Interrelationship of growth hormone AluI polymorphism and hyperketonemia with plasma hormones and metabolites in the beginning of lactation in dairy cows

IGF-I and GH Genes polymorphism and their association with milk yields, composition and reproductive performance in Holstein-Friesian dairy cattle

BACKGROUND

The insulin-like growth factor (IGF-I) and growth hormone (GH) genes have been identified as major regulators of milk yield and composition, and reproductive performance in cattle. Genetic variations/polymorphism in these genes have been found to influence milk production, yield and quality. This investigation aimed to explore the association between IGF-I and GH polymorphisms and milk yield and composition, and reproductive performance in a herd consisting of 1000 Holstein-Friesian (HF) dairy cattle from El-Alamia farm. The experimental animals were 76 ± 7.25 months in age, with an average live weight of 750 ± 50.49 kg, and raised under the same conditions of feeding and weather. The studied animals were divided into three categories; high producers (n = 280), medium producers (n = 318) and low producers (n = 402).

RESULTS

The digestion of 249 bp for IGF-I-SnaBI using the Restriction-fragment-length-polymorphism (RFLP) technique yielded two alleles; T (0.59) and C (0.41) and three genotypes; TT (0.52), TC (0.39) and CC (0.09) and this agrees with the results of DNA/gene sequencing technique. The sequencing analysis of the IGF-I gene revealed polymorphism in position 472 (C > T). Nucleotide sequencing of the amplified fragment of the IGF-I gene of different genotypes was done and submitted to the NCBI GenBank with Accession no. MH156812.1 and MH156811.1. While the digestion of 432 bp for GH-AluI using the RFLP technique yielded two alleles; A (0.81) and G (0.19) and two genotypes; AA (0.77) and AG (0.23) and this agrees with the results of DNA/gene sequencing technique. The sequencing analysis of the GH gene revealed polymorphism in the position 1758 C > G and in turn led to changes in amino acid sequence as Alanine for (A) compared to Glycine for (G). Nucleotide sequencing of the amplified fragment of the GH gene was done and submitted to the NCBI GenBank with Accession no. MH156810.1. The results of this study demonstrate the effects of variants of the GH-IGF-I somatotrophic axis on milk production and composition traits in commercial HF cattle. The greatest values of milk yield and reproductive performance were observed on IGF-I-SnaBI-TC and GH-AluI-AG genotypes. While the greatest % fat and % protein values were observed on IGF-I-SnaBI-CC and GH-AluI-AA genotyped individuals.

CONCLUSION

The genetic variation of the studied genes can be utilized in selecting animals with superior milk yield, composition and reproductive performance in Holstein-Friesian Dairy Cattle under subtropical conditions.

Association of milk production traits with genetic variants in exon 5 and intron 3 of bovine growth hormone (bGH) gene in Sahiwal cattle

The main objective of this study was to determine the association of production traits with genetic variants in exon 5 and intron 3 of bovine growth hormone (bGH) gene in Sahiwal cattle. The analyses were based on the detection of single nucleotide polymorphisms (SNPs) in GH-AluI (exon 5) and GH-MspI (intron 3) using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. The frequency of AluI (L/V) and MspI (T/C) alleles were 86.20/13.70 and 89.80/9.50, respectively. The distribution of the frequency of GH genotypes for LL, LV, and VV were 73.4, 25.5, and 1.0 and for TT, TC, and CC genotypes were 80.9, 17.7, and 13.0, respectively. Season of calving had none but period of calving had significant effect on the studied production traits. The phenotypic data was adjusted for non-genetic factors and regression analysis was done. There was detectable significant effect of the GH-AluI and GH-MspI on the analyzed production traits. The cows with LL genotype had significantly higher milk yield traits than the LV genotype. Similarly, the productive performance of the studied cows with TT genotype was also significantly higher than TC and CC genotypes. Results revealed that the Sahiwal cows with LL and TT genotypes of the bGH locus can be considered to be a favourable genotype for production traits, although these findings need to be confirmed by further research before SNPs can be used in a marker assisted selection program by the animal breeder.

