scholarly journals Holsteins in Puerto Rico: I. Influence of Herd, Year, Age, and Season on Performance

1969 ◽  
Vol 60 (4) ◽  
pp. 526-539
Author(s):  
J. K. Camoens ◽  
R. E. McDowell ◽  
L. D. Van Vleck ◽  
J. D. Rivera Anaya
Keyword(s):  
Puerto Rico ◽  
Total Variation ◽  
Milk Yield ◽  
Seasonal Effects ◽  
Dry Period ◽  
Factors Affecting ◽  
Lactation Length ◽  
Days Open ◽  
Fat Yield ◽  
Selection For

The effects of herd, year, age, season, and their interactions on milk and fat yield, fat percent, days in milk, days dry, and days open for purebred and high grade Holsteins in a tropical environment were determined by analysis of variance using DHIA records from Puerto Rico. There were 33,950 records for calvings from 1967 to 1973 in 62 herds. Herd effects were significant (P < .05) for all traits, but seasonal effects were significant only for milk yield, fat yield, and days open. Variation among herds significantly influenced all traits except milk yield. Age of calving affected all traits except lactation length and days open. A number of the interactions were also significant. The statistical model explained 39, 40, 24, 17, 13 and 12% of the total variation in milk yield, fat yield, fat percent, lactation length, days dry, and days open, respectively. Total variances were 12,900,000 lb2 for milk yield and 15,000 lb2 for fat yield, which are comparable to those for temperate areas. It is concluded that the factors affecting the performance of Holsteins in Puerto Rico do not differ markedly from those in temperate countries. The total variation appears large enough to permit selection for higher milk and fat yields. As in temperate regions, length of lactation, length of dry period, and time of rebreeding (days open) are largely influenced by decisions made on the part of herd owners.

scholarly journals Holsteins in Puerto Rico: II. Influence of Lactation Length, Days Dry, Days Open, and Calving Interval on Production Traits

1969 ◽  
Vol 60 (4) ◽  
pp. 540-550
Author(s):  
J. K. Camoens ◽  
R. E. McDowell ◽  
L. D. VanVleck ◽  
J. D. Rivera Anaya
Keyword(s):  
Puerto Rico ◽  
Milk Yield ◽  
Phenotypic Correlation ◽  
Calving Interval ◽  
Production Traits ◽  
Dry Period ◽  
Lactation Length ◽  
Order Of Magnitude ◽  
Days Open ◽  
Fat Yield

Records of high grade or purebred Holsteins in 62 herds on DHIA recording in Puerto Rico were used to determine phenotypic correlations of lactation length, days dry prior to lactation, days open during lactation, and interval from previous parturition (calving interval) to lactation, milk and fat yields, and fat percent. Both milk and fat yields had a significant (P < .05) positive phenotypic correlation with lactation length, calving interval, and days open (0.178 to 0.658), hut fat percent had a low relation to these traits (-0.023 to +0.014). Lactation length, dry period, days open, and calving interval were regressed on milk yield, fat yield, and fat percent. The combined contribution of these variables to variation in milk yield was 44.4%. Days open, days dry, and calving interval accounted for only 13.4% of the variation in milk yield. Days dry and days open together accounted for 9.6% of the variation, and days dry, plus calving interval, made up 6.0%, of the variation. The values for fat yield were slightly lower but followed a similar pattern as for milk yield. The four variables combined contributed only 0.23% to the variance in fat percent. Total milk yield and fat yield were inf1uenced by lactation length, calving interval, and days dry in descending order of magnitude. Days open had comparatively little influence on either milk or fat yields. Length of dry period influenced fat percent more than any other variable but to little extent. Since the majority of the variation in milk and fat yields attributed to the four variables was due to lactation length, it appears that in Puerto Rico selection with emphasis on lactation yields is unlikely to decrease fertility.

scholarly journals Holsteins in Puerto Rico: III. Components of Variance Associated with Production Traits and Estimates of Heritability

1969 ◽  
Vol 60 (4) ◽  
pp. 551-558
Author(s):  
J. K. Camoens ◽  
R. E. McDowell ◽  
L. D. VanVleck ◽  
J. D. Rivera Anaya
Keyword(s):  
Puerto Rico ◽  
Milk Yield ◽  
Variance Components ◽  
The United States ◽  
Production Traits ◽  
Genotypic Variance ◽  
Components Of Variance ◽  
Lactation Length ◽  
Days Open ◽  
Fat Yield

