EFFECTS OF TOTAL ENVIRONMENTAL CHANGE ON MILK PRODUCTION

1978 ◽  
Vol 58 (4) ◽  
pp. 631-637
Author(s):  
JOHN HODGES ◽  
P. G. HILEY ◽  
J. FROESE
Keyword(s):  
Environmental Change ◽  
Milk Production ◽  
Milk Yield ◽  
Initial Increase ◽  
Fat Percentage ◽  
Gradual Decline ◽  
Protein Percentage ◽  
Coefficients Of Variation ◽  
Change Period ◽  
Percentage Protein

The effects on production of moving a herd of 27 Ayrshire milking cows from one environment to a totally different one, with changed methods of feeding, milking and housing, were studied. Following a pre-change period of 105 days, during which each cow was recorded on alternate days for yield of milk and fat, lactose and protein percentages, the immediate effects of the change, the recovery if any, and permanent changes in production were analyzed over a 19-day period. All traits were affected in mean levels, except protein percentage. Milk yield fell by 2.6 kg (13.0%), fat percentage increased by 0.43 units (10.0%), and lactose percentage fell by 0.23 units (4.8%). Protein percentage was unaltered throughout. Milk yield and lactose percentage did not change after the immediate drop. Fat percentage returned linearly from the initial increase, to expectation at 11 days after the change, and continued to decline for another 8 days. The variances of all the traits were temporarily inflated by factors of 2,5,3 and 3 for milk yield, fat percentage, protein percentage and lactose percentage, respectively. The gradual decline to normal, pre-change variance levels took 7–8 days for compositional traits and 10 days for milk yield. Estimates of these means, variances and coefficients of variation are given.

scholarly journals Associations between polymorphisms of SLC22A7, NGFR, ARNTL and PPP2R2B genes and Milk production traits in Chinese Holstein

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Ruike Jia ◽  
Yihan Fu ◽  
Lingna Xu ◽  
Houcheng Li ◽  
Yanhua Li ◽  
...  
Keyword(s):  
Dairy Cattle ◽  
Milk Production ◽  
Association Analysis ◽  
Milk Yield ◽  
Production Traits ◽  
Milk Production Traits ◽  
Fat Percentage ◽  
Protein Percentage ◽  
Fat Yield ◽  
Percentage Protein

Abstract Background Our preliminary work confirmed that, SLC22A7 (solute carrier family 22 member 7), NGFR (nerve growth factor receptor), ARNTL (aryl hydrocarbon receptor nuclear translocator like) and PPP2R2B (protein phosphatase 2 regulatory subunit Bβ) genes were differentially expressed in dairy cows during different stages of lactation, and involved in the lipid metabolism through insulin, PI3K-Akt, MAPK, AMPK, mTOR, and PPAR signaling pathways, so we considered these four genes as the candidates affecting milk production traits. In this study, we detected polymorphisms of the four genes and verified their genetic effects on milk yield and composition traits in a Chinese Holstein cow population. Results By resequencing the whole coding region and part of the flanking region of SLC22A7, NGFR, ARNTL and PPP2R2B, we totally found 20 SNPs, of which five were located in SLC22A7, eight in NGFR, three in ARNTL, and four in PPP2R2B. Using Haploview4.2, we found three haplotype blocks including five SNPs in SLC22A7, eight in NGFR and three in ARNTL. Single-SNP association analysis showed that 19 out of 20 SNPs were significantly associated with at least one of milk yield, fat yield, fat percentage, protein yield or protein percentage in the first and second lactations (P < 0.05). Haplotype-based association analysis showed that the three haplotypes were significantly associated with at least one of milk yield, fat yield, fat percentage, protein yield or protein percentage (P < 0.05). Further, we used SOPMA software to predict a SNP, 19:g.37095131C > T in NGFR, changed the structure of NGFR protein. In addition, we used Jaspar software to found that four SNPs, 19:g.37113872C > G,19:g.37113157C > T, and 19:g.37112276C > T in NGFR and 15:g.39320936A > G in ARNTL, could change the transcription factor binding sites and might affect the expression of the corresponding genes. These five SNPs might be the potential functional mutations for milk production traits in dairy cattle. Conclusions In summary, we proved that SLC22A7, NGFR, ARNTL and PPP2R2B have significant genetic effects on milk production traits. The valuable SNPs can be used as candidate genetic markers for genomic selection of dairy cattle, and the effects of these SNPs on other traits need to be further verified.

