scholarly journals THE RATE OF GROWTH OF THE DAIRY COW

1923 ◽  
Vol 5 (4) ◽  
pp. 445-449 ◽  
Author(s):  
Samuel Brody ◽  
Arthur C. Ragsdale ◽  
Charles W. Turner
Keyword(s):  
Chemical Reaction ◽  
Dairy Cow ◽  
Rate Of Growth ◽  
Entire Duration

An extensive amount of data is presented on the growth in weight of the dairy cow from 2 to 17 years of age, covering practically the entire duration of life. The data show that after the age of 2 years the rate of growth declines in a non-cyclic manner. The course of decline in growth follows the course of decline of a monomolecular chemical reaction; that is, the percentage decline in growth with age is constant.

scholarly journals THE RATE OF GROWTH OF THE DAIRY COW

1923 ◽  
Vol 6 (1) ◽  
pp. 21-30 ◽  
Author(s):  
Samuel Brody ◽  
Arthur C. Ragsdale ◽  
Charles W. Turner
Keyword(s):  
Body Weight ◽  
Chemical Reaction ◽  
Dairy Cow ◽  
Good Measure ◽  
Milk Secretion ◽  
Velocity Constant ◽  
Rate Of Growth ◽  
Maximum Body

It is shown that from 2 years, the age when milk secretion usually begins, to 9 years, the age of maximum body weight, the increase of milk secretion with age follows the course of growth in body weight— both can be accurately represented by the equation of a monomolecular chemical reaction having a velocity constant of approximately the same numerical value. While increase in milk secretion and increase in body weight with age follow the same course, it is shown that increasing body weight contributes only about 20 per cent to increasing milk secretion with age. The fact that milk secretion and body weight follow the same course, even though they are largely independent of each other indicates that increase in body weight is a good measure of growth of the dairy cow; this fact also shows that the increase of milk secretion with age may be used as a measure of growth. The fact that milk secretion, like body weight, follows the course of a chemical reaction, adds further support to the theory that growth is limited by a chemical reaction.

scholarly journals THE RATE OF GROWTH OF THE DAIRY COW

1921 ◽  
Vol 3 (5) ◽  
pp. 623-633 ◽  
Author(s):  
Samuel Brody ◽  
Arthur C. Ragsdale
Keyword(s):  
Dairy Cow ◽  
Growth Period ◽  
Holstein Cows ◽  
Rate Of Growth ◽  
Retarding Effect ◽  
Monomolecular Reaction ◽  
Pregnancy And Lactation

The growth period of the Jersey and Holstein cows is made up of at least three cycles, two extrauterine cycles with maxima at about 5 and 20 months of age, and one intrauterine cycle, the maximum of which has not yet been determined. The equation of an autocatalytic monomolecular reaction was found to give very good results when applied to the cycle having its maximum at about 5 months of age. The values obtained from this equation when applied to the cycle having the maximum at about 20 months of age were higher than the observed values probably due to the retarding effect of pregnancy and lactation on growth.

scholarly journals THE RATE OF GROWTH OF THE DAIRY COW

1924 ◽  
Vol 6 (3) ◽  
pp. 329-336
Author(s):  
Samuel Brody ◽  
Arthur C. Ragsdale
Keyword(s):  
Dairy Cow ◽  
Chemical Process ◽  
Exponential Law ◽  
Rate Of Growth ◽  
Linear Dimensions ◽  
Constant Rate ◽  
The Law ◽  
The Given ◽  
Cyclic Phenomena ◽  
Constant Percentage

Barring fluctuations due to the cyclic phenomena, the extrauterine course of growth in linear dimensions and in weight of the dairy cow follows an exponential law having the same form as the law representing the course of monomolecular change in chemistry. This suggests the interpretation that the general course of growth is limited by a monomolecular chemical process, and that the cyclic phenomena are due to subsidiary processes in the fundamentally exponential course of growth. The fact that growth follows or tends to follow an exponential course may be stated more simply as follows: if the unit of time is taken sufficiently large so that fluctuations due to the cyclic phenomena are balanced or eliminated, then the amount of growth made during the given unit of time at any age tends to be a constant percentage of the growth made during the preceding unit of time. Thus, the growth in height at withers made during any year is about 34 per cent of the growth made during the preceding year. Similarly the growth in weight made during any year is about 56 per cent of the growth in weight made during the preceding year. This is in accordance with expectations if it is assumed that each animal begins life with a definite endowment of limiting substance necessary for the process of growth, and that this endowment is used up at a constant rate (or percentage) of itself.

scholarly journals THE RATE OF OVULATION IN THE DOMESTIC FOWL DURING THE PULLET YEAR

1921 ◽  
Vol 3 (4) ◽  
pp. 431-437 ◽  
Author(s):  
Samuel Brody
Keyword(s):  
Chemical Reaction ◽  
Domestic Fowl ◽  
Autocatalytic Reaction ◽  
Limiting Factor ◽  
Rate Of Growth

The rate of ovulation of the domestic fowl may be expressed by the equation of an autocatalytic chemical reaction. This is not surprising in view of the fact that the rate of growth may also be expressed by such an equation, and that the rate of ovulation is probably an index of the growth of the eggs. This brings the phenomenon of ovulation in the hen under the general subject of growth, and substantiates the generality and the probability of the hypothesis that growth, or at any rate the limiting factor of growth, is an autocatalytic reaction.