Variance components were estimated for herd, sire, and cow effects with a three-way nested model, using unadjusted and adjusted records for age and seasonal difference from 62 herds on DHIA recording in Puerto Rico. The cows calved from 1967 to 1973. They were high grade and purebred Holsteins imported from Canada or the United States or progeny of bulls and semen from the two countries. The percentages of the total variance for milk yield were 18.7, 4.9, and 40.8% for herd, sire, and cow, respectively. The percentages for fat yield were similar. These, plus the component for lactation length and days open, were in the range reported from temperate regions. The variance components of fat percent were similar to that of temperate regions for herd ( 14.9%) and cow (54.1%), but the sire component was negative, indicating factors yet unidentified that influenced this trait. Total variances for milk and fat yields indicated sufficient variability to permit selection. Estimates of heritability and repeatability for milk yield, fat yield, fat percent, lactation length, and days open computed from the sire and cow variance components were consistent with those reported from the temperate regions. The estimates indicate there was no loss of genotypic variance in the tropical environment. It appears that genotype exerts as much influence on production in Puerto Rico as elsewhere.

scholarly journals Determining the Factors Affecting 305-Day Milk Yield of Dairy Cows with Regression Tree

2021 ◽  
Vol 9 (6) ◽  
pp. 1154-1158
Author(s):  
Serdar Genç ◽  
Mehmet Mendes
Keyword(s):  
Dairy Cows ◽  
Milk Yield ◽  
Regression Tree ◽  
Dry Period ◽  
Data Set ◽  
Tree Analysis ◽  
Factors Affecting ◽  
Lactation Length ◽  
Regression Tree Analysis ◽  
Service Period

The purpose of this study was to determine the factors affecting the 305-day milk yield of dairy cattle by using Regression Tree Analysis (RTA). The data set of this study consisted of 8 different cattle breeds grown in Turkey. Breed (B), Province (P), Lactation Length (LL), Service Period (SP), Dry Period (DP), Parity (PR), Calving Year (CY), Calving Age (CA) and Calving Month (CM) were used to predict the 305-day milk yield. Results of RTM showed that the usage of this method might be appropriate for determining the important factors that would be able to affect the 305-day milk yield (R2=71.3%). It was seen that the most important factors affecting the 305-day milk yield were the Breed, Lactation Length, Province, and Parity. Therefore, those selected factors were more efficient than the others in predicting the 305-day milk yield. RTA results also indicated that the lowest milk yield was estimated for Jersey, Jersey Crossbred, and Yerli Kara. Among the highest 305-day milk yield cows, the milk yield estimates of the cows in the second, third, fourth, fifth, and the sixth parities were found significantly higher than that of the cows in the first and seventh parities.

scholarly journals Factors affecting lactation length and effect of current lactation length on the subsequent production and reproduction in Iranian Holsteins

2013 ◽  
Vol 56 (1) ◽  
pp. 873-881 ◽  
Author(s):  
N. G. Hossein-Zadeh
Keyword(s):  
Milk Yield ◽  
Reproductive Traits ◽  
Protein Yield ◽  
Fat Percentage ◽  
Factors Affecting ◽  
Protein Percentage ◽  
Lactation Length ◽  
Linear Relationships ◽  
Fat Yield ◽  
Increasing Trends

Abstract. Calving records of Holstein cows from January 1983 to December 2006 comprising 1,190 herds with 385,102 calving events were used to evaluate factors affecting the length of lactation and effect of current lactation length on the next productive and reproductive performances of Iranian Holsteins. Statistical analyses of productive and reproductive traits in this study were performed as linear mixed models. Lactation length (LL) of cows was grouped into 10 classes from <100 days through 500 days. Average LL was 314 days in Iranian Holsteins. Primiparous cows had the greatest LL and the mean of LL increased over the years from 1983 to 2006 and spring calvers had the longest LL (P<0.05). Cows within the LL class of 500 had the greatest unadjusted milk yield, adjusted milk yield, adjusted protein yield and adjusted fat yield and also had the longest calving intervals (P<0.05). Cows within the LL classes of 150–199 and 200–249 had the greatest values of adjusted protein percentage. Also, age at calving was the lowest for the LL class of 250–299 (P<0.05). There were linear and increasing trends for unadjusted milk yield, adjusted milk yield, adjusted protein yield and adjusted fat yield over the LL classes in this study, but a linear but decreasing trend was observed for adjusted protein percentage over LL classes. On the other hand, there were non-linear relationships between adjusted fat percentage, calving interval and age at calving with LL classes in the current study.