Using quantile regression for fitting lactation curve in dairy cows

2019 ◽  
Vol 86 (1) ◽  
pp. 19-24
Author(s):  
Hossein Naeemipour Younesi ◽  
Mohammad Mahdi Shariati ◽  
Saeed Zerehdaran ◽  
Mehdi Jabbari Nooghabi ◽  
Peter Løvendahl
Keyword(s):  
Quantile Regression ◽  
Dairy Cows ◽  
Milk Production ◽  
Milk Yield ◽  
Information Criterion ◽  
Production Traits ◽  
Milk Production Traits ◽  
Fat Percentage ◽  
Protein Percentage ◽  
Breeding Center

AbstractThe main objective of this study was to compare the performance of different ‘nonlinear quantile regression’ models evaluated at theτth quantile (0·25, 0·50, and 0·75) of milk production traits and somatic cell score (SCS) in Iranian Holstein dairy cows. Data were collected by the Animal Breeding Center of Iran from 1991 to 2011, comprising 101 051 monthly milk production traits and SCS records of 13 977 cows in 183 herds. Incomplete gamma (Wood), exponential (Wilmink), Dijkstra and polynomial (Ali & Schaeffer) functions were implemented in the quantile regression. Residual mean square, Akaike information criterion and log-likelihood from different models and quantiles indicated that in the same quantile, the best models were Wilmink for milk yield, Dijkstra for fat percentage and Ali & Schaeffer for protein percentage. Over all models the best model fit occurred at quantile 0·50 for milk yield, fat and protein percentage, whereas, for SCS the 0·25th quantile was best. The best model to describe SCS was Dijkstra at quantiles 0·25 and 0·50, and Ali & Schaeffer at quantile 0·75. Wood function had the worst performance amongst all traits. Quantile regression is specifically appropriate for SCS which has a mixed multimodal distribution.

DGAT1 polymorphism in Riverine buffalo, Swamp buffalo and crossbred buffalo

2018 ◽  
Vol 85 (4) ◽  
pp. 412-415 ◽  
Author(s):  
Jun Li ◽  
Shenhe Liu ◽  
Zipeng Li ◽  
Shujun Zhang ◽  
Guohua Hua ◽  
...  
Keyword(s):  
Milk Production ◽  
Milk Yield ◽  
Buffalo Milk ◽  
Production Performance ◽  
Production Traits ◽  
Coding Region ◽  
Fat Percentage ◽  
Protein Percentage ◽  
Dgat1 Gene ◽  
Swamp Buffalo

This Research Communication describes the polymorphisms in the coding region of DGAT1 gene in Riverine buffalo, Swamp buffalo and crossbred buffalo, and associations between polymorphisms and milk production performance in Riverine buffalo. Two polymorphisms of DGAT1were identified, located in exon 13 and exon 17, respectively. The distribution of the genotypes of the two SNP loci in different buffalo population varied, especially the polymorphism located in exon 13 which was not found in the Swamp buffalo. Moreover, SNP located in exon 17 was a nonsynonymous switch resulting in the animo acid sequence changed from an arginine (Arg) to a histidine (His) at position 484. Both SNPs were in Hardy–Weinberg equilibrium, and the polymorphism of g.8330T>C in the exon 13 was significantly associated with peak milk yield, total milk yield and protein percentage. The C variant was associated with an increase in milk yield and peak yield but less in protein percentage compared with the T variant. The polymorphisms of g.9046T>C in exon 17 were significantly associated with fat percentage, in that the buffaloes with TT genotype had a significantly higher fat percentage than those with CC genotype. These findings reveal the difference in the genetic evolution of the DGAT1 between Riverine buffalo and Swamp buffalo, and provide evidence that the DGAT1 gene has potential effects for Riverine buffalo milk production traits, which can be used as a candidate gene for marker-assisted selection in buffalo breeding.

