phenotypic study of lactation curve in iranian holsteins
نویسندگان
چکیده
a total of 136,250 monthly test day milk records collected from 13,625 iranian holstein heifers (three times a day milking) calved between 1991 and 2001 and distributed over 264 herds were used to study the effects of some environmental factors influencing lacta-tion curve parameters as well as production characteristics. wilmink’s function (yt = w0 + w1t + w2e-0.05t) was fitted to individual lactations. least squares analysis of variance in-dicated that the herd, year and month of calving had a significant effect on all traits under consideration. correlation analysis showed that the parameter w0 had a negative and significant (p
منابع مشابه
The Application of Recursive Mixed Models for Estimating Genetic and Phenotypic Relationships between Calving Difficulty and Lactation Curve Traits in Iranian Holsteins: A Comparison with Standard Mixed Models
In the present study, records on 22872 first-parity Holsteins collected from 131 herds by the Animal Breeding and Improvement Center of Iran from 1995 to 2014 were considered to estimate genetic and phenotypic relationships between calving difficulty (CD) and the lactation curve traits, including initial milk yield (Ap), ascending (Bp) and descending (Cp) slope of the lactation curves, peak mil...
متن کاملComparison of Different Lactation Curve Models to Describe Lactation Curve in Moroccan Holstein-Friesian Dairy Cows
In this study, the incomplete gamma function, an exponential function, a mixed-log function and a polynomial function were evaluated to describe the lactation curve in Moroccan Holstein-Friesian dairy cows. Data from 1990 to 1999, comprising 77130 monthly milk yields of 6029 dairy cows in 280 dairy herds, were used. Edits were carried out by considering the lactation length (5 d and
متن کاملa contrastive study of rhetorical functions of citation in iranian and international elt scopus journals
writing an academic article requires the researchers to provide support for their works by learning how to cite the works of others. various studies regarding the analysis of citation in m.a theses have been done, while little work has been done on comparison of citations among elt scopus journal articles, and so the dearth of research in this area demands for further investigation into citatio...
Effects of twinning on lactation and days open in Holsteins.
Effects of twinning on lactation and days open in Holsteins were studied from calving records compiled by member surveys of Eastern Artificial Insemination Cooperative. Records of cows with 305-day mature-equivalent records from the Northeast Dairy Records Processing Laboratory were grouped according to whether the twin calving was associated with dystocia. Records of each cow that had a twin c...
متن کاملreflections on taught courses of the iranian ma program in english translation: a mixed-methods study
the issue of curriculum and syllabus evaluation and revision has been in center of attention right from when curriculum came into attention of educational institutions. thus everywhere in the world in educational institutions curricula and syllabi are evaluated and revised based on the goals, the needs, existing content, etc.. in iran any curriculum is designed in a committee of specialists and...
focus on communication in iranian high school language classes: a study of the role of teaching materials in changing the focus onto communication in language classes
چکیده ارتباط در کلاس به عوامل زیادی از جمله معلمان، دانش آموزان، برنامه های درسی و از همه مهم تر، مواد آموزشی وابسته است. در تدریس ارتباطی زبان که تاکید زیادی بر توانش ارتباطی دارد، کتاب درسی به عنوان عامل موثر بر پویایی کلاس محسوب میگردد که درس ها را از طریق فراهم آوردن متن ارتباط کلاسی و هم چنین نوع تمرین زبانی که دانش آموزان در طول فعالیت های کلاسی به آن مشغول اند، کنترل می کند. این حقیقت ک...
15 صفحه اولمنابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
journal of agricultural science and technologyناشر: tarbiat modares university
ISSN 1680-7073
دوره 9
شماره Number 4 2010
کلمات کلیدی
میزبانی شده توسط پلتفرم ابری doprax.com
copyright © 2015-2023