Activation of Vitamin D3 in Bovine Mastitis Caused by Streptococcus uberis

Inflamed mammary tissue of three cows infected with Streptococcus uberis was found to have higher concentrations of 1α-hydroxylase than un-inflamed control mammary glands. Increased levels of 1α−hydroxylase resulted in increased production of 1,25-dihydroxyvitamin D3. Therefore, vitamin D3 may have a role in the inflammation and resolution of bovine mastitis

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

Effect of Feeding Ethanol By-Products on Performance and Marbling Deposition in Steers Fed High-Concentrate or High-Forage Diets

Research on the effect of dietary ethanol by-products on beef quality has been limited. Some Universities have reported a decrease in marbling due to distillers grains inclusion, while others have not. It is unclear why marbling deposition may be decreased when increasing amounts of distillers grains are fed; however, decreased starch availability, increased vitamin A and D, and the high oil content in ethanol by-products may contribute. In contrast, distillers grains can increase unsaturated fatty acid content of beef, thus increasing healthfulness. Our objective was to measure the effect of wet distillers grains (0, 20, or 40 % of the diet) on growth, feed intake, and marbling deposition and to determine what may be responsible for decreased marbling. Average daily gain and feed intake did not differ between wet distillers grains treatments, but cattle fed distillers grains were more efficient. Marbling score decreased in high-concentrate-fed steers as WDG concentration was increased, but increased in high-foragefed steers from the 0 to 20% WDG inclusion rate and then decreased from the 20 to 40% WDG inclusion rate. Backfat thickness decreased in high-concentrate-fed steers as WDG concentration increased but increased in high-forage-fed steers from the 0 to 20% WDG inclusion rate and then decreased from the 20 to 40% WDG inclusion rate. Cattle fed distillers grains had lower plasma total vitamin A and plasma vitamin D. Retinol, however, was positively related to marbling and vitamin D was negatively related to marbling. Polyunsaturated fatty acids, which can enhance the healthfulness of beef, were increased by feeding wet distillers grains, but were related to decreased marbling

Redesigning Pork by Type and Amount of Dietary Fat for Bet- ter Human Nutrition

An experiment to modify pork by supplementa- tion of dietary lipids yielded the following conclusions: 1) Supplementation of pig diets with high levels of lipids did improve feed conversion without affecting other growth performance characteristics. 2) Feeding of choice white grease increased the content of monounsaturated fatty acids in skeletal muscle and adipose tissues of pigs. 3) Feeding soybean oil, increased the content of polyunsatu- rated fatty acids in skeletal muscle and adipose tissues of pigs

Method of converting cholesterol in food to coprostanol

Cholesterol reductase was discovered in certain green plant parts. The enzyme is known to be present in several bacteria that commonly inhabit the digestive tract of animals. Eubacteria species A.T.C.C. 21408 is one such cholesterol reductase-containing bacterium. It is concentrated from a homogenate, preferably of leaves of plants or from bacteria or other organisms to provide a cell-free, cholesterol reductase-enriched preparation that can be used to decrease cholesterol content of food substances

Plane of Nutrition Affects Plasma Ghrelin Concentrations in Neonatal Calves

Investigating different planes of nutrition on appetiterelated hormones could provide knowledge into the role of these hormones on growth performance in neonatal calves. The objective of the current study was to investigate the effects of feeding rates on ghrelin in plasma from preruminant calves. Treatments (n = 8 per treatment) were designed to achieve three targeted daily rates of gain (No Growth = 0.0 kg, Low Growth = 0.55 kg, or High Growth = 1.2 kg) in live weight over a 7-wk period. All calves were fed a 30% crude protein, 20% fat, all-milk protein milk replacer reconstituted to 14% dry matter. Daily growth rates for No, Low, and High Growth calves were different (P\u3c 0.001) throughout the experimental period and averaged 0.11 ± 0.02 kg, 0.58 ± 0.02 and 1.16 ± 0.04 kg, respectively. Fasting ghrelin active concentration was higher (P \u3c 0.0001) in the No Growth calves over the 7-wk period in comparison to the Low and High growth calves. Circulating concentrations of ghrelin in neonates fed different planes are similar to responses of adult humans to feed intake. These results indicate an inverse relationship of ghrelin active concentration with respect to plane of nutrition and growth rate in neonates

Parturition Invokes Changes in Peripheral Blood Mononuclear Cell Populations in Holstein Dairy Cows Naturally Infected with Mycobacterium Avium Subsp. Paratuberculosis

Twenty-one multiparous and two primiparous Holstein cows were grouped according to infection status with Mycobacterium avium subsp. paratuberculosis (MAP), the causative microorganism for Johne’s disease (JD). The effect of parturition and infection on the percentages of CD4 + , CD8 + , and T-cells, B-cells, and monocytes in the peripheral blood were monitored. The data suggest that changes in the percentages of lymphocyte subsets and monocytes are modulated by both infection status and the periparturient period

Osteopontin Expression in Periparturient Dairy Cows Naturally Infected with Mycobacterium Avium Subsp. Paratuberculosis

Twenty-five multiparous Holstein cows were grouped according to infection status with Mycobacterium avium subsp. paratuberculosis (MAP), the causative microorganism of Johne’s disease (JD). Osteopontin (Opn) was characterized at both the level of gene and protein expression. Results of this study indicate that in dairy cows, expression of Opn is modulated by natural infection with MAP and by the periparturient period

1,25-Dihydroxyvitamin D3 Enhances Bovine Mammary Epithelial Innate Immune Responses

Bovine mammary epithelial cells that were treated with bacterial lipopolysaccharide and 1,25-dihydroxyvitamin D3 showed an increase in the expression of the genes for inducible nitric oxide synthase (iNOS) and S100 calcium binding protein A12 (S100 A12). iNOS and S100 A12 are part of the innate immune response and expressed in the mammary gland during mastitis. Production of 1,25- dihydroxyvitamin D3 in the mammary gland during mastitis, then, may be an important component of the innate immune response

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