AGPAT3 Gene polymorphisms are associated with milk production traits in Chinese Holstein cows

2021 ◽  
pp. 1-6
Author(s):  
Xiaomei Sun ◽  
Yan Liang ◽  
Qisong Gao ◽  
Jiahe Guo ◽  
Cheng Tang ◽  
...  
Keyword(s):  
Milk Production ◽  
Milk Yield ◽  
Nucleotide Polymorphisms ◽  
Production Traits ◽  
Milk Production Traits ◽  
Fat Percentage ◽  
Urea Nitrogen ◽  
Protein Percentage ◽  
Milk Urea ◽  
Milk Urea Nitrogen

Abstract The current study reports the identification of previously undiscovered single-nucleotide polymorphisms (SNPs) in the bovine AGPAT3 gene and further investigates their associations with milk production traits. Our results demonstrate that the major allele C of the SNP g.12264 C > T is positively correlated with test-day milk yield, protein percentage and 305-day milk yield. Importantly, in silico analysis showed that the C/T transition at this locus gives rise to two new transcription factor binding sites (TFBS), E2F1 and Nkx3-2. Polymorphism g.18658 G > A was the only SNP associated with milk urea nitrogen (MUN) with the G allele related to an increase in milk urea nitrogen as well as fat percentage. The GG genotype of SNP g.28731 A > G was associated with the highest fat and protein percentage and lowest 305-day milk yield and somatic cell score (SCS). The association between AGPAT3 locus and milk production traits could be utilized in marker-assisted selection for the genetic improvement of milk production traits and, probably in conjunction with other traits, for selection to improve fitness of dairy cattle.

scholarly journals Can the relation between fat and protein in milk be changed by selective breeding

1947 ◽  
Vol 19 (1) ◽  
pp. 8-21
Author(s):  
T. Lonka
Keyword(s):  
Milk Yield ◽  
Climatic Factors ◽  
Production Capacity ◽  
General Rule ◽  
Regression Equation ◽  
Fat Percentage ◽  
Protein Percentage ◽  
Coefficient Of Correlation ◽  
Rule Set ◽  
The Individual

In Finland the protein content of the feeds is in general so low that it restricts the milk yield particularly in herds of high production capacity. This is especially significant for the reason that owing primarily to climatic factors the quality of the feeds cannot be notably improved in this respect. Therefore an effort should be made to change the composition of milk by means of breeding in such a way that it would correspond to the possibilities of feed cultivation in Finland better than at present. This would mean that it should be endeavoured to breed cows whose milk is very fat-rich but at the same time poor in protein, in which case more of the commercially valuable butterfat could be produced on the feed grown on the estate. Since a correspondingly greater amount of milk of poor protein percentage could be produced than that of protein rich milk, the breeding of such cows would not decrease the yield of protein, which is of such great food value, but as great an amount in kilograms of milk protein would be available as earlier for domestic purposes as well as dairies. We have aimed at this goal in our country in general by endeavouring to raise the fat percentage of the milk by means of breeding. It is known that protein percentage does not increase exactly as markedly as the fat percentage, wherefore the protein yield per kilogram of fat decreases as the percentage rises. The influence of breeding would however be incomparably greater if low protein percentage were selected simultaneously with high fat percentage. In the investigation we have dealt with the possibilities of such selection in Finnish cattle, in connection with which we have striven to make clear how much the protein percentage of the milk varies independently of the fat percentage. The material comprises 54 West-Finnish Native cows; the fat and protein percentages of their milk yield has been determined once a month during one lactation. The relation of fat and protein is not the same throughout the whole lactation, but it changes so that at the end of the lactation the protein percentage as compared with the fat percentage is relatively greater than at the beginning of the period (Table and Figure 1). The averages of the fat and protein percentages and likewise the correlation between them depend consequently upon the length of the calving interval. Therefore the said averages have been estimated only on the basis of 2—7 production months. Fy means of these averages r = +0.60 ± 0.09 was derived as the coefficient of correlation between the fat and protein percentages y = 1.53 + 0.39 x as the regression equation, x = fat percentage and y = protein percentage. The individual cows diverge very much from the general rule set by the regression equation, which can be concluded already from the comparatively low value of the coefficient of correlation. The protein percentage of the milk yield of the West- Finnish Native cows diverges at least about one per cent independently of the fat percentage when judging on the basis of the extreme divergencies in the material. Although a part of the divergency evidently is caused by external factors, the role of the genetic factors is nevertheless so great that there appear to be great possibilities for breeding cows producing fat-rich milk by means of breeding but having a protein which would be considerably lower than the present average.

