scholarly journals Random Regression Model for Genetic Evaluation and Early Selection in the Iranian Holstein Population

Animals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3492
Author(s):  
Yasamin Salimiyekta ◽  
Rasoul Vaez-Torshizi ◽  
Mokhtar Ali Abbasi ◽  
Nasser Emmamjome-Kashan ◽  
Mehdi Amin-Afshar ◽  
...  
Keyword(s):  
Milk Yield ◽  
Cross Validation ◽  
Early Selection ◽  
Random Regression ◽  
Likelihood Method ◽  
Early Lactation ◽  
Breeding Values ◽  
Daily Milk Yield ◽  
Holstein Population ◽  
Daily Milk

The objective of this study was to use a model to predict breeding values for sires and cows at an early stage of the first lactation of cows and progeny groups in the Iranian Holstein population to enable the early selection of sires. An additional objective was to estimate genetic and phenotypic parameters associated with this model. The accuracy of predicted breeding values was investigated using cross-validation based on sequential genetic evaluations emulating yearly evaluation runs. The data consisted of 2,166,925 test-day records from 456,712 cows calving between 1990 and 2015. (Co)-variance components and breeding values were estimated using a random regression test-day model and the average information (AI) restricted maximum likelihood method (REML). Legendre polynomial functions of order three were chosen to fit the additive genetic and permanent environmental effects, and a homogeneous residual variance was assumed throughout lactation. The lowest heritability of daily milk yield was estimated to be just under 0.14 in early lactation, and the highest heritability of daily milk yield was estimated to be 0.18 in mid-lactation. Cross-validation showed a highly positive correlation of predicted breeding values between consecutive yearly evaluations for both cows and sires. Correlation between predicted breeding values based only on records of early lactation (5–90 days) and records including late lactation (181–305 days) were 0.77–0.87 for cows and 0.81–0.94 for sires. These results show that we can select sires according to their daughters’ early lactation information before they finish the first lactation. This can be used to decrease generation interval and to increase genetic gain in the Iranian Holstein population.

Random regression animal models for genetic evaluation of test-day milk yield and milking duration in Saudi dairy goats

2018 ◽  
Author(s):  
A.A. Amin
Keyword(s):  
Milk Yield ◽  
Genetic Correlations ◽  
Random Regression ◽  
Dairy Goats ◽  
Data Set ◽  
Breeding Values ◽  
Sample Test ◽  
Early Production ◽  
Daily Milk Yield ◽  
Daily Milk

Random regression animal model was applied for analyzing the relationships between daily milk yield (MK) and milking duration (DR) in dairy goats comparing with reviewed estimates in dairy cows. The current analyzed data involved 17345 sample test-day records from multiparous Saudi dairy goats. A cubic random regression was applied for representing additive genetic variances in all studied traits across all different days in milk (12 groups). Based on multi-lactation random regression data-set analysis, the role of inheritance was greatest during the later stages of lactation. Heritability estimates of daily milk yield (h2MK) ranged from 0.15 to 0.54. While estimates of heritability for milking duration (h2DR) were very low during the first 60 days of lactation, being not more than 0.04. During the 2nd half of lactation the estimates of h2DR ranged from 0.35 to 0.39. Results of genetic variations for lactation records during early production life showed that highest milk harvest with intermediate milking rate could be achieved. Estimates of expected breeding values for milk yield and milking duration increased in different rates with progressing days in milk groups. These results indicated that individual selection results would be favorably achieved during the late part of lactation. Additive genetic correlations between measures of all traits at different lactation months continuously decreased as the interval between test days increased. Additive genetic correlations between milking duration and milk yield were positive and considerably high. Correlations between expected breeding values of both traits ranged from 0.41 to 0.83 (mean = 0.69) across different lactation months. More details on estimates of breeding values, estimates of permanent environmental and additive genetic correlations for all traits were tabulated.

scholarly journals Genetic parameters for milk yield in imported Jersey and Jersey-Friesian cows using daily milk records in Sri Lanka

2020 ◽  
Vol 33 (11) ◽  
pp. 1741-1754
Author(s):  
Amali Malshani Samaraweera ◽  
Vinzent Boerner ◽  
Hewa Waduge Cyril ◽  
Julius van der Werf ◽  
Susanne Hermesch
Keyword(s):  
Sri Lanka ◽  
Animal Models ◽  
Milk Yield ◽  
Genetic Parameters ◽  
Random Regression ◽  
Breeding Values ◽  
Daily Milk Yield ◽  
Jersey Cows ◽  
Daily Milk ◽  
Friesian Cows

