Short communication: Red deer (Cervus elaphus) colostrum during its transition to milk.

We studied changes in chemical composition, somatic cell count, and immunoglobulin G (IgG) and M (IgM) content in red deer (Cervus elaphus) colostrum during the transition to milk at different times after parturition (<5 h, 24 h, 48 h, 2 wk, and 4 wk). The production level was higher at 2 and 4 wk of lactation than during the first day after parturition, with intermediate values at 48 h postpartum. Fat content did not vary during the study period. However, total protein and casein contents were particularly high in the initial 5 h after parturition, decreasing to approximately 50% after 24 h postpartum. Conversely, lactose concentration was low in the beginning (<5 h), increasing gradually throughout the study. Similarly, dry matter dropped during the first 24 h and then remained constant throughout the study. Urea content decreased during the study, showing a slight recovery at 4 wk. Somatic cell count was higher during the first hours after parturition and gradually decreased throughout the study period. The IgG content was higher before 5 h postpartum than at 24 h postpartum. After 5 h, the level of IgG decreased progressively until it reached 0.18 mg/mL at 4 wk of lactation. We observed a similar pattern for IgM content, but it decreased more quickly than IgG and was not detected after 2 wk. In the case of deer, milk should be considered transitional from 24 to 48 h after parturition, and samples collected after 2 wk can be considered mature milk.

Potential application of aromatic plant extracts to prevent cheese blowing.

This study aimed to inhibit the growth of Escherichia coli and Clostridium tyrobutyricum, common bacteria responsible for early and late cheese blowing defects respectively, by using novel aqueous extracts obtained by dynamic solid-liquid extraction and essential oils obtained by solvent free microwave extraction from 12 aromatic plants. In terms of antibacterial activity, a total of 13 extracts inhibited one of the two bacteria, and only two essential oils, Lavandula angustifolia Mill. and Lavandula hybrida, inhibited both. Four aqueous extracts were capable of inhibiting C. tyrobutyricum, but none were effective against E. coli. After extracts' chemical composition identification, relationship between the identified compounds and their antibacterial activity were performed by partial least square regression models revealing that compounds such as 1,8 cineole, linalool, linalyl acetate, ß-phellandrene or verbene (present in essential oils), pinocarvone, pinocamphone or coumaric acid derivate (in aqueous extracts) were compounds highly correlated to the antibacterial activity.

Chemical, microbiological, textural, color, and sensory characteristics of pressed ewe milk cheeses with saffron (Crocus sativus L.) during ripening.

Adding saffron to dairy products represents an innovative practice to introduce them to niche markets. This paper represents a contribution to this field, as few studies have evaluated the influence of this spice on general aspects and ripening parameters of cheese. In this work, pasteurized ewe milk pressed cheeses with saffron were made to study compositional, microbiological, color, textural, and sensory characteristics in relation to saffron concentration and ripening time. The main changes were observed on sensory characteristics and color. In addition, compositional, textural, and microbiological changes could be observed; among them, saffron cheeses were firmer and more elastic but less prone to fracture. A remarkable result that could lead to further studies is that saffron addition slightly slowed down growth of total and lactic acid bacteria. This resulted in a slightly lower rate of pH decrease during pressing and, as a consequence, lower salt and water content. Compositional differences were not evident by the end of the ripening period.

Short communication: Occurrence of aflatoxin M1 in the Manchego cheese supply chain.

The importance of ewe milk lies in the production of high quality cheeses, such as Manchego cheese with a Protected Designation of Origin, whose safety must be guaranteed. In a 2-yr study, 407 bulk tank milk samples from farms and 82 silo milk and curd samples from cheese factories were collected from southeast Spain and tested for aflatoxin M1 (AFM1) using 2 commercial ELISA tests. Of these, 99.3% of the bulk tank samples had AFM1 levels below the European Union (EU) legal limit for milk (50 ng/kg), and well below the limit adopted by the Codex Alimentarius (500 ng/kg). Moreover, 98.8% of the silo milk and curd samples from cheese factories had AFM1 levels below the EU limit for milk. When considering median AFM1 concentrations, an average 4-fold increase was found in the final curd in relation to the corresponding silo milk. Control of AFM1 in Manchega ewe milk would enhance dairy product safety by the possible detection of faults in the manufacture of Manchego cheese.

Short communication: antibiotic residues in milk following the use of intravaginal sponges for estrus synchronization in dairy ewes.