scholarly journals To the question of evaluating the efficiency of linear breeding in Simmental cattle breed different origin

2020 ◽  
Vol 197 (6) ◽  
pp. 49-57
Author(s):  
L. Ignat'eva ◽  
A. Konte ◽  
A. Sermyagin
Keyword(s):  
Milk Production ◽  
Milk Yield ◽  
Russian Federation ◽  
Mixed Model ◽  
Breeding Value ◽  
Production Traits ◽  
Fat Percentage ◽  
Foreign Origin ◽  
Simmental Cattle ◽  
The Impact

Abstract. The purpose of the research – to study the impact of related foreign pedigree resources on the Russian population of Simmental cattle. Research Methods. Studies carried out on cows of Simmental breed of different linear origin and genotypes in five regions of Russian Federation: Voronezh, Oryol, Kursk, Belgorod regions and Altayskiy krai, the total number was 35147 cows. EBV estimates were calculated through RENUMF 90, REMLF 90 and BLUPF 90 programs. Evaluation of the components of the variants of genetic and paratypical nature was carried out using the method restricted maximum likelihood – REML. Results. It is established that the largest share for animals foreign origin are 60.7 %, including German-Austrian bloodlines 46.6 % and Holsteins – 14.1 %. 39.3 % of animals are the Russian origin, which 13.5 % representatives of German-Austrian bloodlines, 17.8 % are Holsteins and 8.0 % are from domestic (Russian) bloodlines. In the general population of Simmental breed, the best productivity was shown by cows of German-Austrian bloodlines at the level of 5351 kg of milk with fat percentage 4.00 % and protein percentage 3.19 %. Representatives of German-Austrian bloodlines origin for milk yield showed the estimated breeding value (EBV) for Simmental bulls in the common population by +9.2 kg and fat percentage by +0.012 %. The negative EBV values were obtained for Russian bloodlines by –22.8 kg, and Holstein bloodlines took an intermediate position among all lines (+2.3 kg). The first calving cows, which were in the herd at the time of research, the best milk production traits were found in individuals of foreign origin, both for Holstein (6096 kg of milk with a fat content of 3.96 % and protein 3.23 %), and German-Austrian bloodlines (milk yield 5763 kg, fat 4.04 % and protein 3.19 %), with high estimates of breeding value for milk yield +33.3 kg and +15.2 kg, respectively. Low values of milk productivity among all evaluated animals were observed for animals of Russian bloodlines by 4469 kg milk 3.87 % fat and 3.20 % protein in milk. The first calving cows of Russian origin in foreign bloodlines origin exceeded their peers in Russian Simmental bloodlines in milk production by +608 kg of milk and +0.15 % fat (signed to German-Austrian bloodlines) and +924 kg and +0.06 % fat (signed to Holstein bloodlines). The average values of EBV in these lines, although had low values by –5.6 kg milk for Holstein and by +2.7 kg milk for German-Austrian bloodlines, but was significantly higher than for Russian lines by –12.7 kg milk. Scientific novelty. For the first time, scientific research aimed at improving the system of prediction to breeding abilities of bulls on dairy productivity of daughters based on optimization structure of equations of the mixed model (BLUP, the best linear unbiased prediction) has been carried out for the population Simmental cattle of Russian Federation.

