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Showing papers in "Journal of Dairy Science in 1968"


Journal ArticleDOI
TL;DR: In this article, an average decline of 3.0 units of digestibility per unit of silica in the dry matter has been found, where W is cell walls, SiO 2 is silica on a dry matter basis, and L is the lignin content of acid-detergent fiber.

215 citations


Journal ArticleDOI
TL;DR: Culture filtrates of Lactobacillus lactis and LactOBacillus bulgaricus were observed to contain material inhibitory against Staphylococcus aureus, and the inhibitory factor was identified as hydrogen peroxide.

213 citations


Journal ArticleDOI
TL;DR: Losses in milk yield due to delayed breeding were determined from 4,910 complete lactations of Holsteins in the North Carolina Institutional Breeding Association and a calving interval of 13 months for first calvers and 12 months for second and later calvers was suggested for attaining maximum production.

185 citations


Journal ArticleDOI

184 citations


Journal ArticleDOI
TL;DR: In this article, it was concluded that micellar and serum casein do not form an equilibrium system controlled by the solubilities of the various caseins, and that the degree of polymerization of temperature-sensitive casein components (mostly β -casein) is one of the major factors controlling the proportion of casein present in mousellar form.

174 citations


Journal ArticleDOI
TL;DR: The primary and secondary stages of the heat denaturation of bovine β-lactoglobulin A have been examined using starch gel electrophoresis and sedimentation velocity techniques as discussed by the authors.

166 citations


Journal ArticleDOI
TL;DR: Since entry of ammonia into cells appears to be prerequisite for its toxicity, penetration of cell membranes by ammonia has been studied under a variety of circumstances, and some general theories regarding the behavior of ammonia in biological systems which are pertinent to problems of intoxication arising from incorporation of non-protein nitrogen (NPN) in animal diets are formulated.

128 citations



Journal ArticleDOI
TL;DR: An electronic recording microbalance was incorporated into a gravimetric adaption apparatus for precise study of adsorption and desorption phenomena on dehydrated dairy products as mentioned in this paper.

112 citations


Journal ArticleDOI
TL;DR: In this paper, a fermentation balance equation was used to estimate the extent of fermentation of rations fed at or near voluntary intake to lactating dairy cows, and the assumptions involved in these computations and the implications of the results obtained on efficiency of fermentation and feed efficiency for ruminants were discussed.

111 citations



Journal ArticleDOI
TL;DR: In this article, the authors used gas entrainment, on-column trapping, and a modified GLC technique to determine the concentration of diacetyl in both heated and raw milk, while the amount in the heated milk was 38 ppb.


Journal ArticleDOI
TL;DR: A series of theoretical estimates of the efficiencies of metabolic and physiological processes which can be related to nutritional energetic measurements is presented in the hope that others also might find them useful.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the nature and extent of protein aggregation produced by heating whey and skimmilk systems and found that protein aggregation in heated whey systems is a multi-reaction process involving denaturation of whey proteins through thiol-disulfide group, hydrogen and hydrophobic bond reactions.

Journal ArticleDOI
TL;DR: Water vapor is absorbed by milk powder at sites dependent upon the relative pressure, P/Po, of the atmosphere to which the powder is exposed as discussed by the authors, and as the P/P progresses toward 0.5, lactose becomes more active in water binding.

Journal ArticleDOI
TL;DR: In this article, the effects of gums with skimmilk and with purified proteins were investigated using polyacrylamide gel (PAG) electrophoresis and centrifugation.

Journal ArticleDOI
TL;DR: Results of feeding a hydroxy methionine analog as a preventative for bovine ketosis indicated a significant stimulatory effect on milk production.

Journal ArticleDOI
TL;DR: A serological test for staphylococcal enterotoxin, using a microslide gel diffusion technique, was employed to examine 4.07million pounds of cheese suspected of containing staphilic enteroxin A.

Journal ArticleDOI
TL;DR: The numbers of bacteria, estimated by colony counts, in samples of rumen digesta obtained from different positions in the rumen were determined at 1, 2.0, 5.5, and 10 hours after feeding four heifers at 12 hour intervals at the maintenance level of intake.

Journal ArticleDOI
TL;DR: Moisture levels and storage temperatures influenced growth and survival, and salmonellae added to nonfat dried milk were quite resistant to dry heat.


Journal ArticleDOI
TL;DR: In this paper, the authors studied the genetic aspects of gross feed efficiency of milk production, defined as the ratio kilogram of fat-corrected milk yield per therm of estimated net energy consumed.

Journal ArticleDOI
TL;DR: In this paper, the casein micelles from skimmilk were compared using osmium tetroxide, formaldehyde and, for the first time, glutaraldehyde, and a rapid procedure coupled with a dispersion method was developed.

Journal ArticleDOI
TL;DR: The intent in this presentation is to discuss, as quantitatively as possible, the pathways of the major N fractions through the ruminant body and interactions with other feed components in the rumen.

Journal ArticleDOI
TL;DR: In this article, a procedure for the preparation of pure κ-casein by Sephadex gel filtration is described, which is particularly suitable for preparing pure casein in good yield from small quantities of whole casein, but larger amounts of casein are readily prepared.

Journal ArticleDOI
TL;DR: A daily increment of somewhat less than 7.0g concentrate per unit of metabolic body size, in combination with a feeding frequency of at least two times per day, was necessary to avoid off feed in yearling dairy heifers.


Journal ArticleDOI
TL;DR: Spermatozoa recovered from the caput epididymides of four bulls were immotile, whereas sperm from the caudal sperm were used to inseminate 100 cows, and 69% did not return for reinsemination in 60 to 90 days.

Journal ArticleDOI
TL;DR: Corn harvested for silage at 30, 36, and 44% dry matter was treated with 0 or 0.5% urea at ensiling time and lost more dry matter than control silages, and milk yields were not affected by urea-treatment of silage, but were decreased.