scholarly journals Milk yield and reproductive performance of Friesian cows under Sudan tropical conditions

2007 ◽  
Vol 50 (2) ◽  
pp. 155-164 ◽  
Author(s):  
A. z. Abdel Gader ◽  
M.-K. A. Ahmed ◽  
L. M.-A. Musa ◽  
K. J. Peters
Keyword(s):  
Milk Yield ◽  
Calving Interval ◽  
Dry Period ◽  
Age At First Calving ◽  
Lactation Length ◽  
Tropical Conditions ◽  
Days Open ◽  
Daily Milk Yield ◽  
Daily Milk ◽  
Friesian Cows

Abstract. The data obtained from the dairy herd of the Arab Company for Agricultural Production and Processing (ACAPP) in a semi arid area 40 km south of Khartoum involved 337 cows with a total of 1049 records from 16 years between 1986 and 2002. The least squares means for age at first calving, calving interval, days open, lactation milk yield, daily milk yield, lactation length and dry period were 29.76±0.40 months, 433.12 ± 6.70 days, 167.79±7.08 days, 3475.53±78.89 kg, 12.29±0.28 kg, 294.10±3.62 days and 164.08 ± 6.70 days, respectively. The analysis of variance showed that the parity number had significant (p<0.05) influences on all studied traits, while year-season of calving influenced (p<0.05) age at first calving, milk yield per lactation and daily milk yield. The sire of cow influenced (p<0.05) lactation yield, daily yield, lactation length and days open. The effects of linear and quadratic regressions of both lactation yield and daily yield on length of lactation were also highly significant (p<0.01). Heritability estimates of age at first calving, calving interval, milk yield per lactation, daily milk yield, lactation length and dry period were generally low (0.098±0.104, 0.047±0.046, 0.130±0.042, 0.123±0.041, 0.172±0.062 and 0.044±0.031, respectively) except the heritability of days open which was 0.51±0.37. The productivity of the herd in this study which averaged 12.3 kg/cow/day was much lower than the expected productivity of Holstein Friesian cows, which reflects the negative impact of the prevalent environment in the Sudan. More records and economic data are required to examine the economic feasibility of raising pure Friesians under Sudan conditions.

Evaluation of extent and amount of heterogeneous variance for milk yield in Uruguayan Holsteins

2001 ◽  
Vol 72 (2) ◽  
pp. 259-268 ◽  
Author(s):  
J. I. Urioste ◽  
D. Gianola ◽  
R. Rekaya ◽  
W. F. Fikse ◽  
K. A. Weigel
Keyword(s):  
Milk Yield ◽  
Phenotypic Variance ◽  
Simple Method ◽  
Factors Affecting ◽  
Lorenz Curves ◽  
Gini Coefficients ◽  
Adjustment Procedure ◽  
Contemporary Group ◽  
Lactation Length ◽  
Log Linear

AbstractThe extent and amount of heterogeneous phenotypic variance for milk yield in the Uruguayan Holstein population were evaluated and a simple method of accounting for heterogeneity was developed. Lactation records (159 169) collected between 1989 and 1998 by two recording schemes were used to form 8955 herd-year-season-parity-lactation length contemporary groups. A log-linear model was used to identify factors affecting heterogeneity of phenotypic variance. The model included effects of production level, contemporary group size, recording scheme, herd, season of calving, parity number, calving year period and length of lactation and accounted for 50% of the variation in log variances. Estimates from this model were used in a Bayesian manner, to obtain posterior mean estimates of within-contemporary-group variances, which were then used to standardize records to a baseline variance. Effects of the adjustment were assessed by comparing coefficients of variation before and after correction, by correlation and regression between mean and standard deviations, and by using Gini coefficients and Lorenz curves. The adjustment procedure reduced heteroscedasticity primarily by decreasing the frequency of low-variance contemporary groups. Lorenz curves and Gini coefficients indicated that the largest impact of the standardization procedure was related to the size of the contemporary group. Some differences in the effect of the correction were found between recording schemes. The method for adjusting records is simple and easy to adapt to current genetic evaluation procedures.

