Regulation of Periparturient Milk Composition in Jersey Cattle

The composition of milk from dairy cows varies more in the colostral period than in other periods of lactation. The objective of this study was to determine which factors influence milk composition of Jersey cows during the colostral period. Composite milk samples were collected from 21 lactating Jersey cows of the Iowa State University Teaching Herd between February and July at 0, 12, 24, 30, 38, 46, 54, 62, 80, and 88 hours postpartum. The milk samples were analyzed for total fat, lactose, and protein content by infrared spectroscopy, for total protein nitrogen, non-casein nitrogen, and non-protein nitrogen content by Kjeldahl analyses, and for αS1–casein, β-casein, κ-casein, αS2-casein, α-lactalbumin, and β–lactoglobulin concentrations by reversed-phase HPLC. Milk composition changed during the first 4 days after parturition and was influenced by calving season, length of gestation, and parity; and all had significant interactions with time postpartum (all P \u3c 0.01). Colostrum matured to normal milk in the first two days after parturition. The maturation of colostrum was associated with an increase in lactose content and a decrease in protein content, in particular of whey proteins other than α–lactalbumin. The colostrum of cows that calved between February and April had a lower lactose and a greater protein content, in particular of whey proteins other than α–lactalbumin and β–lactoglobulin, than did colostrum of cows that calved in May and June. The colostrum of multiparous cows was higher in protein content than was the colostrum of heifers because of higher concentrations of whey proteins. During the colostral period, milk of cows that calved before the predicted calving date had greater protein concentrations than did milk from cows that calved at or after the predicted calving date, which was the result of higher concentrations of whey proteins other than α–lactalbumin and β–lactoglobulin. We conclude that time postpartum, calving season, length of gestation, and parity affect the composition of milk in the early secretory period in lactating Jersey cows

Changes in Milk Protein and Amino Acid Composition of Dairy Cows in Response to Fatty Liver and Intravenous Glucagon

Intravenous glucagon cures fatty liver by improving glucose bioavailability in early lactation. Amino acids, which would be otherwise used for milk protein synthesis, are metabolized to glucose. The objective of this study was to examine whether intravenous glucagon and fatty liver change milk protein and amino acid composition in dairy cows. Multiparous Holstein cows (n=25) were designated as either normal or susceptible to fatty liver and ketosis as based on the ratio of liver triacylglycerol to glycogen being smaller or greater than 2.0 at d 6 postpartum. Cows susceptible to fatty liver were subjected for 3 weeks to a protocol consisting of feed restriction and dietary 1,3- butanediol beginning at d 14 postpartum, which induced fatty liver and ketosis. Normal cows and cows with fatty liver were infused with glucagon for 14 d at 0 or 10 mg/d beginning at d 21 postpartum. Composite milk samples were obtained at d 20, 22, 34, and 36 postpartum and analyzed for milk protein and amino acid composition. Fatty liver decreased milk yield but had little effect on milk protein and amino acid composition except for increasing the proportion of glycosylated κ-casein. Intravenous glucagon decreased total milk protein concentrations and the proportion of α–lactalbumin and increased the proportion of glycosylated κ-casein, total κ-casein, and αS2-casein. Intravenous glucagon had little effect on milk amino acid composition. Our results suggest that milk protein and amino acid composition are under tight concomitant hormonal control and are affected little by changes in amino acid availability and/or insulin to glucagon ratio

Genetic Manipulation of Adipose Cells to Improve Fatty Acid Composition of Meat

The purpose of this study is to modify adipose cells genetically in culture to produce cells that contain less saturated fat. To accomplish this objective, a fatty acid desaturase gene from castor beans will be transferred into adipose cells. Using cultured liver cells as a test system, the gene was successfully transferred into 12 different cultures of liver cells. We are currently studying the production of the corresponding RNA from the incorporated gene and the fatty acid composition of the transformed cells. Our next goal is to conduct similar activities using cultured adipose cells. Saturated fatty acids make up 40 to 55% of the total fat associated with meat. It has been demonstrated in animal and human studies that dietary saturated fatty acids (excluding C18:0) are hypercholesterolemic when compared with polyunsaturated fatty acids. Therefore, nutritional scientists must seek with urgency nutritional, managerial, and genetic protocols for decreasing the fat content and the proportion of saturated fatty acids in animal-derived foods

Milk Protein Genotypes Explain Variation of Milk Protein Composition

The data demonstrate that cows with the genotypes κ- casein BB and β-lactoglobulin BB produce milk with a protein composition that is favorable for increased cheese yield. For proportions of αS1-casein, κ-casein, and β-lactoglobulin in total milk protein, κ-casein and β-lactoglobulin genotypes explained more than 50 and 25% of the heritability and repeatability estimates, respectively, and more than 14% of the phenotypic variance. Diet had only a minimal effect on milk protein composition. In conclusion, increasing cheese yield through modification of milk protein composition can be achieved most rapidly by selection for cows with κ-casein BB and β-lactoglobulin BB genotypes