scholarly journals Genetic Effects of LPIN1 Polymorphisms on Milk Production Traits in Dairy Cattle

Genes ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 265 ◽  
Author(s):  
Bo Han ◽  
Yuwei Yuan ◽  
Ruobing Liang ◽  
Yanhua Li ◽  
Lin Liu ◽  
...  
Keyword(s):  
Milk Production ◽  
Milk Yield ◽  
Genetic Effects ◽  
Production Traits ◽  
Milk Production Traits ◽  
Association Analyses ◽  
Protein Percentage ◽  
Haplotype Blocks ◽  
Flanking Region ◽  
Fat Yield

Our initial RNA sequencing work identified that lipin 1 (LPIN1) was differentially expressed during dry period, early lactation, and peak of lactation in dairy cows, and it was enriched into the fat metabolic Gene Ontology (GO) terms and pathways, thus we considered LPIN1 as the candidate gene for milk production traits. In this study, we detected the polymorphisms of LPIN1 and verified their genetic effects on milk yield and composition in a Chinese Holstein cow population. We found seven SNPs by re-sequencing the entire coding region and partial flanking region of LPIN1, including one in 5′ flanking region, four in exons, and two in 3′ flanking region. Of these, four SNPs, c.637T > C, c.708A > G, c.1521C > T, and c.1555A > C, in the exons were predicted to result in the amino acid replacements. With the Haploview 4.2, we found that seven SNPs in LPIN1 formed two haplotype blocks (D′ = 0.98–1.00). Single-SNP association analyses showed that SNPs were significantly associated with milk yield, fat yield, fat percentage, or protein yield in the first or second lactation (p = < 0.0001–0.0457), and only g.86049389C > T was strongly associated with protein percentage in both lactations (p = 0.0144 and 0.0237). The haplotype-based association analyses showed that the two haplotype blocks were significantly associated with milk yield, fat yield, protein yield, or protein percentage (p = < 0.0001–0.0383). By quantitative real-time PCR (qRT-PCR), we found that LPIN1 had relatively high expression in mammary gland and liver tissues. Furthermore, we predicted three SNPs, c.637T > C, c.708A > G, and c.1521C > T, using SOPMA software, changing the LPIN1 protein structure that might be potential functional mutations. In summary, we demonstrated the significant genetic effects of LPIN1 on milk production traits, and the identified SNPs could serve as genetic markers for dairy breeding.

Milk production, milk composition, and reproductive function of dairy cows fed different fats

2001 ◽  
Vol 81 (2) ◽  
pp. 263-271 ◽  
Author(s):  
H. V. Petit ◽  
R. J. Dewhurst ◽  
J. G. Proulx ◽  
M. Khalid ◽  
W. Haresign ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Milk Production ◽  
Milk Yield ◽  
Milk Fat ◽  
Plasma Concentrations ◽  
Reproductive Function ◽  
Fat Percentage ◽  
Blood Concentrations ◽  
Flaxseed Meal ◽  
Fat Supplements