Objective: This study was conducted to estimate genetic parameters for milk yield traits using daily milk yield records from parlour data generated in an intensively managed commercial dairy farm with Jersey and Jersey-Friesian cows in Sri Lanka.Methods: Genetic parameters were estimated for first and second lactation predicted and realized 305-day milk yield using univariate animal models. Genetic parameters were also estimated for total milk yield for each 30-day intervals of the first lactation using univariate animal models and for daily milk yield using random regression models fitting second-order Legendre polynomials and assuming heterogeneous residual variances. Breeding values for predicted 305-day milk yield were estimated using an animal model.Results: For the first lactation, the heritability of predicted 305-day milk yield in Jersey cows (0.08±0.03) was higher than that of Jersey-Friesian cows (0.02±0.01). The second lactation heritability estimates were similar to that of first lactation. The repeatability of the daily milk records was 0.28±0.01 and the heritability ranged from 0.002±0.05 to 0.19±0.02 depending on day of milk. Pearson product-moment correlations between the bull estimated breeding values (EBVs) in Australia and bull EBVs in Sri Lanka for 305-day milk yield were 0.39 in Jersey cows and –0.35 in Jersey-Friesian cows.Conclusion: The heritabilities estimated for milk yield in Jersey and Jersey-Friesian cows in Sri Lanka were low, and were associated with low additive genetic variances for the traits. Sire differences in Australia were not expressed in the tropical low-country of Sri Lanka. Therefore, genetic progress achieved by importing genetic material from Australia can be expected to be slow. This emphasizes the need for a within-country evaluation of bulls to produce locally adapted dairy cows.

Milk acetone concentration as an indicator of hyperketonaemia in dairy cows: the critical value revised

1996 ◽  
Vol 63 (2) ◽  
pp. 183-188 ◽  
Author(s):  
A. H. Gustafsson ◽  
U. Emanuelson
Keyword(s):  
Dairy Cows ◽  
Milk Yield ◽  
Critical Value ◽  
Critical Values ◽  
Reproductive Efficiency ◽  
Early Lactation ◽  
Acetone Concentration ◽  
Daily Milk Yield ◽  
Daily Milk

AbstractAcetone concentration in milk is correlated with subclinical and clinical ketosis and also with milk yield and reproductive efficiency. The purpose of this study was to assess a threshold of milk acetone at which cows tend to be adversely affected. The critical values were estimated on data from 11690 lactations where the change in daily milk yield from weeks 1 to 2 to weeks 5 to 6 of lactation was evaluated in relation to different milk acetone concentrations. Daily milk yield tended to be reduced in cows with acetone concentrations between 0·7 and 1·4 mmol/l, but responses were not entirely consistent. At concentrations >l·4 mmol/l, daily milk yield was clearly reduced. Long-term milk yield (day 0 to 100 and day 0 to 200) was about 190 kg of 40 g/kg fat-corrected milk (FCM) less in cows with acetone concentrations >l·4 vis-à-vis <0·7 mmol/l. Reproductive efficiency was also impaired in cows with acetone concentrations >l·4 mmol/l; 4·9 days longer interval from calving to first service (first parity and parity 2+ cows) and 5·7 times a greater risk of cystic ovaries (parity 1), compared with cows with milk acetone <0·7 mmol/l. However, no significant effects on long-term milk yield or on reproductive efficiency were found in cows with acetone concentrations 0·7 to 1·4 vis-à-vis <0·7 mmol/l. The results suggest that 1·4 mmol/l acetone in milk may be used as the most important critical value, as higher concentrations are detrimental to productivity. The interval 0·7 to 1·4 mmol acetone per I milk may be used as a warning class, since early lactation yield may be reduced.

Economic potential of individual variation in milk yield response to concentrate intake of dairy cows

2010 ◽  
Vol 148 (3) ◽  
pp. 263-276 ◽  
Author(s):  
G. ANDRÉ ◽  
P. B. M. BERENTSEN ◽  
G. VAN DUINKERKEN ◽  
B. ENGEL ◽  
A. G. J. M. OUDE LANSINK
Keyword(s):  
Observational Study ◽  
Milk Yield ◽  
Individual Variation ◽  
Study Data ◽  
Yield Response ◽  
Individual Response ◽  
Early Lactation ◽  
The Individual ◽  
Daily Milk Yield ◽  
Daily Milk

SUMMARYThe objectives of the current study were to quantify the individual variation in daily milk yield response to concentrate intake during early lactation and to assess the economic prospects of exploiting the individual variation in milk yield response to concentrate intake. In an observational study, data from 299 cows on four farms in the first 3 weeks of the lactation were collected. Individual response in daily milk yield to concentrate intake was analysed by a random coefficient model. Marked variation in individual milk yield response to concentrate intake was found on all four farms. An economic simulation was carried out, based on the estimated parameter values in the observational study. Individual optimization of concentrate supply is compared with conventional strategies for concentrate supply based on averaged population response parameters. Applying individual economic optimal settings for concentrate supply during early lactation, potential economic gain ranges from €0·20 to €2·03/cow/day.