scholarly journals Wagner-Vengrenovich Distribution

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Bohdan V. Ivanskii ◽  
Anatolii V. Moskalyuk ◽  
Sergey V. Yarema ◽  
Igor I. Panko ◽  
Miroslav O. Stasyk
Keyword(s):  
Distribution Function ◽  
Size Distribution ◽  
Chemical Reaction ◽  
Size Distribution Function ◽  
Cluster Growth ◽  
Total Flow ◽  
Cluster Surface ◽  
Rate Of Growth

The process of coarsening of nanoclusters or nanocrystals (NCs) is investigated for the case when cluster growth (dissolution) is governed simultaneously by both diffusion along dislocation pipes and the rate of formation of chemical connections (chemical reaction) at cluster surface, namely, Wagner’s growing mechanism. For that, the total flow of atoms to (from) a cluster is represented by two parts, namely, diffusion part and the Wagner (kinetic) one. The dependence of the rate of growth of NC on the ratio of the parts of the total flow has been determined as well as the NC’s size distribution function referred to as the Wagner-Vengrenovich distribution. Computed distribution is compared with experimentally obtained histograms.

Directional observation on lipid of male nectary of Lindera megaphylla hemsl. by the rapid embedding method with polyethylene glycol (PEG)

1990 ◽  
Vol 48 (3) ◽  
pp. 718-719
Author(s):  
Dai Dalin ◽  
Guo Jianmin
Keyword(s):  
Electron Microscope ◽  
Polyethylene Glycol ◽  
Chemical Reaction ◽  
Traditional Method ◽  
Osmium Tetroxide ◽  
Unsaturated Lipid ◽  
Embedding Method ◽  
Long Period ◽  
New Methods

Lipid cytochemistry has not yet advanced far at the EM level. A major problem has been the loss of lipid during dehydration and embedding. Although the adoption of glutaraldehyde and osmium tetroxide accelerate the chemical reaction of lipid and osmium tetroxide can react on the double bouds of unsaturated lipid to from the osmium black, osmium tetroxide can be reduced in saturated lipid and subsequently some of unsaturated lipid are lost during dehydration. In order to reduce the loss of lipid by traditional method, some researchers adopted a few new methods, such as the change of embedding procedure and the adoption of new embedding media, to solve the problem. In a sense, these new methods are effective. They, however, usually require a long period of preparation. In this paper, we do research on the fiora nectary strucure of lauraceae by the rapid-embedding method wwith PEG under electron microscope and attempt to find a better method to solve the problem mentioned above.

Effects of Retinoic Acid and 1,25-Dihydroxyvitamin D3 on IFN-gamma Secretion by Mononuclear Leukocytes from Nulliparous and Postparturient Dairy Cattle

2000 ◽  
Vol 70 (3) ◽  
pp. 92-101 ◽  
Author(s):  
Burim Ametaj ◽  
Brian Nonnecke ◽  
Ronald Horst ◽  
Donald Beitz
Keyword(s):  
Retinoic Acid ◽  
Dairy Cattle ◽  
Dairy Cows ◽  
Dairy Cow ◽  
Pokeweed Mitogen ◽  
Mononuclear Leukocytes ◽  
Combined Effects ◽  
Ifn Gamma ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D

Individual and combined effects of several isomers of retinoic acid (RA) and 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) on interferon-gamma (IFN-gamma) secretion by blood mononuclear leukocytes (MNL) from nulliparous and postparturient Holstein cattle were evaluated in vitro. In the first experiment, effects on incubation period (24 to 72 hours) and time of supplementation (0 to 32 hours) with all-trans, 9-cis, 13-cis-, and 9,13-dicis-RAs (0 to 100 nM) on IFN-gamma secretion by pokeweed mitogen (PWM)-stimulated (0 and 10 mug/ml) MNL from nulliparous cattle were evaluated. In the second experiment, MNL from postparturient cows (bled at 0, 2, 4, and 16 days postpartum) were stimulated with PWM (0 and 10 mug/ml) in the presence of RA isomers (9-cis- or 9,13-dicis-RA; 0 to 100 nM), 1,25-(OH)2D3 (0 to 100 nM), or with combinations of these metabolites. The results show that individual isomers of RA had no effect on IFN-gamma secretion by PWM-stimulated MNL from nulliparous or postparturient cows. Furthermore 1,25-dihydroxyvitamin D3 inhibited IFN-gamma secretion by MNL from nulliparous and postparturient dairy cows; however, the degree of inhibition was greater when 9-cis- and 9,13-dicis-RA were also present in the cultures. Finally mononuclear leukocytes from postparturient dairy cows produced substantially less IFN-gamma than did MNL from nulliparous cattle. It is concluded that retinoic acids individually did not affect the capacity of leukocytes from dairy cattle to secrete IFN-gamma. This result is in marked contrast to studies in monogastric species indicating that RAs inhibit IFN-gamma secretion by peripheral blood T cells. Inhibition of IFN-gamma secretion by 1,25-(OH)2D3 was potentiated by 9-cis- and 9,13-di-cis-retinoics acids, suggesting that an excess of dietary vitamins A and D may compromise further the naturally immunosuppressed postparturient dairy cow. Additional research is necessary to determine if the combined effects of these metabolites on IFN-gamma secretion represent an increased susceptibility of the dairy cow to infectious diseases during the periparturient period. Lower secretion of IFN-gamma by MNL from postpartutient dairy cows, relative to nulliparous cattle, suggests that recently-calved cows are naturally immunosuppressed.

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