Thirty-five non-gestating multiparous Holstein cows averaging 571 kg of BW (SE = 8) were allotted at 9 wk postpartum to one of two dietary fat supplements based on either Megalac® (Volac Ltd., Roston, Hertfordshire, UK) and solvent extracted flaxseed meal (MEGA) or whole flaxseed treated with formaldehyde (FLAX) to determine the effects on milk production and composition, follicular development, gestation rate, and fatty acid (FA) composition of blood. Cows were fed a total mixed diet based on ryegrass silage and fat supplements for ad libitum intake. The experiment was carried out between weeks 9 and 19 of lactation. Dry matter (DM) intake and change in body weight were similar for cows fed MEGA and FLAX. Milk production was higher for cows fed MEGA than for those fed FLAX (19.8 vs. 18.6 kg d–1) as was 4% fat-corrected milk yield (22.9 vs. 20.2 kg d–1). Increased fat mobilization could have contributed to increased milk yield when cows were fed MEGA compared with when they were fed FLAX as plasma concentrations of non-esterified FA and cholesterol increased more from weeks 9 to 19 of lactation for cows fed MEGA. Milk fat percentage tended (P = 0.06) to be greater for cows fed MEGA (4.62%) compared with those fed FLAX (4.37%). Milk protein percentage was higher for cows fed FLAX (3.09%) than for those fed MEGA (2.95%), indicating that formaldehyde protection of flaxseed was adequate to partly prevent ruminal degradability of protein in the seed. Milk fatty acid concentrations of C8:0, C10:0, C12:0, C14:0, C14:1, C18:0, C18:3, and C20:5 were higher for cows fed FLAX than for those fed MEGA while the inverse was observed for C16:0, C16:1, C18:1, and C18:2. Cows fed FLAX had lower blood concentrations of C16:0 than those fed MEGA. There was a significant interaction (P < 0.05) between week and diet for C18:0 and C18:2 with a decrease in C18:0 blood concentration for cows fed MEGA and an increase for those fed FLAX between weeks 9 and 19, while the inverse was observed for C18:2. Blood concentrations of C18:1 were similar for both treatments. Conception rate was significantly lower for cows fed MEGA (50.0%) compared to those fed FLAX (87.5%). Diet had no effect on the size of the largest and second largest follicles, or on the difference between the diameter of the largest and second largest follicles. The number of class 1 (1.09 vs. 0.86), 2 (1.33 vs. 0.86), and 3 (1.28 vs. 0.98) follicles was similar for MEGA and FLAX although the total number (3.70 vs. 2.70) of follicles tended (P = 0.09) to be greater for cows fed MEGA than for those fed FLAX. These data suggest that dietary FA have an effect on gestation rate, but this could not be explained by differences in follicle dynamics or number. However, additional trials with greater numbers of animals are needed to confirm the reproductive results. Key words: Dairy, flaxseed, milk production, reproduction, fatty acids

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 Determination of a possible relationship between a single nucleotide polymorphism (SNP) in the promoter region of the <i>SIRT1</i> gene and production and reproduction traits in the Agerolese cattle breed

2019 ◽  
Vol 62 (1) ◽  
pp. 107-112 ◽  
Author(s):  
Maria Selvaggi ◽  
Claudia Carbonara ◽  
Francesca Ciotola ◽  
Sara Albarella ◽  
Giulio Aiudi ◽  
...  
Keyword(s):  
Milk Production ◽  
Milk Yield ◽  
Promoter Region ◽  
Class Iii ◽  
Fat Percentage ◽  
Single Nucleotide ◽  
Genotype Frequencies ◽  
Reproduction Traits ◽  
Daily Milk Yield ◽  
Daily Milk

Abstract. Sirtuins (sir2-like proteins) belong to the family of class III NAD+-dependent histone deacetylases. Among them, SIRT1 is the most studied sirtuin. It plays a key role in many biological processes in the liver, adipose tissue, muscle, pancreas, testis, ovary and mammary gland. It has an important function in endocrine signaling, with a specific role in glucose and fat metabolism. To date, in bovine species, only few SIRT1 single nucleotide polymorphisms (SNPs) have been reported in the literature. Thus, the aims of the present study were to estimate the allele and genotype frequencies at the g.-274C > G locus in the promoter region of the SIRT1 gene and to investigate, for the first time, the relationship among different genotypes and milk production and some reproduction traits in a sample of cows belonging to the Agerolese breed. All the animals were genotyped at the abovementioned locus using the PCR-RFLP technique. The investigated population was found to be polymorphic at the investigated locus. Concerning milk production performances, significant differences between genotypes were found in daily milk yield (DMY), fat percentage (FC), lactation length (LL), peak daily milk yield (PY) and 305-day milk yield (305MY). Moreover, the effect of the g.-274C > G genotype on age at first calving and calving period was significant. In conclusion, our findings are promising and should encourage scientists to further investigate the effect of genetic polymorphism of sirtuins on milk performance and reproductive traits.

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