Showing papers in "Journal of Dairy Science in 1986"

TL;DR: In this article, chemical constraints that may be responsible for the decrease in fiber digestion are explored, and a major factor appears to be rumen pH, to approximately 6.5 or 5.0, which results in depressed growth rates and decreased fibrolytic organisms.

TL;DR: Bacterial protein synthesis was reduced 34 to 69% when initial pH was 6.0, but these reductions were greater than decreases in carbohydrate utilization, increases in lactate, and associated decreases in adenosine 5'-triphosphate production.

TL;DR: In this article, an efficient algorithm for computing restricted maximum likelihood estimates of variance components in a class of models is described, characterized by effects to be absorbed, which are nested within herds, other fixed effects, random sire effects, and a random residual.

TL;DR: Somatic cell count linear score of 5 (283,000) appears to be a good choice of threshold for mastitis control applications and a greater understanding of the nonbacteriological factors affecting somatic cell count is needed so that relative thresholds could be used to improve the clarity of somaticcell count interpretation.

TL;DR: The mechanism of calcium and phosphorus homeostasis in dairy cows is described to provide a clearer understanding of the rationale behind current management and supplementation practices and the need to keep prepartum dietary calcium intake at less than or equal to 50 g/d to minimize the incidence of milk fever is addressed.

TL;DR: Results are consistent with growth hormone functioning as a homeorhetic control of nutrient partitioning as well as the galactopoeitic action of growth hormone, which may be partly attributable to its effects on responsiveness of adipose tissue to a lipolytic stimulus.

TL;DR: Regulation of intake in ruminants is primarily a function of physical fill for diets that are energetically dilute and less digestible, such as high-forage diets; but intake becomes primarily afunction of metabolic control for diets That are ener getically dense and highly digestable, suchAs high-concentrate diets.

TL;DR: Measurement of hormone concentrations in the plasma of pregnant animals shows considerable differences among species in the pattern of secretion of lactogenic hormones to bring about mammary development, including species differences in minimal hormonal requirements for lactogenesis.

TL;DR: In this article, six Holstein cows were fed prebloom alfalfa hay in long, chopped, and pelleted form (60:40 hay:grain ratio) in a replicated 3×3 Latin square design (21-d periods) conducted in early (wk 3 to 11) and middle (wk 20 to 32) lactation and during the dry period to attain three feed intakes for determination of digesta kinetics.

TL;DR: It is indicated that the surface on which cows were observed had a profound effect on sexual behavior; however, postpartum interval, season of year, and milk yield were of minor importance.

TL;DR: Present evidence favors a recommendation for treatment of all cows at the time of drying off and a shortcoming of present therapy regimens for the dry period is that they provide little or no protective effect against new infection prepartum.

TL;DR: Based on desirable fat and casein contents of milk for cheese production, it would be advantageous to select for cows bearing κ-casein BB and β-lactoglobulin BB phenotypes.

TL;DR: Mean particle length did not affect actual milk or 4% fat-corrected milk production, and apparent digestibility of dietary constituents and rate of passage of hay and concentrate was not influenced by forage intake or physical form.

TL;DR: Results indicate that although the recovery of fiber among bermuda forages was biased in favor of those having lower fiber content, fiber recovery for sorghum forage was unbiased with a mean of 96% and low standard error (1.5).

TL;DR: A summary of in vivo estimates of the amount of dietary protein from individual feedstuffs that escapes microbial degradation in the rumen is presented and strategies for using protected proteins in dairy cattle diets are discussed.

TL;DR: In this article, the effect of pH and digesta flow rates on fermentation of a 65% grain, 35% forage ration by rumen microorganisms was evaluated in continuous culture fermentations.

TL;DR: In this paper, the responses of ruminal microbes to long-chain fatty acids in forms of free acids, calcium salts, or triglycerides were measured in trials with rumen cannulated heifers.

TL;DR: Feeding deoxynivalenol-contaminated diets for 5 d did not alter feed intake or milk production nor were the milk concentrations of calcium, phosphorus, sodium, potassium, magnesium, or nitrogen altered.

TL;DR: In this article, the minimum ammonia required for maximal digestion was a function of the rumen fermentability of the diet or feed, and the equation: minimum ammonia concentration (mg/dl) =.452 fermentability % - 15.71, accounted for 50% of the variation in minimum ammonia requirements.

TL;DR: A method for cooling dairy cattle based on repeated wetting to attain maximal water trapping in the coat, followed by its rapid evaporation by using forced ventilation has been examined.

TL;DR: Three approaches to constructing and solving sets of equations of large order are discussed and compared on the basis of number of data elements that must be processed by a computer program during a round of iteration of the solution phase.

TL;DR: Effects of days carried calf, days dry, and weight of first calf heifers were studied using records of Holstein cows processed at the Northeast Dairy Records Processing Laboratory and Calculated F values showed greater significance for days dry than age-month of freshening.

TL;DR: Calves that died of infectious disease during the first 14 wk of life had significantly lower serum total protein concentrations than those that lived, and heritability of serum protein concentration in calves was .02 +/- .03.

TL;DR: Treatment with exogenous somatotropin around puberty enhances the growth rate of mammary parenchymal tissue and additional studies are required to examine whether this enhanced mammary development will increase milk yield during subsequent lactations.

TL;DR: In this article, a total of 31 Holstein cows were selected for their phenotypes for β -casein, κ-casein and κ -lactoglobulin and compared with other phenotypes of the respective proteins under study.

TL;DR: In this paper, the authors evaluated premilking teat disinfectants, premilk teat dipping procedures, and types of paper towels to determine their effects on bacterial counts in milk and on teats.

TL;DR: Resting salivation rate and volume produced while resting were greater at wk 8 than wk 4 of lactation even when corrected to constant dry matter intake, indicating that adaptation to diet postpartum involved increased basal resting salivation rates.

TL;DR: This general review attempts to capture the interest of nonspecialists, especially those whose main interest is the dairy cow, in the extraordinary diversity of milk fats synthesized and secreted by different mammalian species.

TL;DR: In this paper, the authors collected milk samples from 31 Holstein cows of different phenotypes for β-casein, κ-caseins, and β-lactoglobulin were collected monthly over the entire lactation and analyzed for total solids, fat, protein, casein fractions, lactose, urea, citric acid, somatic cell count and pH.

TL;DR: In this article, the authors compared vat versus high temperature, short time, and ultra-high temperature heating systems and found that yogurt firmness ranged from 90 to 104 force for vat treatments, 74 to 96 force for high temperature and short time treatments, and 47 to 65 force for ultra high temperature treatments.