Genetic parameters for milk yield and litter size in Boutsico dairy sheep

1998 ◽  
Vol 78 (4) ◽  
pp. 525-532 ◽  
Author(s):  
A. Kominakis ◽  
E. Rogdakis ◽  
K. Koutsotolis
Keyword(s):  
Litter Size ◽  
Milk Yield ◽  
Raw Milk ◽  
Dairy Sheep ◽  
Genetic Covariance ◽  
Yield Data ◽  
Environmental Variance ◽  
Sheep Milk ◽  
Genetic And Phenotypic Correlations ◽  
Additive Genetic Effects

Lactation and litter size records (n = 2553) of Boutsico dairy sheep were used to estimate direct additive, maternal genetic, maternal and animal's permanent environmental variance components for milk yield and litter size by restricted maximum likelihood under a repeated records animal model. Raw milk yield data were transformed by log and Box–Cox (BC) transformations. Heritability estimates of direct additive effects were between 0.21 and 0.30, 0.18 and 0.24 and 0.21 and 0.27 for untransformed, log transformed and BC transformed data, respectively. Only maternal and animal's environmental effects were important for milk yield. Direct-maternal genetic covariance did not significantly (P > 0.05) influence milk yield. Repeatability for milk yield ranged from 0.32 to 0.38. Only additive genetic effects were important for litter size. Heritability and repeatability for litter size were 0.07 and 0.11, respectively. Genetic and phenotypic correlations between yield and litter size were 0.13 and 0.19, respectively. Key words: Sheep, milk yield, litter size, heritability, correlation

scholarly journals Covariance components by a repeatability model in Slovenian dairy sheep using test-day records

2009 ◽  
Vol 54 (No. 9) ◽  
pp. 426-434 ◽  
Author(s):  
A. Komprej ◽  
G. Gorjanc ◽  
D. Kon ◽  
M. Kovač
Keyword(s):  
Protein Content ◽  
Litter Size ◽  
Milk Yield ◽  
Genetic Correlations ◽  
Dairy Sheep ◽  
Milk Traits ◽  
Environment Effect ◽  
Covariance Components ◽  
Daily Milk Yield ◽  
Daily Milk

The estimation of covariance components for daily milk yield, fat and protein content was performed in three Slovenian dairy sheep breeds (Bovec, Improved Bovec, and Istrian Pramenka). In the period 1994–2002, 38 983 test-day records of 3 068 ewes were collected according to ICAR regulations (method A4). All the available relationships between animals were considered. For that reason, information on 3 534 animals was included. Test-day records were analysed by a multiple-trait repeatability animal model. In its fixed part, the model contained breed and season of lambing as classes. Days after lambing, parity, and litter size were treated as covariates. Days after lambing were modelled with modified Ali-Schaeffer’s lactation curve, parity with quadratic, and litter size with linear regression. The random part of the model consisted of flock-test month effect, additive genetic effect, permanent environment effect over lactations, and permanent environment effect within lactation. Covariance components were estimated using the restricted maximum likelihood method (REML). The estimated heritabilities were 0.11 for daily milk yield, 0.08 for fat content, and 0.10 for protein content. A relatively high variance ratio for all milk traits was explained by the flock-test month effect (from 0.27 for daily milk yield to 0.57 for protein content), while ratios explained by both permanent environment effects were lower (up to 0.13). Additive genetic correlations between daily milk yield and fat content, and daily milk yield and protein content were negative and similar (–0.36 and –0.37). A high and positive (0.67) additive genetic correlation between fat and protein content was found. Correlations for environmental effects showed a pattern similar to additive genetic correlations. Genetic parameters estimated in Slovenian dairy sheep showed that genetic progress in milk traits could be achieved using test-day milk records.

scholarly journals Industrial chemical bisphenol A and raw milk: a toxicokinetic study in lactating dairy sheep after repeated dietary and subcutaneous administration

2019 ◽  
Author(s):  
Sabina Šturm ◽  
Andrej Škibin ◽  
Iztok Grabnar ◽  
Milan Pogačnik ◽  
Vesna Cerkvenik Flajs
Keyword(s):  
Bisphenol A ◽  
Human Exposure ◽  
Low Dose ◽  
Animal Feed ◽  
Subcutaneous Administration ◽  
Raw Milk ◽  
Dairy Sheep ◽  
Food Items ◽  
Sheep Milk ◽  
Toxicokinetic Model

