. Plants that overexpress isopentenyl transferase (ipt), a cytokinin-producing gene, or knotted1 (kn1), a homeobox gene, have many phenotypes in common. Many of these phenotypes are characteristic of altered cytokinin physiology. The effect of kn1 on leaf senescence was tested by driving its expression using the promoter of the senescence-associated gene SAG12. SAG:kn1 tobacco plants showed a marked delay in leaf senescence but otherwise developed normally. The delay in senescence was revealed by an increase in chlorophyll content in SAG:kn1 leaves relative to leaves of the control plants and by a decrease in the number of dead leaves. Senescence was also delayed in detached leaves of SAG:kn1 plants. Delayed senescence was accompanied by increased leaf cytokinin content in older leaves expressing kn1. These experiments extend the current understanding of kn1 function and suggest that in addition to mediating meristem maintenance, kn1 is capable of regulating the onset of senescence in leaves.

[Iron storage in infants at 2 and 8 months of age]. / Estudios de la reserva de hierro en el lactante menor a los dos y ocho meses de edad.

For to establish the probability of the early identification of the iron deficient in the infant, we evaluate the correlation between the serum ferritin (SF) values at two and eight months of age. It included 57 infants, 30 cases with SF higher than 20 ng/mL (group I), eight cases with SF between 12-20 ng/mL (group II) and 19 infants with SF lower of 12 ng/mL (group III); the addition of two late groups result in 27 cases with SF lower of 20 ng/mL (group IV). None cases had SF lower 20 ng/mL at two months of age. The correlation between SF values and hemoglobin (Hb) at two and eight months of age, the Hb of the infants deficients had better correlation (0.602 P = 0.006). The SF not had statistic correlation. For to establish if the groups had the same values of SF and Hb at two months on age, the SF values were in the group III vs group I were 154.1 and 274.6 ng/mL (P = 0.004) respectively. This data indicate that the infants that development severe iron deficiency to eight months of age, may predict this quantify the SF at two months of age.