Texture of Butters Made from Milks Differing in Indices of Atherogenicity

The current study examined whether the phenotypic variation in milk fatty acid composition among cows fed the same diet was sufficient to produce butter with different textural properties. Butter samples from cows with a more unsaturated milk fatty acid composition had a lower index of atherogenicity and were more spreadable, softer, and less adhesive than were butter samples from cows with a more saturated milk fatty acid composition. Thus, selection of cows for milk fatty acid composition short-term by segregation and long-term by breeding programs can be used to produce butter that is more healthful and has a more favorable texture

Convergence towards a European strategic culture? A constructivist framework for explaining changing norms.

The article contributes to the debate about the emergence of a European strategic culture to underpin a European Security and Defence Policy. Noting both conceptual and empirical weaknesses in the literature, the article disaggregates the concept of strategic culture and focuses on four types of norms concerning the means and ends for the use of force. The study argues that national strategic cultures are less resistant to change than commonly thought and that they have been subject to three types of learning pressures since 1989: changing threat perceptions, institutional socialization, and mediatized crisis learning. The combined effect of these mechanisms would be a process of convergence with regard to strategic norms prevalent in current EU countries. If the outlined hypotheses can be substantiated by further research the implications for ESDP are positive, especially if the EU acts cautiously in those cases which involve norms that are not yet sufficiently shared across countries

Unique thermodynamic relationships for ΔfHo and ΔfGo for crystalline inorganic salts. I, Predicting the possible existence and synthesis of Na2SO2 and Na2SeO2

The concept that equates oxidation and pressure has been successfully utilized in explaining the structural changes observed in the M2S subnets of M2SOx (x = 3, 4) compounds (M = Na, K) when compared with the structures (room- and high-pressure phases) of their parent M2S 'alloy' [Martinez-Cruz et al. (1994), J. Solid State Chem. 110, 397-398; Vegas (2000), Crystallogr. Rev. 7, 189-286; Vegas et al. (2002), Solid State Sci. 4, 1077-1081]. These structural changes suggest that if M2SO2 would exist, its cation array might well have an anti-CaF2 structure. On the other hand, in an analysis of the existing thermodynamic data for M2S, M2SO3 and M2SO4 we have identified, and report, a series of unique linear relationships between the known Delta H-f(o) and Delta(f)G(o) values of the alkali metal (M) sulfide (x = 0) and their oxyanion salts M2SOx (x = 3 and 4), and the similarly between M2S2 disulfide (x = 0) and disulfur oxyanion salts M2S2Ox (x = 3, 4, 5, 6 and 7) and the number of O atoms in their anions x. These linear relationships appear to be unique to sulfur compounds and their inherent simplicity permits us to interpolate thermochemical data (Delta H-f(o)) for as yet unprepared compounds, M2SO (x = 1) and M2SO2 (x = 2). The excellent linearity indicates the reliability of the interpolated data. Making use of the volume-based thermodynamics, VBT [Jenkins et al. (1999), Inorg. Chem. 38, 3609-3620], the values of the absolute entropies were estimated and from them, the standard Delta S-f(o) values, and then the Delta(f)G(o) values of the salts. A tentative proposal is made for the synthesis of Na2SO2 which involves bubbling SO2 through a solution of sodium in liquid ammonia. For this attractive thermodynamic route, we estimate Delta G(o) to be approximately -500 kJ mol(-1). However, examination of the stability of Na2SO2 raises doubts and Na2SeO2 emerges as a more attractive target material. Its synthesis is likely to be easier and it is stable to disproportionation into Na2S and Na2SeO4. Like Na2SO2, this compound is predicted to have an anti-CaF2 Na2Se subnet

Coccidioidomycosis as a Common Cause of Community-acquired Pneumonia

The early manifestations of coccidioidomycosis (valley fever) are similar to those of other causes of community-acquired pneumonia (CAP). Without specific etiologic testing, the true frequency of valley fever may be underestimated by public health statistics. Therefore, we conducted a prospective observational study of adults with recent onset of a lower respiratory tract syndrome. Valley fever was serologically confirmed in 16 (29%) of 55 persons (95% confidence interval 16%–44%). Antimicrobial medications were used in 81% of persons with valley fever. Symptomatic differences at the time of enrollment had insufficient predictive value for valley fever to guide clinicians without specific laboratory tests. Thus, valley fever is a common cause of CAP after exposure in a disease-endemic region. If CAP develops in persons who travel or reside in Coccidioides-endemic regions, diagnostic evaluation should routinely include laboratory evaluation for this organism