Abstract • Background: Dietary intake is the predominant route for human exposure to bisphenol A and one of the food items important for humans is milk, and BPA-polluted animal feed and environments may thus affect human exposure. The aim of our study was to evaluate the BPA exposure and disposition in sheep milk after repeated dietary and subcutaneous administration of a relatively low dose (100 µg/kg of body weight per day) of BPA to a sheep. • Results: With our toxicokinetic model, we showed that most likely only free BPA passes into the mammary gland and is subsequently conjugated there. The percentage of the dose eliminated with milk was less than 0.1%, regardless of the route of BPA administration. • Conclusions: It is proven that the BPA is eliminated through the milk of lactating sheep. However, the amounts excreted in the milk that were detected in this study are minimal.

scholarly journals  Lactation curves for milk yield, fat and protein content in Slovenian dairy sheep

2012 ◽  
Vol 57 (No. 5) ◽  
pp. 231-239 ◽  
Author(s):  
A. Komprej ◽  
G. Gorjanc ◽  
D. Kon ◽  
M. Kovač
Keyword(s):  
Animal Model ◽  
Protein Content ◽  
Litter Size ◽  
Milk Yield ◽  
Additive Genetic Effect ◽  
Dairy Sheep ◽  
Stage Of Lactation ◽  
Lactation Curve ◽  
Daily Milk Yield ◽  
Daily Milk

Lactation curves for daily milk yield, fat, and protein content in three dairy sheep breeds were estimated by the repeatability animal model using test-day records. A total of 38 983 records from 3068 ewes of Bovec, Improved Bovec, and Istrian Pramenka breeds, collected between the years 1994 and 2002, were analysed. The three-trait repeatability animal model included breed and lambing season as fixed. The stage of lactation within each breed was modelled by the modified Ali-Schaeffer’s lactation curve. Parity and litter size were used as covariates in quadratic and linear regression, respectively. Common flock environment, additive genetic effect, permanent environment over lactations as well as within lactation were treated as random. The average daily milk yield was 1090 g in Bovec, 1010 g in Improved Bovec, and 731 g in Istrian Pramenka breeds. Overall means for fat and protein content were 6.59 and 5.53% for Bovec, 6.22 and 5.33% for Improved Bovec, and 7.20 and 5.63% for Istrian Pramenka. Breed, lambing season, stage of lactation, parity, and litter size significantly (P < 0.001) affected all three observed milk traits, with the only exception of parity in fat and litter size in protein content. The shape of lactation curves for daily milk yield in Bovec and Improved Bovec breeds fitted well to the general lactation curve in dairy sheep. Daily milk yield was increasing in the first month of lactation and decreasing thereafter. In Istrian Pramenka, the shape of lactation curve was more or less atypical, with daily milk yield decreasing almost throughout the entire lactation. Lactation curves for fat and protein content were opposite to the lactation curves for daily milk yield in all three breeds.  

scholarly journals Changes in Native Whey Protein Content, Gel Formation, and Endogenous Enzyme Activities Induced by Flow-Through Heat Treatments of Goat and Sheep Milk

Dairy ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 410-421
Author(s):  
Golfo Moatsou ◽  
Ekaterini Moschopoulou ◽  
Evangelia Zoidou ◽  
Aggeliki Kamvysi ◽  
Dimitra Liaskou ◽  
...  
Keyword(s):  
Whey Protein ◽  
Enzyme Activities ◽  
Goat Milk ◽  
Raw Milk ◽  
Heat Treatments ◽  
Clotting Time ◽  
Sheep Milk ◽  
Native Whey ◽  
Flow Through ◽  
Water Holding

The aim of the present study was to assess the effects of different flow-through heat treatments—68, 73, 78, 85, 100 °C for 16 s—applied to in-line homogenized goat and sheep milk. Alkaline phosphatase (ALP) activity in raw goat milk was 324.5 ± 47.3 μg phenol/mL, and that of lactoperoxidase (LPO) was 199.3 ± 6.7 U/L. The respective activities in raw sheep milk were 7615 ± 141 μg phenol/mL and 319 ± 38.6 U/L. LPO activity was not detected in both milk kinds treated at 85 °C for 16 s. Residual enzyme activities at 73 °C for 16 s with respect to the initial levels in raw milk were higher in goat than in sheep milk. The whey protein fraction of sheep milk was more heat sensitive compared to goat counterpart. Sheep milk rennet clotting time (RCT) was not affected by the treatments, while curd firmness decreased significantly (p < 0.05) at 100 °C for 16 s. Treatments more intense than 73 °C for 16 s increased the RCT of goat milk significantly but inconsistently and decreased curd firmness significantly, while yoghurt-type gels made from 73 °C or 78 °C for 16 s treated goat milk exhibited the highest water-holding capacity.