The addition of antibiotics to intravaginal sponges used to synchronize ewe estrus is currently a recommended practice for the prevention of posttreatment vaginal infections. Application of this antibiotic treatment is usually done without withdrawal periods for milk, but official pharmaceutical instructions do not consider the extra-label use of antibiotics, which could result in the presence of antibiotic residues in milk. To understand the effects of the use of antibiotics on the performance of these hormonal treatments, milk collected from a group of Manchega ewes estrus synchronized by intravaginally inserted progestagen sponges jointly impregnated with antibiotics (benzyl penicillin procaine: 1,000,000 IU/25 sponges plus DH-streptomycin: 1 g/25 sponges) was evaluated for antibiotic residue persistence with 5 types of antibiotic screening tests (BRT, Copan CMT, Delvotest MSC, Eclipse 100, and New SNAP Beta-Lactams). Time to antibiotic residue depletion was established by a logistic regression model, and a significant response to milking order was observed in all methods. Positive or doubtful tests were observed after the insertion of intravaginal sponges for all assay screening tests at the time of the first milking and sometimes afterwards.

Lipid oxidation in lamb meat: Effect of the weight, handling previous slaughter and modified atmospheres.

This study examined the effect of pre-slaughter handling (electrical, gas (CO(2)) or non-stunning) on lipid oxidation (as thiobarbituric acid reactive substances, TBARS; in the unit of mg malondialdehyde/kg(-1) of meat) of Spanish Manchega breed lamb meat, at 24h and at 7 days post-mortem. Lambs were slaughtered at two different weights (light (L), 25kg, vs. suckling (S), 12.8kg). In general gas-stunned lambs had lower lipid oxidation (P<0.001), and it was higher (P<0.001) in light lambs compared to suckling lambs. In both groups (S and L), malondialdehyde level increased with time (P<0.001), although this increase was lower (P<0.05) in gas-stunned suckling lambs. In addition, we evaluated the effect of stunning methods (TS: electrical vs. gas) and the weight (L vs. S) on lipid oxidation values in samples packed in different types of modified atmosphere (MA: A: 70%O(2)+30%CO(2); B: 69.3%N(2)+30%CO(2)+0.7%CO; C: 60%N(2)+40%CO(2)) at 7, 14 and 21 days post-packing. Values were higher in samples with MA-type A and lower in B and C types (P<0.05). A significant interaction (P<0.001) weight×TS was observed and the lowest rates of TBARS were found in the samples of light lambs stunned with gas and packed under anaerobic conditions (MA-B and C).

Screening of antibiotic residues in ewes' milk destined to cheese by a commercial microbiological inhibition assay.

Bulk ewes' milk from Spanish dairy farms in the Castilla-La Mancha region and destined for production of protected denomination of origin (PDO) Manchego cheese were analysed each month for antimicrobial residues during the course of 1 year. A microbiological assay specific for ewes' milk (Eclipse '100ov') was used. The number of positive samples by the Eclipse '100ov' test was 2.6%. A second examination of positives following heat treatment at 82 degrees C for 10 min showed a reduction of up to 0.9% (i.e. 63% of the samples detected corresponded to 'false-positives'). Of the confirmed positives, 25% were identified as beta-lactams by a penicillinase solution; the remainder corresponded to antimicrobial compounds that could not be identified. The month of collection was related to the probability of positive results, but to no other factors such as somatic cell counts, bacteriology or composition (fat and protein). The highest rates of positives were observed in September and October. Finally, the results were compared with those obtained by the Delvotest SP method, which showed the detection of a higher number of positive samples compared with the Eclipse '100ov' method.

Effects of birth date and order in lactation performance of Iberian red deer (Cervus elaphus hispanicus).

This study discriminated between 2 effects (birth date and presence of older calves) assessed jointly in previous studies. Birth date delay produced similar effects to those reported previously: reduced milk and milk nutrient production in late-calving hinds, concentration of milk, substitution of protein by fat, greater body weight losses of dams (hinds), and reduced calf growth. Hinds in a group consisting of early- and late-born calves produced more milk, and calves grew more than their isolated counterparts. Evidence exists for consequences of foster suckling by early-born calves in mixed groups of early- and late-born calves at the end of the standard birth period, because these calves grew more than predicted by the milk production of their dams. In contrast, no detrimental effect was found in late-born calves of this group. Lack of differences might be due to the excess of hind milk production during the first 5 wk of lactation previously recorded in other experiments.

Meat quality in suckling lambs: effect of pre-slaughter handling.

