scholarly journals Lactation curves and persistency of White Fulani and Sokoto Gudali lactating cows

2020 ◽  
Vol 44 (4) ◽  
pp. 29-37
Author(s):  
O. E. Odegbile ◽  
I. I. Adedibu ◽  
C. Alphonsus
Keyword(s):  
Milk Yield ◽  
Preliminary Analysis ◽  
Post Partum ◽  
Prediction Equation ◽  
Coefficient Of Determination ◽  
Lactation Period ◽  
Lactating Cows ◽  
Lactation Curve ◽  
Breeding Programmes ◽  
White Fulani

The aim of this study was to determine the lactation curve traits of White Fulani (WF) and Sokoto Gudali (SG) lactating cows. Wood's gamma and Wilmink's curve parameters were employed to identify the lactation curve types and values for the parameters beginning yield (a) , coefficient of rising (b), coefficient of decreasing (c)t=timeande= is the exponential.The parameter assumed a fixed value derived from a preliminary analysis and disassociated with the time at peak yield were used to determine the shape and type of lactation curve. All Parameters in a typical lactation curves were positive, and in the event of one parameter being negative, the curve was considered to be an atypical lactation curve. Lactation records from WF (n=96)and SG (n=130) cows were recorded in the study area between year 2016-2017. Cows were hand-milked twice per day in the morning and evening from the 5 day post-partum till the end of the lactation period (260-270 days).Prediction equation of milk yield showed R values ranging from (32.00) in the SG to (35.00) in the WF. It was observed that the Wood's model curves were typical while Wilmink's model curves were atypical respectively. For typical lactation curves, a, b, c, persistency (S), time after parturition until the peak yield occurs (T ), maximum daily peak yield (Y ), and coefficient of determination (R ) were - 0.25±0.13, 1.08±0.07, 0.23±0.19, 2.34,51.00,2.62 and 97 for WF lactating cows and - 0.23 ± 0.14,1.13 ± 0.08, 0.07± 0.03, 2.33, 51.26, 2.58 and 96 for SG Lactating cows respectively. Parameters predicted by the Wood's model have the potential of being useful for breeding programmes in the SG and WF cows.  

The control of appetite in lactating cows

1972 ◽  
Vol 14 (3) ◽  
pp. 263-281 ◽  
Author(s):  
L. S. Monteiro
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Milk Yield ◽  
Closed Loop ◽  
Loop System ◽  
Closed Loop System ◽  
Lactating Cows ◽  
Body Reserves ◽  
Lactation Curve ◽  
Rate Of Increase

SUMMARYA closed-loop system is proposed for the control of voluntary food intake in lactating cows, and an expression is deduced relating the response of food intake to changes in milk yield and body-weight gain.A closed-loop system necessarily involves a delay in the response to changes in production. The rate of increase of food intake is there- fore slower than the rate of increase in milk yield. The consequent deficit in energy during the rising part of the lactation curve is met by the mobilization of body reserves, which are partly accounted for by losses in body weight. During the declining part of the lactation the delay effect leads to an excess of energy intake and to the replacement of body reserves and, consequently, of body weight.The expression deduced from the model was fitted to four different types of lactation curve corresponding to long and short lactations of Friesians and Jerseys fed ad libitum on a complete diet. The expected food intake based on the control model was contrasted with a linear regression model. The former gave a better account of the variation in food intake in all four types of lactation.The total change in body weight during lactation was partitioned between changes in weight due to the mobilization and replacement of reserves and gain directly attributable to food intake. There was, in general, good agreement between the observed losses in weight occurring at the beginning of lactation and those predicted from the mobilization of reserves for milk production.The physiological implications of the model and the values estimated for the parameters are discussed.

scholarly journals The use of dijkstra mechanistic model for genetic analysis of the lactation curve characteristics and their relationships with age at first calving and somatic cell score of Iranian dairy cows

2020 ◽  
Vol 42 ◽  
pp. e50181
Author(s):  
Mahdi Elahi Torshizi ◽  
Homayoun Farhangfar
Keyword(s):  
Somatic Cell ◽  
Genetic Correlation ◽  
Milk Yield ◽  
Mechanistic Model ◽  
Genetic Correlations ◽  
Somatic Cell Score ◽  
Specific Rate ◽  
Lactation Period ◽  
Age At First Calving ◽  
Lactation Curve

