Modification of IgE binding during heat processing of the cow's milk allergen beta-lactoglobulin

The effect of heat treatment on the IgE binding ability of beta-lactoglobulin, as pure protein or in whole milk, was studied by inhibition of IgE antibody binding using FEIA-CAP inhibition. A slight but significant decreased IgE binding was seen between unheated and heat-treated beta-lactoglobulin solution at 74 degrees C (IC(50) = 2.03 and 3.59 microg/mL, respectively, p = 0.032). A more pronounced decrease was found at 90 degrees C with an IC(50) of 8.45 microg/mL (p = 0.014). The inhibition of IgE binding of milk after heat treatment at 90 degrees C was also significantly decreased (p = 0.007). However, at all heat treatments, a similar total amount of IgE antibodies could be inhibited at a sufficiently high concentration of beta-lactoglobulin. The inhibiting ability of beta-lactoglobulin was significantly impaired in some fermented acidified milk products such as yogurt as compared to that in nonfermented milk (p < 0.001). There was only a small difference of IgE binding between the native forms of genetic variants A and B.     

Molecular water motions of skim milk powder solutions during acidification studied by 17O and 1H nuclear magnetic resonance and rheology

The molecular motion of water was studied in glucono-δ-lactone-acidified skim milk powder (SMP) solutions with various pH values and dry matter contents. NMR relaxometry measurements revealed that lowering the pH in SMP solutions affected 17O and 1H T2 relaxation rates almost identically. Consequently, the present study indicates that the proteins present in the samples do not affect the 1H relaxation behavior markedly, even at relatively high SMP concentrations (15-25%). Comparison of rheological measurements and NMR measurements suggested that the collapse of κ-casein during acidification could contribute to the initial decrease in 17O and 1H relaxation rate in the pH range between 6.6 and 5.5 for 15% SMP and in the pH range between 6.6 and 5.9 for 25% SMP. However, below pH 5.5 the viscosity and 17O and 1H NMR relaxation rates did not correlate, revealing that the aggregation of casein micelles, which increases viscosity below pH 5.5, does not involve major repartitioning of water.     

Occurrence of cystic ovaries in dairy cows in Sweden

The occurrence of cystic ovaries in dairy cows in Sweden was investigated using data on almost 390 000 individuals. Longistic regression analysis was used to assess relationships between cystic ovaries and explanatory variables. Cows of the Swedish Red and White breed (SRB) had twice as many diagnosed cystic ovaries as did Swedish Friesians (SLB), and first-parity cows had half as many cystic ovaries as older cows. The odds for cystic ovaries increased with increasing parity for SRV cows, even after second parity, but not for SLB cows. The diagnosis appeared to be made earlier during lactation in SRB and in high-parity cows. Twin calving in the present lactation and cysts in the previous lactation increased the odds. Cows calving either during months with subsequent risk periods during pasturing or during months with increasing daylight had lower odds for cystic ovaries. The odds increased with increasing milk yield in the present lactation (estimated conditionally on yield in the previous lactation), but decreased with increasing production in the previous lactation (estimated conditionally on yield in the present lactation). In SRB cows, the odds decreased with increasing herd production level.     

Aggression and cortisol levels in three different group housing routines for lactating sows

Background

Lactating sows in Swedish organic piglet production are commonly group-housed with piglets in a multi-suckling pen within 14 days after farrowing. Nursing behaviour may be disturbed when lactating sows are moved to a new environment and mixed with other sows, as they spend more time fighting with other sows and exploring the new surroundings. This can disrupt the inhibitory effect of suckling on ovarian activity and increase the risk of lactational oestrus, making efficient reproductive management difficult. Therefore this study evaluated aggression and levels of the stress hormone cortisol in lactating sows group-housed together with their piglets at one (W1), two (W2) or three (W3) weeks post farrowing.

Results

There was no significant difference (P > 0.05) between the three management routines (W1, W2, W3) regarding number of attacks initiated or received in the mixed group. After mixing, W2 sows had a lower number of shoulder scratches (P < 0.05) than W3 sows. Among the W3 sows, there was a lower (P < 0.01) cortisol concentration in saliva when sows were group housed compared to when they were individually housed. The cortisol response, measured as variation in cortisol concentration in saliva, was also lower (P < 0.05) in group-housed W3 sows compared with W1 sows.For all management routines, sows already living in the new environment (resident sows) initiated more attacks (P < 0.001) and received fewer attacks (P < 0.01) than sows entering the new environment (intruder sows). Overall, multiparous sows initiated more attacks and received fewer attacks than primiparous sows (P <0.001).

Conclusions

Overall, the results suggest that mixing and group housing sows at three weeks post farrowing is less stressful than mixing and group housing sows at one week post farrowing. The results also indicate that parity and whether a sow is a resident or intruder in the group housing environment may have an effect on aggression levels when sows are group-housed.     

