Showing papers in "Journal of Dairy Science in 1993"

TL;DR: The mechanism of how lipids interfere with ruminal fermentation is a complex model involving partitioning of lipid into the microbial cell membrane, potency of the lipid to disrupt membrane and cellular function, physical attachment of microbial cells to plant surfaces, and expression and activity of microbial hydrolytic enzymes.

TL;DR: The most significant changes in milk fat quality relate to rheological (melting) properties, which influence numerous aspects of character and quality of manufactured dairy products.

TL;DR: Research to determine methods to reduce fatty acid delivery to the liver or to enhance hepatic export of very low density lipoprotein near calving is warranted because of increased fatty acid uptake by the liver, fatty acid esterification, and triglyceride storage.

TL;DR: To optimize performance, oxidative stress in high producing cows must be controlled by supplying all known antioxidant nutrients and by minimizing effects of substances that stimulate reactive oxygen metabolites.

TL;DR: The techniques reported in this paper were developed to facilitate the study of the kinetics of forage digestion in vitro by measuring gas production by a modified NDF method that allows determination of extent of digestion at the end of an incubation in which gas production has been monitored.

TL;DR: Bovine embryos become more resistant to adverse effects of maternal heat stress as pregnancy progresses; substantial resistance develops by d 3.

TL;DR: Dietary fat decreased de novo fatty acid synthesis and basal glycerol release in adipose tissue and tended to increase simultaneously beta-adrenergic lipolytic responses to increased membrane fluidity and a trend toward insulin resistance, which was more marked with saturated fatty acids, occurred in adipOSE tissue.

TL;DR: In this article, an important role is suggested for colloidal Ca phosphate in buffering during the acidification of milk and cheese, which increases the aggregation of renneted micelles.

TL;DR: Correlations between reproductive traits and measures of milk yield indicate that higher yield is associated phenotypically and genetically with reduced reproductive performance in lactating cows, and the extent to which negative energy balance alters hypothalamic secretion of GnRH and its effect on gonadotropin secretion and, therefore, ovarian secretion of progesterone is unknown.

TL;DR: Proteolytic events taking place during cheese ripening are described, and the characteristics of various proteolytic systems involved are reviewed in this article, where some emphasis is placed on the proteolyptic enzymes from starter bacteria because these, in particular, have been subjects of recent and current research.

TL;DR: New insights on the biological mechanisms of absorption and transport of lipid in ruminants are reviewed, especially the modern concepts and analytical methods used in studies on structural properties and intravascular and tissue metabolism of lipoproteins and their factors of variation are reviewed.

TL;DR: Diurnal variations of serum and milk urea should be considered if urea is to be used as an indicator of nutritional status, and time of sampling versus time of feeding is crucial.

TL;DR: The means by which lactic acid bacteria defend against low intracellular pH are presented, and particular attention is devoted to the proton-translocating ATPase, an enzyme that is largely responsible for pH homeostasis in fermentative lactic Acid bacteria.

TL;DR: In this article, path analysis and multiple logistic regression with an extrabinomial variation error term (to account for herd) were used to model seven postpartum clinical disorders of dairy cows and factors related to the calf.

TL;DR: Considerable variation existed among cultures in their ability to grow in the presence of bile, to deconjugate sodium taurocholate, and to assimilate cholesterol, however, statistical analyses revealed no significant correlations.

TL;DR: The immune system is primarily responsible for defense against invading organisms and the effects of several mycotoxins on the immune responses have been investigated; however, most data concern laboratory animals.

TL;DR: In this article, the authors present some of the current knowledge on the biological action of four diverse classes of mycotoxins (aflatoxin B1, tricothecenes, zearalenone, and fumonisin B1) with particular emphasis on mechanisms of action.

TL;DR: Detailed observations, using intact and ruminally cannulated cows, suggest a behavioral need for the cow to rest and to ruminate on her left side in cows reared in group housing compared with isolated cows.

TL;DR: In this paper, anhydrous milk fat was microencapped in whey protein concentrates and a wheyprotein isolate by spray drying, and the effects of microencapsulating agent type and concentration (10 to 30% wt/wt) and of fat load (25 to 75% Wt/Wt) on the micro-encapsulation yield and efficiency were determined.

TL;DR: No significant relationships of body condition score to the incidences of pyometra, metritis, retained placenta, cystic ovarian disease, AI per conception, days to first AI, or dystocia existed in this herd.

TL;DR: Extensive differences in ruminal degradation kinetics existed between perennial legume and grass species and maturities, making categorization of degradation characteristics of legumes and grasses difficult.

TL;DR: This review presents some of the current knowledge on the biological action of four diverse classes of mycotoxins--aflatoxin B1, tricothecenes, zearalenone, and fumonisin B1--with particular emphasis on mechanisms of action.

TL;DR: Subcutaneous injections of vitamin E approximately 10 and 5 d prior to calving successfully elevated neutrophil alpha-tocopherol concentrations during the periparturient period and negated the suppressed intracellular kill of bacteria by neutrophils that is commonly observed at calving.

TL;DR: Prepartum propylene glycol administration reduced hepatic triglyceride accumulation by 32 and 42% at 1 and 21 d postpartum, respectively, and prepartum plasma BHBA was reduced during propylene Glycol administration.

TL;DR: Short peptides derived from milk proteins with physiological activities can all nevertheless be synthesized and used either as food additives or in pharmacology, if, in the future, some of the active peptides cannot be characterized in vivo.

TL;DR: Research of the past 12 yr related to dairy replacements is summarized and incorporates those findings into possible scenarios for future dairy calf and heifer management systems.

TL;DR: Lactobacillus bulgaricus cells were entrapped in beads of calcium alginate and evaluated for their ability to survive freezing processes, finding that cells survived freezing (without agitation) in ice milk mix much better than in distilled water, and moreEntrapped cells survived than did cells that were not entrapping.

TL;DR: The immunostimulatory action of carotenoids may be translated into improved health, including mammary and reproductive health in dairy cattle, and more studies are needed to establish fully the beneficial effects of supplementation of different carOTenoids on the health of dairy cattle.

TL;DR: The clinical interpretation of serum urea N on conception rate is evaluated using Bayes theorem from two approaches (dichotomization vs. continuous) and test information resulting from dichotomization of serum Urea N into high and low categories is compared with likelihood ratio approaches allowing a continuous measure.