506. The importance of machine milking rate in dairy cow management and breeding

1953 ◽  
Vol 20 (2) ◽  
pp. 138-145 ◽  
Author(s):  
F. H. Dodd ◽  
A. S. Foot

An analysis has been carried out on the milk yield, milk composition and milking-rate records collected in one herd of dairy cows.It has been shown from the results of eighty-six heifers that for each pound per minute increase in inherent milking rate (i.e. peak flow) the standard lactation yield increases by 419 lb., the maximum daily yield by 0·9 lb., the lactation length by 8 days and the persistency index by 10 days, whilst the lactation solids-not-fat percentage decreases by 0·03 and the fat percentage by 0·04. All except the last coefficient were significant, although it was also shown that the relationship with solids-not-fat percentage was due to an interaction. Similarly, by the calculation of partial regression coefficients it was demonstrated that the relationship between milking rate and standard lactation yield was due to the effect of milking rate on maximum daily yield, lactation length and persistency.

1971 ◽  
Vol 13 (2) ◽  
pp. 353-356 ◽  
Author(s):  
M. E. Castle ◽  
R. Henderson

SUMMARYRecords of milking rate, milk yield and milk composition were collected over 12 yr from 123 Ayrshire heifers in their first lactation in one herd. Three direct measures of milking rate, i.e. peak flow rate, machine rate and overall rate were closely correlated and each was also correlated with total lactation yield of milk. Milking rate accounted for only a very small part of the variation in fat and total solids percentages. The mean yield of milk per milking in early lactation was a better predictor of total lactation yield than was milking rate but, among animals giving the same early lactation yield of milk, the faster milkers gave higher lactation yields than the slower milkers.


1996 ◽  
Vol 76 (3) ◽  
pp. 429-433 ◽  
Author(s):  
D. T. Fairey ◽  
N. A. Fairey ◽  
L. P. Lefkovitch

Most of the genetic diversity of North American alfalfa cultivars has been accounted for by nine germplasm sources listed in descending order of winter hardiness as follows: Medicago sativa ssp. falcata, Ladak, M. sativa ssp. xvaria, Turkistan, Flemish, Chilean, Peruvian, Indian and African. In most instances, the breeder assigns a fall dormancy score and the relative proportions of each of the nine germplasm source for each cultivar at registration. The fall dormancy score (1 = dormant to 9 = non-dormant), determined by measuring plant height in October after harvest in early September, is used to indicate cultivar adaptation for different regions. This study examines the relationship between germplasm composition and plant height, the equivalence of fall dormancy. The signs on the partial regression coefficients of a multiple regression analysis of plant height on the proportional content of the nine sources of germplasm showed that the fall dormancy fell essentially into two classes, namely, a dormant category, comprising cultivars containing a large contribution of Falcata and Ladak, and a non-dormant category, in which Indian and African germplasm predominate. This does not necessarily preclude the influence of any of the other germplasm sources on fall dormancy, since they represent a rich source of diversity. However, nine distinct classes were not recognisable, perhaps because of the lack of an exact equivalence between fall dormancy class and plant height of the fall regrowth. Since these observations have not been derived in a common nursery, the latitude and latitude × cultivar effects have been disregarded. These limitations should be recognized when using the currently assigned fall dormancy ratings to predict cultivar adaptation. Key words: Alfalfa, fall dormancy, sources of germplasm


2009 ◽  
pp. 69-73
Author(s):  
Edit Mikó Józsefné Jónás ◽  
Imre Mucsi ◽  
István Komlósi

The authors examined the data of 2767 trial milkings andthe months Body Condition Scores of 479 Holstein dairy cows. The condition loss was significant between the 30-60th days. The improvement of BCS begins only after the 120th day. The change in the milk protein and milk fat content were close after the condition changing. In each period of the lactation the closeness of the relationship among the condition, the milk quantity and the milk composition were different. In the aspect of the milk quantity the most significant difference was between the 2.5 and 4 BCS cows (6.68 kg) in the last period of the lactation.


2011 ◽  
Vol 27 (4) ◽  
pp. 1433-1441
Author(s):  
M.D. Petrovic ◽  
V. Bogdanovic ◽  
M.M. Petrovic ◽  
S. Rakonjac

The relationship between milk production traits over whole lactations was evaluated across three generations of Simmental cows, i.e. between daughters, dams and grand dams, by a phenotypic regression analysis with whole lactation traits in the daughter generation being used as the dependent variables (x1), and those in the dam and grand dam generations being used as the independent variables (x2 and x3). The results were obtained from a sample of 1170 daughters and as many dams and grand dams. The significance of the partial regression coefficients b2 and b3 was separately evaluated by a t-test. An analysis of variance was used to estimate the significance of the simultaneous effect of the production traits of dams and grand dams on the milk production achieved in the daughter generation. The calculated value of the partial regression coefficients for the whole lactation production traits across three generations (grand dams, dams and daughters) and their statistical significances determined by the t and F tests, as well as the regression equations used, suggested that the effect of the grand dam generation on the milk production traits in granddaughters was substantially lower than the effect of dams. The calculated partial regression coefficients (b2 and b3) were positive and statistically very significant (P<0.01), excepting the regression coefficients b3 for lactation length and b2 for milk fat content that were not statistically significant (P>0.05). A very significant change (P<0.01) was observed in all production traits in the daughter generation as simultaneously affected by the traits in the dam and grand dam generations.