Production of trichothecenes and other secondary metabolites by Fusarium culmorum and Fusarium equiseti on common laboratory media and a soil organic matter agar: an ecological interpretation

Fusarium culmorum and F. equiseti were characterized with regard to production of trichothecenes and other secondary metabolites. Results following growth on laboratory media are interpreted with the aim of increasing the understanding of fungal metabolism in the field environment. While trichothecene production was detected for 94 of 102 F. culmorum isolates, only 8 of 57 F. equiseti isolates were positive. Profiles of secondary metabolites were compared by following growth on yeast extract sucrose agar (YES), potato sucrose agar (PSA), and an agar medium, prepared from soil organic matter (SOM), which was included to simulate growth conditions in soil. SOM supported the production of chrysogine by F. culmorum. The two species utilized the media differently. F. culmorumproduced zearalenone (ZEA) on YES, whereas some F. equiseti isolates produced ZEA on PSA. Other F. equiseti isolates produced equisetin. These differences may reflect that F. culmorum depends on a pathogenic life style while F. equiseti has a more saprotrophic mode of existence.     

Effect of medium hydrostatic pressure on the properties of wheat flour main biopolymers

In our work, the effect of medium hydrostatic pressure on the properties of wheat flour's main ingredients, starch and proteins, is presented and discussed. The symbiotic effect of the different constituents via size exclusion chromatography, water binding, gelatinization experiments as well as atomic force microscopy measurements and X-ray diffraction is elucidated. From results of size exclusion chromatography and protein content analysis, prolamin fractions seemed to be most sensitive to pressure. Hydrostatic pressure, however, had a significant influence on the amount of bound water and gelatinization enthalpy, especially at moderate pressures and higher temperatures. In this case, an optimal interaction between macromolecules and water occurs. This was also confirmed by atomic force microscopy images and X-ray diffraction patterns. Amorphous and crystalline regions of starch granules were modified, depending on pressure and temperature. At medium pressure (200 MPa), water was pressed into the starch cavities remaining there, whereas higher pressure (600 MPa) led to complete flattening of the surface. With X-ray diffraction, it was shown that medium pressure had nearly no effect on molecular structure, whereas higher pressure caused thermal-like molecular modifications.     

Genetic and Environmental Correlations Among Female Fertility Traits,and Between the Ability to Show Oestrus and Milk Production in Dairy Cattle

Genetic and environmental correlations were estimated both between the ability to show oestrus and milk production, and among different fertility traits (heat-intensity score, number of days between consecutive inseminations, number of inseminations per service period, interval between calving and first or last insemination, and interval between first and last insemination). Milk production was measured as the average of the energy-corrected milk yield on second and third monthly test days. The number of records were approximately 450000, 350000, 180000 and 75000 in the heifer period, first, second and third lactations, respectively. A linear, trivariate model that included the effects of herd-year, year, month, age and cow's sire was applied. The results indicated that further selection for increased milk production is not expected to deteriorate heat intensity. The number of days between calving and first insemination, the number of inseminations and the heat intensity were complementary, and can be recommended for a selection index for fertility.     

Breed and Management Interaction for Production and Reproduction in Swedish Dairy Cows

The effects of grazing during summer and possible interaction effects between breed and management system on milk production and postpartum reproductive performance were studied in 93 Swedish Red and White (SRB), Swedish Holstein (SLB) and Swedish Jersey (SJB) cows with 214 initiated lactations. The cows were divided into two groups: zero-grazing with tiestalls, or grazing during summer. Effects were studied by mixed-model analysis. The results indicated that grazing (rather than zero-grazing) can reduce the milk yield in the following lactation in SLB cows, whereas it had little effect on the production of SRB cows. Grazing SJB cows produced more milk, but with a significantly lower fat content. Grazing before or during the postpartum period stimulated reproductive performance, indicating a higher conception rate in all breeds and a 13-27-day shorter interval from calving to conception in the SRB and SLB cows, whereas in the limited number of SJB cows, the trend was the converse.     

Milk Production in Swedish Dairy Cows Managed for Calving Intervals of 12 and 15 Months

The effects of calving intervals of 12 and 15 months on milk yield and milk composition were studied in 105 Swedish Red and White (SRB) and 46 Swedish Holstein (SLB) cows with 280 initiated lactations and 165 completed lactations (followed by another calving). The cows were divided into two groups, one early inseminated and the other late inseminated. The cows in the early group were inseminated at first oestrus 50 days after calving, aiming at a conventional 12-month calving interval, and the second group 140 days after calving, aiming at an extended calving interval of 15 months. Effects were studied by mixed-model analysis. Compared with the 12-month groups, total milk yield increased by 15-16% in the extended calving interval groups of both breeds, while fat, protein and lactose contents were slightly lower. The duration of lactation was 55-60 days longer in the 15-month than in the 12-month groups of both breeds. Given the possibility of a longer lactation, primiparous cows generally maintained their production longer than multiparous cows. SLB cows, especially those with a high peak yield, maintained their production longer than SRB cows. Average milk production per day within a calving interval tended to be slightly lower (2-5%) in both breeds when the interval was extended, owing to longer periods with low production and longer dry periods.