Hamed Amirpour Najafabadi

Dr. Hamed Amirpour Najafabadi


Research Focus & Metrics

Academic Career Length

11Years (2016-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
1 January 2019 in Gene
Verified
Journal Article
Closed access
UEUgonna J. Ekegbu
Ugonna J. Ekegbu
LBLucy Burrows
Lucy Burrows
HNHamed Amirpour Najafabadi
Hamed Amirpour Najafabadi
HZHuitong Zhou
Huitong Zhou
Jon Geoffrey Hames HickfordJon Geoffrey Hames Hickford
Jon Geoffrey Hames Hickford

13 September 2016 in Archives Animal Breeding
Verified
Journal Article
Open access
PDF file
HNHamed Amirpour Najafabadi
Hamed Amirpour Najafabadi
SMSaeid Ansari Mahyari
Saeid Ansari Mahyari
MEMohammad Ali Edriss
Mohammad Ali Edriss
ESEva Strapakova
Eva Strapakova
In recent decades, there has been a downward trend in length of productive life (LPL) in Holstein cows across industrial dairy herds. This study examined the factors that might influence LPL and estimated the genetic parameters of LPL in Holstein dairy herds in Isfahan province, Iran. LPL is defined as the number of days between the first calving and the end of recording. Data consisted of 35 137 records of productive life from registered cows that started first calving between 1991 and 2012. Cows that remained alive at the end of the study were considered right-censored. The average lifetime for culled and censored cows was 938 and 1003 days, respectively. A survival analysis was applied using a proportional risk model with a Weibull distribution. Milk production was divided into five groups, where the culling risk of cows with a milk yield of less than 1.5 standard deviations (SD) of the mean was 3.5 times greater than the culling risk of high-producing cows producing more than 1.5 SD above the mean. Results showed that culling risk increased almost linearly beyond the milk production groups. Furthermore, somatic cell count and age at first calving significantly increased the culling risk across the herds. The results for the combined effect of parity × stage of lactation showed a decrease in culling risk during the first calving, and an increase during the further parities. Moreover, a higher age at first calving was observed, reflecting a lower risk of culling. Estimated heritability were 0.074 and 0.18 based on a logarithmic scale and original scale, respectively. According to the results, use of Weibull models showed that the proportional culling risk was higher in low-production cows, but a higher risk ratio was revealed in high-milk-production cows. However, there were some fluctuations in genetic trends, but an overall increase was observed in LPL which will lead to a longer LPL of Holstein cows in Isfahan province.

1 May 2020 in Gene
Verified
Journal Article
Closed access
ISHAKU HARUNAISHAKU HARUNA
ISHAKU HARUNA
UEUgonna J. Ekegbu
Ugonna J. Ekegbu
FUFarman Ullah
Farman Ullah
HNHamed Amirpour Najafabadi
Hamed Amirpour Najafabadi
HZHuitong Zhou
Huitong Zhou
Jon Geoffrey Hames HickfordJon Geoffrey Hames Hickford
Jon Geoffrey Hames Hickford

1 March 2021 in Journal of Equine Veterinary Science
Verified
Journal Article
Closed access
MAMotahareh Ala Amjadi
Motahareh Ala Amjadi
HYHassan Mehrbani Yeganeh
Hassan Mehrbani Yeganeh
MSMostafa Sadeghi
Mostafa Sadeghi
Sayed Haidar Abbas RazaSayed Haidar Abbas Raza
Sayed Haidar Abbas Raza
JYJinmeng Yang
Jinmeng Yang
JAJam Zaheer Ahmed
Jam Zaheer Ahmed

24 January 2020 in Journal of Applied Genetics
Verified
Journal Article
Closed access
PDF file
HDHoushang Dehghanzadeh
Houshang Dehghanzadeh
MGMostafa Ghaderi-Zefrehei
Mostafa Ghaderi-Zefrehei
SMSeyed Ziaeddin Mirhoseini
Seyed Ziaeddin Mirhoseini
SESaeid Esmaeilkhaniyan
Saeid Esmaeilkhaniyan
ISHAKU HARUNAISHAKU HARUNA
ISHAKU HARUNA
HNHamed Amirpour Najafabadi
Hamed Amirpour Najafabadi

31 August 2020 in Reproduction in Domestic Animals
Verified
Journal Article
Closed access
PDF file
HNHamed Amirpour Najafabadi
Hamed Amirpour Najafabadi
MKMajid Khansefid
Majid Khansefid
GMGhassan Ghaith Mahmoud
Ghassan Ghaith Mahmoud
HZHuitong Zhou
Huitong Zhou
Jon Geoffrey Hames HickfordJon Geoffrey Hames Hickford
Jon Geoffrey Hames Hickford