The objective of this study was to estimate lactation curve parameters with Dijkstra mechanistic model and to evaluate genetic and phenotypic relationships between the parameters and the average somatic cell count in primiparous cows. The finding indicated that heritability estimates for partial milk yield (PMY1, PMY2 and PMY3), total 305-day milk yield (TMY305), decay parameter (λ2), age at first calving (AFC) and peak yield (PY) were moderate while the heritability of persistency (PS%), average somatic cell score (AVGSCS), time to peak yield (TP), initial milk production (λ0), specific rate of cell proliferation at parturition (λ1), and specific rate of cell death (λ3) were quite low. Genetic correlations between both AFC and PS% traits with average somatic cell scores was negative (-0.047 and -0.060) but low positive genetic correlation were between partial milk yields (PMY1 and PMY3) while negative genetic correlation (-0.06) was obtained between TMY305 and AVGSCS. Differences between TMY305 of cows with less than 100000 cells mL-1 and cows with >1,500,000 cells mL-1 was approximately 708 Kg and is equivalent to 8% loss of milk yield/cow during lactation period and also loss of persistency (11.1 %( was shown for the extreme classes of SCC in this study.

scholarly journals On designing the average lactation curve at the ascending phase

1962 ◽  
Vol 34 (1) ◽  
pp. 162-168
Author(s):  
Aarne Mäkelä
Keyword(s):  
Dairy Cows ◽  
Milk Yield ◽  
Lactation Period ◽  
Lactation Curve ◽  
The Mean ◽  
The Individual ◽  
Daily Milk Yield ◽  
Daily Milk

Comparisons are made between different methods to find the peak production (maximum daily milk yield) and methods to design the average lactation curve at the ascending phase in dairy cows. It was noted that in order to determine the height and location of the maximal producing capacity of a cow in a known lactation period, it is preferable to choose the peak production as a mean of three subsequent best days. It was also noted that the usual methods for drawing the average lactation curves do not give a true picture of the height and location of the peak. The author suggests a method for determining the average lactation curve at the ascending phase by using the averages of both milk productions and times involved in reaching the peak and known fractions (e.g. 1/8, 1/4, 1/2, 3/4, and 5/4) of it. In this lactation curve the peak production is the mean of the peaks of individual cows, and the time involved in reaching it is the mean of the durations of the ascending phases of the individual cows.

Introducing a sinusoidal equation to describe lactation curves for cumulative milk yield and composition in Holstein cows

2020 ◽  
Vol 87 (2) ◽  
pp. 220-225
Author(s):  
Navid Ghavi Hossein-Zadeh ◽  
Hassan Darmani Kuhi ◽  
James France ◽  
Secundino López
Keyword(s):  
Linear Model ◽  
Milk Yield ◽  
Milk Fat ◽  
Goodness Of Fit ◽  
Growth Models ◽  
Information Criterion ◽  
Holstein Cows ◽  
Coefficient Of Determination ◽  
Production Traits ◽  
Lactation Curve

AbstractThe aim of the work reported here was to investigate the appropriateness of a sinusoidal function by applying it to model the cumulative lactation curves for milk yield and composition in primiparous Holstein cows, and to compare it with three conventional growth models (linear, Richards and Morgan). Data used in this study were 911 144 test-day records for milk, fat and protein yields, which were recorded on 834 dairy herds from 2000 to 2011 by the Animal Breeding Centre and Promotion of Animal Products of Iran. Each function was fitted to the test-day production records using appropriate procedures in SAS (PROC REG for the linear model and PROC NLIN for the Richards, Morgan and sinusoidal equations) and the parameters were estimated. The models were tested for goodness of fit using adjusted coefficient of determination $\lpar {R_{{\rm adj}}^2 } \rpar $, root mean square error (RMSE), Akaike's information criterion (AIC) and the Bayesian information criterion (BIC). $R_{{\rm adj}}^2 $ values were generally high (>0.999), implying suitable fits to the data, and showed little differences among the models for cumulative yields. The sinusoidal equation provided the lowest values of RMSE, AIC and BIC, and therefore the best fit to the lactation curve for cumulative milk, fat and protein yields. The linear model gave the poorest fit to the cumulative lactation curve for all production traits. The current results show that classical growth functions can be fitted accurately to cumulative lactation curves for production traits, but the new sinusoidal equation introduced herein, by providing best goodness of fit, can be considered a useful alternative to conventional models in dairy research.