Efficacy of a lasalocid supplement in the diet of dairy cows in early lactation in a pasture-based dairy system

2007 ◽  
Vol 47 (6) ◽  
pp. 658 ◽  
Author(s):  
C. R. Stockdale
Keyword(s):  
Dairy Cows ◽  
Milk Yield ◽  
Control Group ◽  
Early Lactation ◽  
Maize Silage ◽  
Production History ◽  
Equivalent Control ◽  
Yield Responses ◽  
Daily Milk Yield ◽  
Daily Milk

The lasalocid supplement, Bovatec, was fed to dairy cows at 300 mg of active ingredient for ~3 weeks precalving to up to 16 weeks postcalving in a pasture-based system. Sixty primiparous cows and 120 multiparous cows were allocated to equivalent control and lasalocid groups based on expected calving date, size and previous production history. To facilitate the feeding of the lasalocid, it was mixed with maize silage (~1 kg DM/cow.day) and fed as one feed on a concrete feed pad early in the morning each day before calving and before the afternoon milking during lactation. The control group received the maize silage without lasalocid. Otherwise, the feeding of both groups was exactly the same. The key response associated with adding lasalocid to the diet differed between the primiparous and multiparous cows. Although the average daily milk yield responses to lasalocid were not significant (P > 0.05) at 1.1 and 0.6 kg/cow for the primiparous and multiparous cows, respectively, significant (P < 0.05) increases in the milk yield of the primiparous cows were consistently recorded between weeks 5 and 15 of lactation. With the multiparous cows, there was a significant (P < 0.05) decrease in the circulating concentrations of serum β-hydroxybutyrate in those fed the lasalocid, with this being related to a tendency (P = 0.087) for these animals to maintain higher body condition scores for much of the early lactation treatment period. There were no other treatment differences of biological importance.

scholarly journals Estimation of genetic parameters and prediction of breeding values for some economic traits of Black Bengal Goat under farming condition

2020 ◽  
Vol 20 (1-2) ◽  
pp. 8-17
Author(s):  
MA Jalil ◽  
S Akther ◽  
MP Choudhury ◽  
MA Habib
Keyword(s):  
Birth Weight ◽  
Litter Size ◽  
Milk Yield ◽  
Genetic Parameters ◽  
Breeding Values ◽  
Lactation Length ◽  
Total Milk ◽  
Daily Milk Yield ◽  
Black Bengal Goat ◽  
Daily Milk

The study was undertaken to evaluate the genetic progress of Black Bengal Goat (BBG) by estimating genetic parameters viz. heritability and breeding values for economically important productive and reproductive traits (birth weight, weight at 3, 6, 9 & 12 months, daily milk yield, lactation length, total milk yield and litter size of BBG goat population). Variance and co-variance components were analyzed applying Residual Maximum Likelihood (REML) approach by VCE 4.2.5 computer package. The heritability (h2) of birth weight was estimated as 0.2, which was low. The heritability estimates for 3-month weight (0.40), 6-month weight (0.50), 9-month weight (0.37) and 12-month weight (0.36) were found medium. Estimated h2 of daily milk yield, total milk yield and lactation length in this study were from 0.55 to 0.82.  h2 of litter size was 0.09. The maximum estimated breeding value (EBV) was found for 6 month body weight (12.94 kg), however, for daily milk yield, the value was 1.513 kg. The results found in this study revealed that genetic improvement of BBG for most of the traits is possible by selection and breeding. Bangladesh J. of Livestock Res. 20(1-2): 8-17, Jan-Dec 2013

scholarly journals Genetic and permanent environmental variations in daily milk yield and milk flow rates in Hungarian Holstein Friesian

2007 ◽  
Vol 50 (6) ◽  
pp. 535-548
Author(s):  
A. A. Amin
Keyword(s):  
Milk Yield ◽  
Genetic Correlations ◽  
Random Regression ◽  
Lactation Performance ◽  
Flow Rates ◽  
Breeding Values ◽  
Milk Flow ◽  
Holstein Friesian ◽  
Estimated Breeding Values ◽  
Daily Milk Yield

Abstract. Random regression animal model was applied for analyzing the relationships between test-day milk yields (DY), and milk flow rate (FR). The current study involved 169,491 sample test-day records of Hungarian Holstein- Friesian cows. A quadratic random regression was applied for declaring additive genetic variances in all studied traits during biweekly observations across the first three parities. Estimates of heritability for test-day milk yield and udder milk flow rates ranged from 0.09 to 0.58 and from 0.02 to 0.50, respectively through 42 milk-weeks (Wk). The highest heritability estimates occurred during the end of trajectory for both traits. In general DY tended to be more heritable than FR across lactation except during the first few weeks of lactation. Performance of DY was less affected by environmental variation than FR, while both values were moderate to high (0.63 to 0.75). Correlations among measurements showed that additive correlations (Ra) of 4WkFR with the reminder part of lactation were high during early and late lactation. Also 24WkFR was more genetically correlated with next measures and reached Ra = 0.94. Whereas 42WkFR was high additively correlated with other biweekly measurements and ranged from 0.53 to 0.99. Performance of early and late DY was negative additively correlated and ranged from −0.03 to −0.53. Heritability of DY within levels of FR ranged from 0.09 to 0.33 within very slow and medium milk flow, respectively. Correlations among both traits increased linearly toward lactation end. DY during 24Week and 42Week of lactation accounted the highest additive correlations with FR across lactation. Estimated breeding values for DY and FR increased in different rates with progressing lactation. These results may indicate that individual selection results would be favorably achieved during the late part of lactation. More details about estimates of breeding values, estimates of permanent environmental and additive genetic correlations for all traits were tabulated.

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