Thirty-three suckling lambs of the Manchega breed were used to compare the effects of pre-slaughter handling (PSH) on initial meat quality and at 7 days post-mortem. Lambs were distributed into three groups: electrically stunned (ESL; n=15), stunned using CO(2) (GSL; n=10) and slaughtered without previous stunning (USL; n=8). Meat quality was evaluated by examining pH, colour (L*, a*, b* values), water holding capacity (WHC), cooking loss (CL), shear force (SF) and drip loss (DL). At 24 h post-mortem, the highest pH corresponded to the USL group (P<0.05) whereas the lowest pH decline (pH(0)-pH(24)) corresponded to the GSL group (P<0.05). Differences in pH among groups disappeared after 7 days post-mortem. In general, PSH did not affect values of WHC, CL and colour parameters. After 7 days post-mortem, there were significant differences between groups in DL, this being lowest (P<0.05) in stunned animals. GSL resulted in more tender meat (lower SF value) than ESL and USL (P<0.05). Moreover, there was no blood splash in any of the carcasses of the GSL group.

Occurrence of antibiotic residues in milk from Manchega ewe dairy farms.

Ewe milk samples from different ovine dairy farms from the Castilla-La Mancha region of Spain were collected from bulk tanks to estimate the occurrence of antibiotic residues in raw and heated (82 degrees C, 10 min) milk by the Delvotest SP test. The month of collection, somatic cell counts, and bacteriology were analyzed and examined by means of a logistic regression model. The screening of a total of 2686 raw milk samples showed 1.7% "positive" and 2.1% "doubtful" results, which decreased after heating treatment to 1.3% and 0.4%, respectively. "Positive" and "doubtful" samples were identified by penicillinase and p-aminobenzoic acid solutions, and the majority of them corresponded to antimicrobials different than beta-lactams or sulfonamides. By applying a logistic regression model, a significant effect of month of collection and bacteriology was observed in the initial screening and after the heat treatment. The highest percentages of "positive plus doubtful" results were observed in late summer-early autumn. A slight peak was also observed in spring in raw milk samples. Bacteriology was positively correlated with "positive plus doubtful" results.

Lactation under induced five-month delay reproduction in Iberian red deer (Cervus elaphus hispanicus).

In Iberian deer, calf birth date affects both milk production and composition, as well as the weight change of hind during lactation and calf growth. This study examines a five-month induced delay in calving (autumn group) in a group of 19 Iberian hinds compared to a group of 13 standard calving hinds (spring group). Fertility in the autumn group was half that of the spring one. From the former, a further two calves out of six died before or soon after birth. Successfully lactating hinds showed a greater concentration in protein, fat and lactose (P < 0.001), but did not differ from spring group in total milk yield, calf gain or weight change of hinds during lactation. However, after correcting for the greater calf or hind body weight at calving of the autumn group, this group showed lower values for these variables than the spring group. Results show that at least in Iberian deer, counter-season reproduction is possible, and that the effects on lactation variables are similar to those of a natural delay in calving.

Performances of antibiotic screening tests in determining the persistence of penicillin residues in ewe's milk.

Milk collected at 12-h intervals throughout 6 days from three groups of Manchega ewes (n = 12 per group), treated intramuscularly with beta-lactams (benzyl penicillin procaine, ampicillin, and amoxicillin, respectively), was evaluated for antibiotic residue persistence with four microbial inhibitor tests (BRT MRL, CH ATK P&S, Delvotest SP, and Eclipse 100ov) and one enzymatic test (Penzym 100). Antibiotic depletion time was established using a logistic regression model. A clear effect (P < 0.0001) of milking order on the response of all tests was observed with the three antibiotics, but no significant effects were found for milk yield. Except with Eclipse 100ov, positive tests were observed after the recommended withdrawal period of benzyl penicillin procaine (five milkings) from 2% (Delvotest SP) to 11% (CH ATK P&S). There were almost no positive responses beyond the withdrawal period (six milkings) of ampicillin, except for the Penzym 100 test (7%). Residues of amoxicillin were found to persist beyond the six milkings established as the withdrawal period, from 2.8% (Eclipse 100ov) to 72.4% (CH ATK P&S) of positive cases. Higher frequencies of doubtful cases were found with BRT MRL and Delvotest SP assays with the three beta-lactams. Positive and doubtful results could be obtained when milk samples from individual ewes were analyzed using BRT MRL, CH ATK P&S, Delvotest SP, and Penzym 100 tests, even if farmers follow the antibiotic withdrawal periods.