scholarly journals Modelling of the lactation curve of grazing Mongolian mare

2020 ◽  
Vol 29 (1) ◽  
pp. 64-71
Author(s):  
Sandagdorj Badrakh ◽  
Baigalmaa Tserenpil ◽  
Burenjargal Sedkhuu ◽  
Nyam-Osor Purevdorj
Keyword(s):  
Mathematical Models ◽  
Milk Yield ◽  
Lactation Period ◽  
Linear Quadratic ◽  
Quartic Curve ◽  
Lactation Curve ◽  
Total Milk ◽  
Curve Model ◽  
Composition Curve ◽  
Best Fit

Current research was performed to determine the yield and composition of milk during entire lactation period, which lasts June to February of following year and describe fit of lactation curve using different mathematical models. Total 8 mares, aged from 5 to 12 years were used in the study. The total milk yield, calculated by Fleischmann's method, as well as the models were various and shape of curves for Linear, Quadratic, Cubic, and Quartic equations, and Wood's curve were different. The determination index (R2) of the milk yield and composition curve models ranged from 0.474-0.987, and R2 of Quartic curve model for milk yield (0.987) was the highest. Study result showed that the above models were able to describe the lactation curve of the milk yield and composition, and the Quartic model best fit to data collected from Mongolian mare and allowed a suitable description of the shape and dynamics of curve. Бэлчээрийн маллагаатай Монгол гүүний лактацын муруйн загварчлал Монгол гүүний саалийн нийт хугацаанд буюу VI сараас дараа жилийн III сар хүртэл саамны гарц, найрлагын хэмжээг үндэслэн математик загваруудаар лактацын муруй байгуулах, монгол гүүний лактацын муруйд хамгийн нийцэл сайтай загварыг сонгон тодорхойлох зорилгоор энэхүү ажлыг хийж гүйцэтгэлээ. Судалгаанд 5-12 насны 8 гүүг ашиглав. Сүүний нийт гарц, найрлагын хэмжээг Вүүд (Wood’s)-ын загвар болон шугаман, шугаман бус регрессын тэгшитгэлээр загварчлахад лактацын муруйн загварууд харилцан адилгүй байв. Саамны гарц, найрлагын муруйн загваруудын детерминацийн индекс (R2) нь 0.474-0.987-ийн хооронд хэлбэлзэж, биквадрат загварын хувьд хамгийн нийцэл өндөр буюу 0.987 байв. Судалгааны үр дүнд дээрх аргуудаар саамны гарц, найрлагын лактацын муруйг загварчлах боломжтой нь харагдаж байсан ба эдгээрээс биквадрат тэгшитгэлийн загвар нь  бэлчээрийн маллагаатай монгол гүүний саамны өгөгдөлтэй хамгийн сайн нийцэж, лактацын муруйн хэлбэр, хөдлөлзүйн хувьд тохирч байв.   Түлхүүр үг: саамны гарц, саамны найрлага, лактацын муруй  

scholarly journals The influence of THI values at different periods of lactation on milk quality and characteristics of lactation curve

2010 ◽  
Vol 55 (3) ◽  
pp. 235-241 ◽  
Author(s):  
Marko Cincovic ◽  
Branislava Belic ◽  
Bojan Toholj ◽  
Ivan Radovic ◽  
Bojana Vidovic
Keyword(s):  
Heat Stress ◽  
Milk Yield ◽  
Milk Fat ◽  
Significant Negative Correlation ◽  
Moderate Intensity ◽  
Lactation Period ◽  
Yield And Quality ◽  
Lactation Curve ◽  
Quality Of Milk