Partial milking of cattle in smallholder herds on the Accra Plains: some factors affecting daily partial milk yield and milk composition

1992 ◽  
Vol 54 (1) ◽  
pp. 15-21 ◽  
Author(s):  
S. A. Okantah
Keyword(s):  
Milk Yield ◽  
Milk Composition ◽  
Dry Season ◽  
Sub Saharan Africa ◽  
Factors Affecting ◽  
Stage Of Lactation ◽  
Lactation Length ◽  
Sub Saharan ◽  
Quadratic Effects ◽  
Accra Plains

AbstractDaily partial milk yield of Sanga cows in 13 smallholder agropastoralist herds at two locations on the Accra Plains was recorded through monthly sampling. Estimates of mean daily partial milk yield and milk composition were computed from 1266 observations. The unadjusted mean daily partial milk yield was 875 (s.e. 11) g. The composition of milk: total solids (TS), fat (F) and solid-not-fat (SNF) were 131 (s.e. 14), 41 (s.e. 11) and 90 (s.e. 7) g/kg respectively. Least squares estimate of mean daily partial milk yield were 808·2 and 462·4 g with average s.e. of 41·8 for wet and dry season respectively. The wet and dry season differences in daily partial milk yield, TS and F were highly significant (P < 0·01). Seasonal difference in SNF was not significant.Herd difference in partial milk yield, TS, F and SNF were highly significant (P < 0·02). There were no significant effects of location on daily partial milk yield and SNF, although location effects on F and TS were significant (P < 0·05). The highest milk yield was observed in cows in third lactation and the lowest in cows in seventh lactation (P < 0·01). Daily partial milk yield peaked in the 3rd month of lactation. On average, lactation length was 210 to 240 days. Both linear and quadratic effects of stage of lactation were highly significant (P < 0·01). Lactation curve parameters for partially milked cows were also estimated. The implications of the results for milk production in sub-Saharan Africa were discussed.

Use of ordered logit model with time series data for determining the factors affecting the milk yield of Holstein Friesians

2019 ◽  
Author(s):  
Özge Akkuş ◽  
Volkan Sevinç
Keyword(s):  
Time Series ◽  
Milk Yield ◽  
Logit Model ◽  
Time Series Data ◽  
Series Data ◽  
Ordered Logit ◽  
Factors Affecting ◽  
Ordered Logit Model ◽  
Lactation Length ◽  
Cattle Breeders

This article aims to introduce the use of ordered logit model with time series data in milk productivity studies and determine the important factor levels affecting the milk yield of Holstein Friesians. The data consists of 2002 records collected for the years 2009-2015 from the reports of the Cattle Breeders’ Association of Turkey (CBAT) in Muðla province in Turkey. The direct and marginal effects of the variables: parity, lactation length and year of calving on milk yield are investigated and the probabilities regarding the milk yield production for a given specific parity, lactation length and calving year are calculated. The results show that milk yield slightly increases on the 4th parity of cows. As far as the years concerned, although there had mostly been a steady amount of milk production between 2009 and 2015 years, there was a significant decrease in 2011 and increase in 2014.

Some factors affecting milk yield

1923 ◽  
Vol 13 (1) ◽  
pp. 74-119 ◽  
Author(s):  
J. Hammond ◽  
H. G. Sanders
Keyword(s):  
Milk Yield ◽  
Maximum Yield ◽  
Dry Period ◽  
Factors Affecting ◽  
Live Stock ◽  
The Subject ◽  
The Mean

(1) The variation of the total yields according to the month of calving is given, and causes for this variation are suggested from the mean lactation curves of cows calving in each month.(2) A curve showing the effect of pregnancy on the lactation yield has been prepared and corrections are given for different lengths of service periods after calving—“100 days” being chosen as a standard, as that was found to be the average of all service periods obtained, and as it gives a calf at about the same time in the following year.(3) The variation in yield as the cow gets older has been studied and corrections are given. The maximum yield appears to be reached at the fifth calf; it was found that service periods varied in a definite way with age.(4) The effect of the dry period before calving on the subsequent yield is shown; “85 days” has been taken as a standard and corrections given accordingly; the standard was the mean of all dry periods obtained, but is probably above the average throughout the country.(5) By applying these corrections, the variation of individual totals is reduced by approximately 20 per cent, and the number of lactations showing less than 5 per cent, variation is increased by 27·3 per cent.(6) A brief review of other literature on the subject is given, and the results obtained in this paper are compared with those of other investigators.The thanks of the authors are due to the members of the Penrith Milk Recording Society for the loan of their registers, which made this investigation possible, and to Mr Garnet, the Live Stock Officer of the district, and the Live Stock Branch, of the Ministry of Agriculture and Fisheries for the collection of the data; the authors are also greatly indebted to Mr G. Udny Yule, M.A., F.R.S., for much assistance in the purely statistical part of the work, and to Dr F. H. A. Marshall, F.R.S., for his advice during the course of the investigation.

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