scholarly journals Effect of Age at First Calving on Production Traits and on Difference Between Milk Yield Returns and Rearing Costs in Italian Holsteins

2000 ◽  
Vol 83 (3) ◽  
pp. 603-608 ◽  
Author(s):  
G. Pirlo ◽  
F. Miglior ◽  
M. Speroni
Keyword(s):  
Milk Yield ◽  
Production Traits ◽  
Age At First Calving ◽  
Effect Of Age

Effect of age at first calving and other non-genetic factors on longevity and production traits in Holstein cattle under Vojvodina Province condition, Serbia

2019 ◽  
Author(s):  
D. Kuèeviæ ◽  
S. Dragin ◽  
I. Pihler ◽  
K. Èobanoviæ ◽  
T. Papoviæ ◽  
...  
Keyword(s):  
Milk Yield ◽  
Genetic Factors ◽  
Fixed Effect Model ◽  
Production Traits ◽  
Age At First Calving ◽  
Effect Model ◽  
Calving Season ◽  
Novi Sad ◽  
Effect Of Age ◽  
Vojvodina Province

The effect of age at first calving (AFC) and various non-genetic factors i.e. season of calving, farm and system of housing on longevity and production traits were investigated. Longevity traits were studied using total lifetime (TL), length of productive life (LPL) and number of lactations (NL) while production was researched using lifetime milk yield (LMY). Data of 2037 Holstein dairy cows were provided by the main breeding organizations at the Faculty of Agriculture, University of Novi Sad. The average values and variability of examined traits as well as the effect of factors on longevity and production traits were investigated using fixed effect model by general linear model (GLM) procedure in software package Statistica 13. Results showed highly significant effect of the AFC, calving season and farm, on all studied longevity traits (P less than 0.01), while non- significant effect was expressed on lifetime milk yield (P greater than 0.05). The mean of AFC, TL, LPL, NL and LMY for Holstein cows were 27.3, 67.5, 40.2 months, 2.45 and 18798.0 kg, respectively. The maximum values of LPL, NL and LMY were noticed for cows with age at first calving before 23 months of age. The LPL ranged from 47.88 (AFC less than 23 m) to 35.84 m (AFC>29 m) and declined progressively when the AFC is increased, particularly in cows calving at more than 29 m.

scholarly journals Effect of Age at First Calving on First Lactation Milk Yield in Holstein Cows from Costa Rican Specialized Dairy Herds

2014 ◽  
Vol 04 (09) ◽  
pp. 197-203
Author(s):  
Mauren Salazar-Carranza ◽  
Gloriana Castillo-Badilla ◽  
Jaime Murillo-Herrera ◽  
Frank Hueckmann-Voss ◽  
Juan José Romero-Zúñiga
Keyword(s):  
Milk Yield ◽  
Costa Rican ◽  
Holstein Cows ◽  
Dairy Herds ◽  
Age At First Calving ◽  
Effect Of Age

scholarly journals Effect of Age at First Calving on First Lactation Milk Yield, Lifetime Milk Production And Longevity of Cows

2019 ◽  
Vol 19 (1) ◽  
pp. 189-200
Author(s):  
Anna Sawa ◽  
Kamil Siatka ◽  
Sylwia Krężel-Czopek
Keyword(s):  
Dairy Cows ◽  
Milk Production ◽  
Milk Yield ◽  
Considerable Decrease ◽  
Age At First Calving ◽  
Productive Life ◽  
Active Population ◽  
Holstein Friesian ◽  
Effect Of Age ◽  
Friesian Cows

AbstractThe objective of the study was to analyse the effect of age at first calving (AFC) on first lactation milk yield, lifetime milk production and longevity of dairy cows. The study used SYMLEK data on the milk yield and culling of 111 857 Polish Holstein-Friesian cows from the active population in Pomerania and Kujawy, Poland. The cows first calved during 2000–2009 and were used or removed from the herds until the end of 2015. For each cow, calculations were made of first lactation milk yield, lifetime milk production, first lactation milk yield per milking day, lifetime milk production per day, as well as the lifespan (length of productive life, duration of rearing) and number of calvings. Based on the age at first calving (duration of the rearing period), the cows were grouped as follows: ≤22, 22.1–24.0, 24.1–26.0, 26.1–28.0, 28.1–30.0, 30.1–32.0 and >32 months. The GLM, CORR PEARSON and FREQ procedures from the SAS package were used in the statistical calculations. Considering first lactation milk yield, lifetime milk production and longevity, it is recommended that the cows should be first milked between 22.1 and 26.0 months of age. This is supported by the approximately 24% higher lifetime milk production in relation to the latest calving cows (P<0.01). Late commencement of the first milking (especially after 28 months) causes a considerable decrease in the first lactation milk yield and lifetime milk production, shortens the productive period, reduces the number of calvings, and increases culling rate due to low milk yield and udder diseases.