The experiment included 90 cows. Cows were chosen according to the time of calving, so that the first third of lactation occurred during the summer in 30 cows (G1), the second third of lactation occurred during the summer in 30 cows (G2), and in the last 30 cows the last third of lactation was in summer period (G3). The value of THI was between 72 and 82, which indicates the existence of the moderate intensity of heat stress. Heat stress does not damage the milk yield, milk fat and protein percentage on the level of the whole lactation, regardless of the lactation period in which the cows were exposed to stress. There was no correlation between THI and milk yield and quality at the level of the whole lactation. Heat stress did not show a significant effect on the parameters of lactation curve, except the peak of yield, which occurred later in cows exposed to heat stress. Increased value of THI showed nonsignificant effect on yield and quality of milk in the first third of lactation. In the middle and at the end of lactation THI was in a significant negative correlation with the yield and quality of milk. Our study showed a significantly lower heat-induced milk yield, milk fat and protein percent in the middle and at the end of lactation.

Characterisation of the Lactation Curve in Pakistani Buffaloes

1984 ◽  
Vol 1984 ◽  
pp. 136-136
Author(s):  
K.Z. Gondal ◽  
P. Rowlinson
Keyword(s):  
Milk Yield ◽  
Indian Subcontinent ◽  
Human Consumption ◽  
Dairy Herds ◽  
Lactation Period ◽  
General Shape ◽  
Or Groups ◽  
Lactation Curve ◽  
Total Milk ◽  
Dairy Animals

The rate of milk secretion in dairy animals displays a trend throughout the lactation period. It increases to a maximum in a few weeks following parturition and decreases thereafter until the animal goes dry.This trend draws a certain curve, namely the lactation curve.The milk yield of a single lactation may be influenced by many factors but the general shape of the lactation curve defined by the locus of weekly yields remains substantially unchanged. It rises rapidly to the peak within a few weeks after calving followed by a more or less gradual decline until the end of lactation.The analysis of the lactation curve, i.e. the week to week output of milk and trend of increase and decrease in yield with advancement of lactation is important for day to day management and forward planning of dairy herds by reliable forecasting of week by week milk production, seasonal variation and the total milk yield of individual cows or groups of cows.A number of reports pertaining to dairy cattle have been published but very few studies have been concerned with buffaloes. In most of the countries, the buffaloes have been used for draught purpose but it is in the Indian subcontinent that this animal is seen at its greatest advantage as a source of animal protein, i.e. milk and meat for human consumption.

Application of the Wood model to analyse lactation curves of organic dairy sheep farming

2014 ◽  
Vol 54 (10) ◽  
pp. 1609 ◽  
Author(s):  
Juan Carlos Ángeles Hernández ◽  
Octavio Castelán Ortega ◽  
Benito Albarrán Portillo ◽  
Hugo H. Montaldo ◽  
Manuel González Ronquillo
Keyword(s):  
Milk Yield ◽  
Goodness Of Fit ◽  
Evaluation Criteria ◽  
Coefficient Of Determination ◽  
Dairy Sheep ◽  
Organic System ◽  
Dairy Ewes ◽  
Lactation Curve ◽  
Total Milk ◽  
Wood Model

The aim of the present study was to evaluate the performance of the Wood model to describe the characteristics of lactation curves of dairy ewes under organic management in Mexico. In total, 4861 weekly test-day milk yield records from 194 lactations of crossbred dairy ewes were analysed to assess the performance of an empirical model to fit their lactation curve. We used the mathematical model proposed by Wood. The evaluation criteria were the correlation coefficient (r) between the values of total milk yield observed and estimated, the coefficient of determination (R2), and the mean square prediction error (MSPE). In addition, the peak yield (PYest) and time at peak yield (PTest) were calculated. The Wood model showed adequate goodness of fit (r = 0.95, R2 = 0.92 and MSPE = 0.024). The Wood model detected that 52.06% of lactation curves had a continuously decreasing shape (atypical curve), probably as a consequence of the characteristic management of the organic system, mainly due to the genotype used and the nutritional management. Residuals were greater for atypical curves than for typical ones, indicating differences in the ability of the Wood model to fit the two types of shapes. In typical curves, the Wood model showed adequate estimates of total milk yield and time at peak yield. The peak yield was underestimated both in typical and atypical curves. The Wood model in atypical curves underestimated the time at peak yield and milk yields in late lactation. The Wood model showed a reasonable fit of lactation curve in dairy sheep in organic systems but presented deficiencies of fit in atypical curves; therefore, estimates should be interpreted carefully.

