________________________________________________________________________________________ KUl, E., A. ŞAHİn, S. ATASEvEr, E. UğUrlUTEpE, M. SoydAnEr: The effects of somatic cell count on milk yield and milk composition in Holstein cows. vet. arhiv 89, 143-154, 2019. ABSTrACTThis study was conducted to assess the impact of somatic cell count (SCC) on the test day milk yield (TDMY) and milk composition parameters (fat, solids-not-fat, protein and lactose) of Holstein cows raised in the Kırşehir province of Turkey. A total of 1194 raw milk samples were collected from 195 Holstein cows at different stages of lactation (from 1 to 7), parities (from 1 to 3) and calving seasons (autumn, winter, spring and summer). Also, TDMY and milk composition traits were tested by SCC in four groups (<100×10 3 , 100-200×10 3 , 201-500×10 3 and >500×10 3 cells/mL). For statistical evaluation, SCC data were converted to log 10 base. The overall means of log 10 SCC, TDMY, fat, solids-not-fat (SNF), protein and lactose were determined as 4.95 ± 0.016, 33.36 ± 0.232 kg/day, 3.39 ± 0.021%, 9.04 ± 0.013%, 3.32 ± 0.005% and 4.92 ± 0.007%, respectively. Log 10 SCC, TDMY, fat, SNF, protein and lactose were significantly affected by the stage of lactation, parity and calving seasons (P<0.05). An increase in the SCC was accompanied by a decrease in the milk yield as well as its content (P<0.05). Cows' milk with high SCC (>201×10 3 cells/mL) had a lower TDMY than milk with lower SCC (<100×10 3 and 100-200 cells/mL). However, the lowest fat, SNF, protein and lactose were determined in milk with SCC >500×10 3 cells/mL. It was concluded that SCC in milk should not exceed 500×10 3 cells/mL for Holstein cows, suggesting that monthly control of SCC may be effective for improving milk production and milk quality in Holstein cows.

Erdem, H., Atasever, S. and Kul, E. 2010. Relationships of inillrability traits to udder characteristics. milk yield and somatic cell count in Jersey cows. J. Appl. Anim. Res., 37: 43-47. To determine th.e rehtionships between nzilhbility traits (MT) and some chamcteristics obtained frorrt u d d w riiea,szLi*ements, udder scores, ntillz yield tra.its nnd soniatic cell count (SCC) of ntilk a total of 195 Jersey cows reared at Kcl.rahoy State Farm, Turkey were used. Effects of parity (P), stage of 1acta.tion (SL) arid ntilk yield level (MY) were significant on test day ntillt yield (TDMY). Negative or positive correlations were observed between udder traits a.nd TDMY, ntillting speed (MS) or milking duration (MD

No abstract

Abstract:The main purpose of this study was to detect an association of cytoplasmic signal transducers and activators of transcription-1 (STAT1) with milk production traits in 472 Holstein and 283 Jersey cattle breeds of Turkey. This gene, located on chromosome 2, was chosen due to its role on development of mammary gland. A polymorphism of selected 314 bp allele fragment was detected by the restriction fragment length polymorphism analysis of polymerase chain reaction-amplified fragments (PCR-RFLP) method and also confirmed by DNA sequencing. The association tests were conducted between STAT1 genotypes and some economically important dairy traits. The genotypes for C/T as a single nucleotide polymorphism (SNP) were identified at interval 60 cM to 63 cM. The effects of STAT1 gene on milk production traits were not significant in Holstein cows, although animals with CT genotypes showed fairly close to significant value for the corrected 305 d milk yield. However, Jersey cows with TT genotype were 2.07 kg higher for test-day milk yield (P < 0.05), 0.13 kg for fat yield (P < 0.01) and 0.07 kg for protein yield (P < 0.05) compared with animals having CC and CT genotypes. Definitely, the further research should be conducted to search this gene intensively with larger samples to identify polymorphism and any association between the economically important traits and genotypic class in Holstein cows. Finally, based on the findings, it was concluded that STAT1 gene might be used as a potential candidate gene to improve milk yield and milk fat and protein contents in dairy cows breeding programs.

No abstract