scholarly journals The effect of age at first calving on the milking performance of primiparous Jersey cows

2021 ◽  
Vol 17 (1) ◽  
pp. 1-10
Author(s):  
Jarosław Pytlewski ◽  
Ireneusz Ryszard Antkowiak
Keyword(s):  
Milk Yield ◽  
Age At First Calving ◽  
Exact Test ◽  
Lactation Curve ◽  
Younger Age ◽  
Daily Milk Yield ◽  
Linear Graphs ◽  
Jersey Cows ◽  
Effect Of Age ◽  
Daily Milk

<b>The aim of this study was to determine the effect of age at first calving on the milking performance of primiparous Jersey cows (261 cows). Analyses were conducted on 2461 test day milking samples from 17.09.2007 to 26.07.2016. The primiparous cows were divided into four groups according to their age at first calving (≤ 24, > 24–26, > 26–28, > 28 months), and their daily milk yields were compared. Fourfold contingency tables were prepared to investigate the distribution of the population of cows calving at different ages and the peak daily milk yield. The significance of the association between factors was estimated using Fisher's exact test. To illustrate the course of 305-day lactation in primiparous cows varying in age at first calving, linear graphs were plotted with linear trends for daily milk yields. Primiparous Jersey cows calving at the age of > 26–28 months of life had the highest daily milk yield. In terms of the contents of basic milk constituents in the first lactation, the most advantageous age at first calving was > 24–26 months of life. However, a younger age at first calving (≤ 24 months) was associated with a lower somatic cell count in milk as well as a more favourable lactation curve for daily milk yield. The results of the study may suggest that Jersey cows calving at an earlier age (up to 24 months) may have a longer productive life and thus better performance parameters.

EFFICIENCY AND COMPARISON OF THE TEST-DAY MODEL AND BLUP METHOD MODIFICATIONS FOR ASSESSING BULLS BREEDING VALUE IN SIMMENTAL CATTLE BREED

2020 ◽  
Author(s):  
А.И. МАМОНТОВА ◽  
С.А. НИКИТИН ◽  
Е.Е. МЕЛЬНИКОВА ◽  
А.А. СЕРМЯГИН
Keyword(s):  
Animal Model ◽  
Milk Yield ◽  
Cattle Breed ◽  
Breeding Value ◽  
Am1 Method ◽  
Production Traits ◽  
Genetic Trend ◽  
Sire Model ◽  
The Russian Federation ◽  
Simmental Cattle

Целью проведенных исследований являлась отработка и адаптация применения методик BLUP AM (Animal Model — модель животного) и TDM (Test-Day Model — модель тестового дня) для прогнозирования племенной ценности быков-производителей и оценки селекционно-генетических параметров на популяции скота симментальской породы четырех регионов РФ. Проведен сравнительный анализ указанных методов с более ранним методом BLUP SM (Sire Model — модель отца). Рассчитана племенная ценность быков и коров симментальской породы по признакам молочной продуктивности: удой за 305 дней, выход молочного жира, выход молочного белка. Анализ полученных средних значений достоверности оценок быков-производителей, рассчитанных на основе сопоставляемых методов, свидетельствует, что достоверность для признака «удой за 305 дней» при переходе от метода SM1 к AM1 увеличивается на 2,4%, а при переходе от SM1 к TDM1 — на 7,8%. Даны варианты генетического тренда по удою с использованием различных уравнений моделей расчета племенной ценности. На основании полученных данных можно сделать вывод о том, что модель тестового дня позволяет не только повысить точность оценок быков, но и более рельефно выявить их ранги, а также несколько уменьшить срок получения достоверных оценок производителей по качеству потомства по продуктивным признакам. The purpose of this research was to develop and adapt the application of BLUP AM (Animal Model) and TDM (Test-Day Model) methods for predicting the sires breeding value and evaluating genetic parameters for Simmental cattle population in four regions of the Russian Federation. A comparative analysis of these methods with the earlier BLUP SM (Sire Model) method is performed. The breeding value for sires and cows of Simmental breed was calculated by milk production traits: milk yield for 305 days; milk fatyield; milk proteinyield. The sires reliability of average breeding value calculated by different methods reveal that milk yield for 305 days when switching from the SM1 to AM1 method increases by 2.4%, and when switching from SM1 to TDM1 — by 7.8%.The variants of the genetic trend for milk yield are given using various equations of BLUP and TDM. Based on the obtained data, it can be concluded that the Test-Day model allows increasing the accuracy of bull’s evaluation and also more clearly identifying their ranks, as well as slightly reducing the time for obtaining reliable estimates of bulls by offspring for production traits.