Mastitis and the shape of the lactation curve in Norwegian dairy cows

2010 ◽  
Vol 78 (1) ◽  
pp. 23-31 ◽  
Author(s):  
Fredrik Andersen ◽  
Olav Østerås ◽  
Olav Reksen ◽  
Yrjo T Gröhn
Keyword(s):  
Incidence Rate ◽  
Milk Yield ◽  
Mixed Model ◽  
Steep Slope ◽  
Rapid Decline ◽  
Lactation Period ◽  
Herd Level ◽  
Management Interventions ◽  
Lactation Curve ◽  
Norwegian Dairy

An investigation of the shape of the lactation curve and the mastitis incidence was conducted to identify whether management interventions of the lactation curve constitute a potential for reducing incidence of mastitis at herd level. Lactation curves were estimated to describe the variation of daily milk yield during the 305-d lactation period in Norwegian Red cows. Associations between mastitis incidence at herd level and lactation curve characteristics such as production level at onset of lactation, magnitude and time of peak milk yield, and increase and decrease of milk yield rates were studied. Data from 250 303 lactations occurring during 2005 and 2006 from 14 766 herds were obtained from the Norwegian Dairy Herd Recording System. Besides veterinary treatments, the records included information on monthly test-day milk yields. The shapes of the lactation curves at herd level were parameterized using a modified Wilmink model in two separate mixed model analyses. In the first analysis a subset of lactations with no records of veterinary treatments was used. Lactation curves from herds with high (>0·31 cases/305-d lactation) and low (<0·07 cases/305-d lactation) herd mastitis incidence rate were parameterized and compared for three separate strata of parity. The result showed that high herd mastitis incidence rate was associated with a low intercept (P<0·05), a steep slope before peak milk yield (P<0·01) and a rapid decline after peak milk yield (P<0·01). In the second analysis a subset of high-yielding lactations with veterinary treatments of mastitis only and lactations with no records of veterinary treatment were compared. This was done to investigate whether the findings at herd level were also reflected at cow level. These results showed that lactation curves from lactations with mastitis cases were associated with a steep slope before peak milk yield (P<0·05) in second and later parities and a rapid decline after peak milk yield (P<0·01) in all three parity groups.

scholarly journals Comparison of the parameters of the lactation curve between normal and difficult calvings in Iranian Holstein cows

2019 ◽  
Vol 17 (1) ◽  
pp. e0401
Author(s):  
Navid Ghavi Hossein-Zadeh
Keyword(s):  
Dairy Cows ◽  
Milk Yield ◽  
Goodness Of Fit ◽  
Linear Models ◽  
Information Criterion ◽  
Holstein Cows ◽  
Coefficient Of Determination ◽  
Lactation Curve ◽  
Non Linear ◽  
Best Fit

To evaluate effect of dystocia on the lactation curve characteristics for milk yield and composition in Holstein cows, six non-linear models (Brody, Wood, Sikka, Nelder, Dijkstra and Rook) were fitted on 5,917,677 test day records for milk yield (MY), fat (FP) and protein (PP) percentages, fat to protein ratio (FPR) and somatic cell score (SCS) of 643,625 first lactation Holstein cows with normal calving or dystocia from 3146 herds which were collected by the Animal Breeding Center of Iran. The models were tested for goodness of fit using adjusted coefficient of determination, root means square error, Akaike’s information criterion and Bayesian information criterion. Rook model provided the best fit of the lactation curve for MY and SCS in normal and difficult calvers and dairy cows with dystocia for FP. Dijkstra model provided the best fit of the lactation curve for PP and FPR in normal and difficult calvers and dairy cows with normal calving for FP. Dairy cows with dystocia had generally lower 100-d, 200-d and 305-d cumulative milk yield compared with normal calvers. Time to the peak milk yield was observed later for difficult calvers (89 days in milk vs. 79 days in milk) with lower peak milk yield (31.45 kg vs. 31.88 kg) compared with normal calvers. Evaluation of the different non-linear models indicated that dystocia had important negative effects on milk yield and lactation curve characteristics in dairy cows and it should be reduced as much as possible in dairy herds.

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