نتایج جستجو برای: interval between calving to first insemination
تعداد نتایج: 11258826 فیلتر نتایج به سال:
The successful genetic selection for higher milk production caused a dramatic decline in the reproductive performance of dairy cows all over the world during the last decades. Achievement of optimum herd reproductive performance (calving interval of 12 or 13 months with the first calf born at 24 months of age) requires concentrated management activities especially during the first 100 days foll...
chapter one is devoted to a moderate discussion on preliminaries, according to our requirements. chapter two which is based on our work in (24) is devoted introducting weighted semigroups (s, w), and studying some famous function spaces on them, especially the relations between go (s, w) and other function speces are invesigated. in fact this chapter is a complement to (32). one of the main fea...
in this thesis our aim is to construct vector field in r3 for which the corresponding one-dimensional maps have certain discontinuities. two kinds of vector fields are considered, the first the lorenz vector field, and the second originally introced here. the latter have chaotic behavior and motivate a class of one-parameter families of maps which have positive lyapunov exponents for an open in...
A total of 245187 records of the first three lactations of 131126 Holstein cows in tropical conditions were used to estimate the genetic (co)variance components between age at calving and its respective milk productions. A multivariate analysis of six traits was performed. Heritability for age at calving (h2AC) and milk yield (h2MY) decrease from the ...
CONSTRAINTS LIMITING THE EFFICIENCY OF ARTIFICIAL INSEMINATION OF CATTLE IN BANGLADESH. The aim of the present study was to identify the factors that influence postpartum intervals to first detected luteal activity, first service and to conception, and the conception rates of cows in the artificial insemination (AI) programme in Bangladesh. A baseline survey (investigations 1, 2 and 3) was made...
Declining reproductive performance is a serious breeding concern in many countries. To reveal the situation in Norwegian cattle, trends in reproductive performance were studied using insemination reports from 1985 to 2005 and data based on herd recording files from 1989 to 2005. The total number of first services was 469.765 in 1985 declining to 335.712 in 2005. The number of recorded herds and...
Gunay A., U. Gunay: Effects of Clinical Mastitis on Reproductive Performance in Holstein Cows. Acta Vet. Brno 2008, 77: 555-560. The objective of this study was to determine the effects of clinical mastitis on reproductive performance in 135 early lactation cows. The animals were divided into two groups according to the occurrence of mastitis as follows: group I (n = 45), clinical mastitis prio...
The objective of this study was to evaluate effects of a daily oral drench of Propylene Glycol (PG) on fertility in dairy cows experiencing seasonal heat stress. In treatment group, cows (n=9) were treated with drenching 250 ml propylene glycol once daily from 3 to 15 days post-partum following the morning milking. Another group of cows (n=9) was selected as untreated control. The serum beta-hy...
Fertility, represented by calving interval, has been included in the genetic evaluation of Icelandic cattle since 1993. In spite this an unfavourable trend is seen and, recent implementation test-day models for milk production changed premise using interval to represent fertility. The aim study was estimate parameters and trends different female fertility traits dairy suggest new evaluation. In...
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