An association analysis between PRL genotype and milk production traits in Italian Mediterranean river buffalo

2017 ◽  
Vol 84 (4) ◽  
pp. 430-433 ◽  
Author(s):  
Jun Li ◽  
Aixin Liang ◽  
Zipeng Li ◽  
Chao Du ◽  
Guohua Hua ◽  
...  
Keyword(s):  
Milk Production ◽  
Milk Yield ◽  
Milk Fat ◽  
Fat Content ◽  
Phenotypic Variance ◽  
River Buffalo ◽  
Production Traits ◽  
Milk Production Traits ◽  
Exon 2 ◽  
Mediterranean River

This Research Communication describes the association between genetic variation within the prolactin (PRL) gene and the milk production traits of Italian Mediterranean river buffalo (Bufala mediterranea Italiana). High resolution melting (HRM) techniques were developed for genotyping 465 buffaloes. The association of genetic polymorphism with milk production traits was performed and subsequently the effects of parity and calving season were evaluated. Single nucleotide polymorphisms (SNPs) were identified at exons 2 and 5 and at introns 1 and 2. All the SNPs were in Hardy–Weinberg equilibrium, and statistical analysis showed that the polymorphism of intron1 was significantly (P < 0·05) associated with milk yield, milk protein content and peak milk yield. The average contribution of the intron1 genotype (r2intron1) to total phenotypic variance in milk production traits was 0·09, and the TT genotype showed lower values than CC and CT genotypes. A nonsynonymous SNP was identified in exon 2, which resulted in an amino acid change from arginine to cysteine. Moreover, the polymorphism of exon 2 was associated significantly with milk fat content (P < 0·05), and the buffaloes with TT genotype showed higher total fat content than the buffaloes with CT genotype. These findings provide evidence that polymorphisms of the buffalo PRL gene are associated with milk production traits and PRL can be used as a candidate gene for marker-assisted selection in Italian Mediterranean river buffalo breeding.

scholarly journals Sequence Variations in the Bovine Growth Hormone Gene Characterized by Single-Strand Conformation Polymorphism (SSCP) Analysis and Their Association with Milk Production Traits in Holsteins

Genetics ◽  
1996 ◽  
Vol 144 (4) ◽  
pp. 1809-1816 ◽  
Author(s):  
Jianbo Yao ◽  
Samuel E Aggrey ◽  
David Zadworny ◽  
J Flan Hayes ◽  
Urs Kühnlein
Keyword(s):  
Growth Hormone ◽  
Milk Production ◽  
Milk Yield ◽  
Single Strand Conformation Polymorphism ◽  
Sscp Analysis ◽  
Bovine Growth Hormone ◽  
Production Traits ◽  
Milk Production Traits ◽  
Sequence Variations ◽  
Conformation Polymorphism

Sequence variations in the bovine growth hormone (GH) gene were investigated by single strand conformation polymorphism (SSCP) analysis of seven amplified fragments covering almost the entire gene (2.7 kb). SSCPs were detected in four of these fragments and a total of six polymorphisms were found in a sample of 128 Holstein bulls. Two polymorphisms, a T→C transition in the third intron (designated GH4.1) and an A→C transversion in the fifth exon (designated GH6.2), were shown to be associated with milk production traits. GH4.1c/GH4.1c bulls had higher milk yield than GH4.1c/GH4.1t (P ≤ 0.005) and GH4.1t/GH4.1t (P ≤ 0.0022) bulls. GH4.1c/GH4.1c bulls had higher kg fat (P ≤ 0.0076) and protein (P ≤ 0.0018) than GH4.1c/GH4.1t bulls. Similar effects on milk production traits with the GH6.2 polymorphism were observed with the GH6.2a allele being the favorable allele. The average effects of the gene substitution for GH4.1 and GH6.2 are similar, with ±300 kg for milk yield, ±8 kg for fat content and ±7 kg for protein content per lactation. The positive association of GH4.1c and GH6.2a with milk production traits may be useful for improving milk performance in dairy cattle.

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