The insulin-like growth factor 1 (IGF-1) is considered to be a factor that mainly regulates growth, differentiation, and the maintenance of various function in numerous tissues through binding to a family of transmembrane tyrosine kinase receptors, signaling primarily through the insulin-like growth factor 1 receptor (IGF-1R) encoded by the IGF1R gene. The objectives of the present study were to estimate the allele and genotype frequencies of the IGF1R/MspI (silent mutation within exon 12) and the IGF1R/TaqI (within the 3′ untranslated region, 3′UTR) gene polymorphisms in beef cattle and to determine associations between these polymorphisms and growth traits. In a preliminary study on 310 Angus calves, association analyses with three production traits (birth weight, BWT; weaning weight adjusted to 210 days, WWT210; and average daily gain, ADG) were conducted. The GG genotype of the IGF1R/e12/MspI polymorphism was significantly associated (P ≤ 0.05) with a higher WWT210 (+5.06 kg) compared to the AG genotype. Polymorphism within the 3′UTR had no significant effect on growth traits. The effect of combined genotypes was also examined. At WWT210, calves with the GG/AA and GG/AG combinations were heavier than calves with the AG/AA and AG/AG combined genotypes (P ≤ 0.05). To our knowledge, this is the first report of a polymorphism within the coding region of the Bos taurus IGF1R gene.

The study was carried out on 658 Polish Holstein Friesian cows. A transversion of A→C in the P1 promoter region of bovine IGF1 gene at position 977 bp upstream from the start codon in exon 1 was identified using ACRS-PCR method. Reverse primer introduced an artificial TasI restriction site. Three genotypes (AA, AC, CC) were found in the analysed herd of dairy cows occurred with a frequency of 0.766, 0.213 and 0.021, respectively. In the presented study, the statistically significant differences between individuals of different IGF1/TasI genotypes were found in milk, fat and protein yield. In the 2nd and 3rd lactations, the cows carrying the CC genotype produced more milk than the AA individuals (P≤0.05). In the case of protein and fat yield, similar tendencies were observed.

ABSTRACT:The aim of this study was to estimate potential relationships between insulin-like growth factor I gene polymorphisms (IGF1/TasI and IGF1/SnaBI) and the growth parameters of calves as well as their subsequent milk performance. The study involved a total of 191 Polish Holstein-Friesian var. Black-and-White calves. Both polymorphic sites were determined with Amplification Created Restriction Sites-Polymerase Chain Reaction (ACRS-PCR). In the case of the IGF1/SnaBI polymorphism, the genotype and allele frequencies were as follows: TT -0.27, CT -0.55, CC -0.18, T -0.54, and C -0.46. The CC genotype was favourable and associated with higher body weight at the 2 nd month of age of calves (WT60) and their daily body weight gains from the 1 st to the 2 nd month (P ≤ 0.05) as well as subsequent milk, fat, and protein yield (P ≤ 0.01). For the IGF1/TasI polymorphism, the highest frequency of the AA genotype (0.69) was found. Allele frequencies were 0.75 and 0.25 for the A and C alleles, respectively. In the association study, the AC genotype was significantly associated with higher WT60 and average daily gains in the periods from the 2 nd to the 3 rd month of age and for the whole rearing period (P ≤ 0.05) as well as subsequent milk, fat, and protein yield (P ≤ 0.01). Combined genotypes were also included into the analysis. The highest yields of milk as well as fat and protein were found in cows with the CC/AA combination. No clear relationships between body weight and genotype combination were found.

Abstract. The study aimed at evaluation of the effect of colostral supplement on humoral immunity, growth and health state of calves until the 3rd month of life. Examinations were carried out on 40 Polish Black-and-White Holstein-Friesian calves. After birth, the calves were separated into two groups (20 calves each): control group – without addition of colostral supplement, and experimental one – with colostral supplement in diet. Blood was sampled from each calf on day 5 and 30 of life, and total protein, albumin, and alpha, beta and gamma globulin levels were determined in it. Evaluation of calves’ growth and development course was carried out basing on weighing and daily gain results. The favourable effect of colostral supplement on calves’ health state and body weight gains was found. No significant effect of colostral supplement on total protein level or gamma-globulin fraction level was found. The effect of colostral supplement on reduction of alpha-globulin fraction decrease was found in a time period until the 30th day of calves’ life (P≤0.01). The study so far point to the purposefulness of using this supplement, in particular in the case of colostrum deficiency or its poor quality.

In the work presented, an analysis of the genetic values of conformation traits and their relations with the genetic value of dairy traits based on dairy performance (milk, fat and protein yield) and conformation data, was performed. Data were obtained for Polish Holstein-Friesian cows of the Black-and-White variety, maintained in 21 herds in the region of Wielkopolska (central Poland) and born between 2001 and 2004. The genetic values for the data analysed were estimated using the BLUP (best linear unbiased prediction) method and a mixed model. For the traits analysed, a genetic trend as well as genetic correlations between the dairy and conformation traits were estimated. The population analysed was divided depending on the year of birth and production level. The results obtained show a systematic increase in the traits analysed (positive genetic trends) both for dairy and conformation traits (with the exception of temperament). The highest genetic correlations between dairy and conformation traits were obtained for the udder, temperament and dairy type, while the lowest were obtained for height at sacrum and calibre. The analysis of the genetic value of conformation traits in cows of different dairy production genetic values indicated that the highest results were obtained for the group of animals with the highest genetic dairy production value. In turn, the analysis of the genetic value of traits of cows born in different years did not show statistically significant differences, with the exception of height in the youngest group.