NEURAL FACTORS IN THE MAINTENANCE OF LACTATION IN THE RAT

1967 ◽  
Vol 38 (1) ◽  
pp. 51-59 ◽  
Author(s):  
J. A. EDWARDSON ◽  
J. T. EAYRS
Keyword(s):  
Litter Size ◽  
Milk Yield ◽  
Quantitative Relationship ◽  
Mammary Tissue ◽  
Single Pair ◽  
Endocrine Response ◽  
Peripheral Innervation ◽  
Lactational Performance ◽  
Neural Factors

SUMMARY The role of the peripheral innervation of mammary tissue in the maintenance of lactation has been investigated by the procedure of selective thelectomy combined with denervation of the posterior thoracic nipples. When suckling is restricted to a single pair of nipples bilateral transection of the three adjacent nerves supplying a nipple arrests lactation completely; partial denervation is associated with a reduced level of lactational performance which is directly related to the concentration of the residual innervation. Increase in litter size is associated with an overall increase in milk-yield up to a limit beyond which the addition of further young to the litter is without effect. It is inferred that there is a quantitative relationship between the neural stimulus of suckling and the endocrine response of the hypothalamopituitary system.

scholarly journals Genetic Parameters for First Lactation and Lifetime Traits of Nili-Ravi Buffaloes

2021 ◽  
Vol 8 ◽  
Author(s):  
Pooja Tamboli ◽  
Anurag Bharadwaj ◽  
Amit Chaurasiya ◽  
Yogesh Chandrakant Bangar ◽  
Andonissamy Jerome
Keyword(s):  
Genetic Correlation ◽  
Milk Yield ◽  
Phenotypic Correlation ◽  
Productive Life ◽  
Lactation Length ◽  
Service Period ◽  
Reproduction Traits ◽  
Genetic And Phenotypic Correlations ◽  
Breeding Efficiency ◽  
Estimation Of Variance

The data on first lactation and lifetime performance records of 501 Nili-Ravi were collected for a period from 1983 to 2017 (35 years) maintained at ICAR-Central Institute for Research on Buffaloes, Sub-Campus, Nabha, Punjab. The data were analyzed to calculate heritability, genetic and phenotypic correlation for first lactation traits, viz., Age at First Calving (AFC), First Lactation Total Milk Yield (FLTMY), First Lactation Standard (305 days or less) Milk Yield (FLSMY), First Peak Milk Yield (FPY), First Lactation Length (FLL), First Dry Period (FDP), First Service Period (FSP) and First Calving Interval (FCI), Herd Life (HL), Productive Life (PL), Productive Days (PD), Unproductive Days (UD), Breeding Efficiency (BE), Total Lifetime Milk Yield (Total LTMY), Standard Lifetime Milk Yield (Standard LTMY), Milk Yield Per Day of Productive Life (MY/PL), Milk Yield Per Day of Productive Days (MY/PD), and Milk Yield Per Day of Herd Life (MY/HL). For estimation of variance component and heritability separately for each trait, the uni-trait animal model was equipped, whereas to estimate genetic and phenotypic correlations between traits, bi-trait animal models were fitted. The estimates of heritability for production and reproduction traits of Nili-Ravi were medium, i.e., 0.365 ± 0.087, 0.353 ± 0.071, 0.318 ± 0.082, 0.354 ± 0.076, and 0.362 ± 0.086 for FLSMY, FDP, FSP, FCI, and AFC, respectively. The estimates of heritability were low, i.e., 0.062 ± 0.088, 0.123 ± 0.090, 0.158 ± 0.090, 0.155 ± 0.091, and 0.129 ± 0.091 for HL, PL, PD, Total LTMY, and Standard LTMY and high, i.e., 0.669 ± 0.096 for BE. Genetic correlation for FLTMY was high with FLL (0.710 ± 0.103), and genetic correlation of FLTMY was high and positive with HL, Total LTMY, MY/PL, and MY/PD while low and positive with PL. Genetic correlation of AFC was low and negative with PL, PD, UD, BE, Total LTMY, Standard LTMY, MY/PL, and MY/PD and negative with MY/HL. Significant positive phenotypic association of FPY was seen with FLTMY, FLSMY, FLL, AFC, HL, Total LTMY, and Standard LTMY. Higher heritability of first lactation traits especially FPY suggests sufficient additive genetic variability, which can be exploited under selection and breeding policy in order to improve overall performance of Nili-Ravi buffaloes.