2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Juan Isidro Sanchez-Duarte ◽  
Alvaro Garcia ◽  
Karla Rodríguez-Hernández ◽  
David G. Reta-Sánchez ◽  
Homero Salinas-Gonzalez ◽  
...  

The objective was to evaluate the effects of two (2×) vs three (3×) times per day milking on milk production and milk composition in dairy cows. Fourteen scientific papers, containing production data from 16 trials, where dairy cows were milked 2× or 3×, were analysed using meta-analysis with fixed and random-effects with the R statistical program. The degree of heterogeneity and publication bias were measured with the I2 statistic and Begg’s test, respectively. In addition, the meta-regression analysis explored other sources of heterogeneity for the response. The estimated effect size of 2× and 3× milkings was calculated for dry matter intake (DMI), milk production, and milk composition. Dry matter intake, milk production, and milk fat and protein yields showed substantial heterogeneity (I2>50%). Whereas milk fat-percentage had moderate heterogeneity (I2<50%), and milk protein had no (I2=0%)heterogeneity. The year of publication, trial duration, and cattle breed did not influence production response parameters to milking frequency. We found no evidence of publication bias for the parameters evaluated (Begg’s test; P>.05). Cows milked 2× produced less milk (2.23 kg/d), less milk fat (0.06kg/d), and less milk protein (0.05 kg/d). In contrast, the fat percentage was lower (0.07 units) in 3×, compared with 2× milking frequency. There was no effect of milking frequency on DMI and milk protein percentage. In conclusion, milk production and milk fat and protein yields improves as milking frequency increase from 2× to 3× daily, without affecting DMI. The implementation of 3× milking frequency must consider dairy cow management, labor, and milking parlour infrastructure, particular to each dairy farm.


2003 ◽  
Vol 2003 ◽  
pp. 125-125
Author(s):  
T. Goodman ◽  
N. Gardner ◽  
C. Lord ◽  
A. Nickson ◽  
J. Long

High levels of dietary concentrates are often used to support milk production and it is important to investigate ways to feed them efficiently. Fats have the greatest energy density of any feed ingredient and the inclusion of protected fats in the dairy cow ration enables a high energy but balanced ration to be fed. The aim of this trial was to investigate the effect of feeding different levels of Megalac (Volac International Ltd, Herts) to dairy cows and to compare milk yield, milk composition, fertility and body condition score (BCS).


1965 ◽  
Vol 65 (3) ◽  
pp. 379-387 ◽  
Author(s):  
J. L. Beveridge ◽  
R. H. Jarvis ◽  
W. J. Ridgman

1. The problem of when to apply nitrogenous top-dressings to winter wheat has nover been satisfactorily solved. Detailed field and glasshouse experiments on the effects of nitrogenous manuring on the development of wheat plants, and a number of other experiments involving the nitrogenous manuring of wheat are described and the results discussed.2. Partial regression coefficients of grain yield on individual components of yield are used to show how variable is the relationship between grain yield and the components of yield.3. It is concluded that field experiments are never likely to determine an optimum time for nitrogen top-dressing because of the unpredictable relationships between individual yield components and grain yield, and because of the variation in response to nitrogen introduced by seasonal and environmental factors.


1976 ◽  
Vol 16 (81) ◽  
pp. 445 ◽  
Author(s):  
H Jeffery ◽  
RF Buesnel ◽  
GH O'Neill

Milk production of grazing dairy cows receiving 3 kg per day of wheat, sorghum, maize, oats or barley was measured. In general, only small differences were observed in the yield and composition of milk produced from cows consuming the different grains. Two experiments were conducted to investigate the relationship between the milk response of grazing dairy cows to 3 kg supplement and their level of production, stage of lactation, and age. Similar mean responses to supplementation were found in both experiments but no consistent relationship between response and either level of production, stage of lactation or age was found. A further experiment examined the response of grazing dairy cows, grouped into four groups according to their level of production, to 3, 4.1/3 5.2/3, 7 or 8.5 kg supplement per day. These treatments had a non-significant effect on milk composition; as the rate of supplementation increased, the yield of milk and its constituents first increased then commenced to decrease. The response obtained from both low and high producing cows was similar. It was thus concluded that in the short-term neither the type of grain fed, the cow's age, level of production nor stage of lactation affected its response to supplementation. The dichotomy between this conclusion and the widespread view that high producers respond better to supplementation is discussed.


1999 ◽  
Vol 59 (1) ◽  
pp. 1-11 ◽  
Author(s):  
M Åkerlind ◽  
K Holtenius ◽  
J Bertilsson ◽  
M Emanuelson

1959 ◽  
Vol 26 (2) ◽  
pp. 134-139 ◽  
Author(s):  
G. A. Lodge

1. Data are given on the changes which occurred in the composition of sow's milk during the course of 24 lactations. The mean percentages of the major constituents (192 samples) were: total solids, 20·0%: crude protein, 5·7%: lactose, 4·7%; fat, 8·6% and ash, 0·89%.2. There were differences in milk composition between sows and between successive lactations, but these were only appreciable for milk fat percentage between sows.3. A highly significant negative correlation (P < 0·001; r = –0·62) was found to exist between the percentages of protein and lactose in the milk, quite apart from the general trend for protein content to fall with advance in lactation. Possible reasons for this are discussed.


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