Assessment of growth hormone gene polymorphism effects on reproductive traits in Holstein dairy cattle in Tunisia

Research to assess the effect of single genes on reproductive traits in bovine species is imperative to elucidate genes' functions and acquire a better perspective of quantitative traits. The present study was undertaken to characterize genetic diversity in the bovine growth hormone (GH) gene in a population of 410 Holstein dairy cows in Tunisia. The analyses were based on single nucleotide polymorphisms, and GH-AluI and GH-MspI detections and genotyping were carried out using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Data were analyzed using a mixed linear model with the MIXED procedure to reveal the possible effect of GH genotypes on reproductive traits. The frequency data of AluI(L//V) and MspI( + // - ) alleles were 87.04//12.96 and 70.06//29.94, respectively. The distribution of the frequency of GH genotypes for LL/LV/VV and ( - / - )//( + / - )//( + / + ) were 77.75//18.59//3.66 and 15.37//29.13//55.50, respectively. The results of the statistical analyses proved that GH-AluI showed a substantial favorable effect on exanimate traits except for the age at first calving; however, only a suggestive effect of GH-MspI on the calving interval (CI) and the days open (DI) was found. The homozygous LL genotype seemed to be advantageous with respect to the CI and the DI compared with LV and VV genotypes. Heterozygous MspI( + / - ) cows tended to have a longer CI and DI than MspI( + / + ) and MspI( - / - ) cows, but the difference was not statistically significant. A significant effect of different GH-AluI-MspI combined genotypes was found on the number of inseminations per conception, the CI and the DI, and the LL/- combined genotype seemed to be associated with better reproductive performance. Based on these results, the LL genotype of the GH locus can be considered to be a favorable genotype for reproductive traits in Holstein dairy cattle, although these findings need to be confirmed by further research before polymorphisms can be used in a marker-assisted selection program.

Metabolic and endocrine profiles and reproductive parameters in dairy cows under grazing conditions: effect of polymorphisms in somatotropic axis genes

Background

The present study hypothesized that GH-AluI and IGF-I-SnabI polymorphisms do change the metabolic/endocrine profiles in Holstein cows during the transition period, which in turn are associated with productive and reproductive parameters.

Methods

Holstein cows (Farm 1, primiparous cows, n = 110, and Farm 2, multiparous cows, n = 76) under grazing conditions were selected and GH and IGF-I genotypes were determined. Blood samples for metabolic/endocrine determinations were taken during the transition period and early lactation in both farms. Data was analyzed by farm using a repeated measures analyses including GH and IGF-I genotypes, days and interactions as fixed effects, sire and cow as random effects and calving date as covariate.

Results and Discussion

Frequencies of GH and IGF-I alleles were L:0.84, V:0.16 and A:0.60, B:0.40, respectively. The GH genotype was not associated with productive or reproductive variables, but interaction with days affected FCM yield in multiparous (farm 2) cows (LL yielded more than LV cows) in early lactation. The GH genotype affected NEFA and IGF-I concentrations in farm 1 (LV had higher NEFA and lower IGF-I than LL cows) suggesting a better energy status of LL cows.

There was no effect of IGF-I genotype on productive variables, but a trend was found for FCM in farm 2 (AB cows yielded more than AA cows). IGF-I genotype affected calving first service interval in farm 1, and the interaction with days tended to affect FCM yield (AB cows had a shorter interval and yielded more FCM than BB cows). IGF-I genotype affected BHB, NEFA, and insulin concentrations in farm 1: primiparous BB cows had lower NEFA and BHB and higher insulin concentrations. In farm 2, there was no effect of IGF-I genotype, but there was an interaction with days on IGF-I concentration, suggesting a greater uncoupling somatropic axis in AB and BB than AA cows, being in accordance with greater FCM yield in AB cows.

Conclusion

The GH and IGF-I genotypes had no substantial effect on productive parameters, although IGF-I genotype affected calving-first service interval in primiparous cows. Besides, these genotypes may modify the endocrine/metabolic profiles of the transition dairy cow under grazing conditions.