scholarly journals Effects of month of kidding, parity number, and litter size on milk yield of commercial dairy goats in Australia

2020 ◽  
Vol 103 (1) ◽  
pp. 954-964 ◽  
Author(s):  
F. Zamuner ◽  
K. DiGiacomo ◽  
A.W.N. Cameron ◽  
B.J. Leury
Keyword(s):  
Litter Size ◽  
Milk Yield ◽  
Dairy Goats ◽  
Parity Number

scholarly journals Milk Production of Lacaune Sheep with Different Degrees of Crossing with Manchega Sheep in a Commercial Flock in Spain

Animals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 520
Author(s):  
Lizbeth E. Robles Jimenez ◽  
Juan C. Angeles Hernandez ◽  
Carlos Palacios ◽  
José A. Abecia ◽  
Anna Naranjo ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Milk Production ◽  
Litter Size ◽  
Milk Yield ◽  
Mixed Model ◽  
The Other ◽  
Commercial Flock ◽  
Parity Number ◽  
Available Information ◽  
Autumn And Winter

The objective of the present study was to evaluate the effect of the grade of crossbreeding (Lacaune x Manchega) and environmental factors on milk production in a commercial flock in Spain. A total of 5769 milk production records of sheep with different degrees of purity of the Lacaune breed crossed with Manchega were used as follows: 100% Lacaune (n = 2960), 7/8 Lacaune (n = 502), 13/16 Lacaune (n = 306), 3/4 (n = 1288), 5/8 Lacaune (n = 441) and 1/2 Lacaune: Manchega (n = 272). Additional available information included the number of parity (1 to 8), litter size (single or multiple), and the season of the year of lambing (spring, summer, autumn and winter). A mixed model was used to evaluate the level of crossbreeding and environmental factors on milk production. The 100% Lacaune sheep presented the highest milk production with respect to the F1 Lacaune x Manchega sheep (p < 0.01), showing that as the degree of gene absorption increases with the Manchega breed, it presents lower milk yield. The 100%, 13/16, and 3/4 Lacaune genotypes had the highest milk yields with respect to the 1/2 Lacaune/Manchega breed (p < 0.001). The Lacaune registered on average 181.1 L in a period adjusted to 160 days of lactation (1.13 L/ day). Likewise, the parity number, litter size, and season of lambing effects showed significant differences (p < 0.01). It was concluded that 13/16 and 3/4 Lacaune/Manchega ewes presented the highest milk yields with respect to the other crosses.

scholarly journals Milk production and lactation length in Ankole cattle and Ankole crossbreds in Rwanda

2020 ◽  
Vol 52 (6) ◽  
pp. 2937-2943
Author(s):  
Maximillian Manzi ◽  
Lotta Rydhmer ◽  
Martin Ntawubizi ◽  
Claire D’Andre Hirwa ◽  
Callixte Karege ◽  
...  
Keyword(s):  
Milk Production ◽  
Milk Yield ◽  
Mixed Linear Model ◽  
Yield Data ◽  
Ankole Cattle ◽  
Lactation Length ◽  
Breed Group ◽  
Significant Difference ◽  
Daily Milk Yield ◽  
Daily Milk

Abstract This study assessed daily milk yield (DMY), 100-day (MY100), and 305-day (MY305) milk yield, and lactation length (LL) in purebred Ankole cattle and Ankole crossbreds, and the influence of environmental factors on these traits. Milk yield data were obtained for 865 cows and 1234 lactations and analyzed using a mixed linear model. The overall least squares mean of DMY, MY100, and MY305 across breed groups was 2.7 L (N = 1234, SD = 1.7), 262 L (N = 959, SD = 176), and 759 L (N = 448, SD = 439), respectively, while the average lactation length was 256 days (N = 960, SD = 122). All factors included (breed group, season and year of calving, and parity) were significant for yield traits, except season of calving for MY305. First-parity cows had the lowest milk production, and fourth-parity cows the highest. For all traits, pure Ankole cows had the lowest milk yield. Among the crossbreds, there was no significant difference between Ankole × Friesian, Ankole-Jersey mother × Sahiwal sire, and Ankole-Sahiwal mother × Jersey sire, or between Ankole × Sahiwal and Ankole-Sahiwal mother × Sahiwal sire. It was concluded that Ankole crosses with Friesian or Jersey can be beneficial, even under a management system of limited nutrition as in Rwanda.

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