the study was carried out at agarfa atvet college dairy farm to evaluate the reproductive performance of holstein friesian× arsi and holstein friesian ×boran cattle. for the study, records compiled from 1983 to 2012 at the agarfa dairy farm were used as original data. the effects of breed, bloodlines, season and parity on the reproductive traits were evaluated. data were analyzed using the gene...

According to the Cort-Fitness Hypothesis, higher stress levels (glucocorticoids) in vertebrates are correlated to lower fitness. However, recent studies have failed to validate this hypothesis. A proposed wider framework suggests that reproduction can be perceived as an overload adds up to other environmental challenges that individuals must adjust to. In this case, elevated glucocorticoids cou...

this study investigated the effect of dietary supplementation with calcium salts of fatty acids using 48 afshari ewes randomly allocated to four treatments. all groups used in flushing period and only the source of energy were different between rations. the ewes were divided into four groups: a-barely grain; group b-received 5% of csfa with source of flaxseed oil (w3); group c-received 5% of cs...

Received 21 September 2017 Accepted 28 November 2017 In order to identify the effects of nutrients on gene expression and to assess the interactions between genes and nutrition by means of various cutting-edge technologies, the interdisciplinary branch ‘Nutrigenomics’ was created. Therefore, nutrigenomics corresponds to the use of knowledge and techniques of nutrition, genomics, transcriptomics...

The objectives of this study were to evaluate the effects of daily top-dressing (individually feeding on the top of the total mixed ration) with rumen-protected methionine (RPM) from 30 ± 3 until 126 ± 3 Days in milk on productive and reproductive performance in lactating dairy cows. A total of 309 lactating dairy Holstein cows (138 primiparous and 171 multiparous) were randomly assigned to tre...

A scientific substantiation of the main directions program for creating a domestic breed red dairy cattle has been developed, which provides pure breeding and various cross-breeding options to obtain high-producing animals with good reproductive performance productive longevity.

One hundred and sixty adult ewes of the Chios breed were divided randomly into two groups. One group was used for breeding in spring (S) and the other in autumn (A). In both groups oestrous behaviour was detected once a day. Ovulatory activity, 7 d after oestrus, fertility, prolificacy, embryo mortality, birth weight of lambs and milk production were recorded. The percentage of ewes which exhib...

Economic losses caused by enzootic bovine leukosis (EBL) have been of interest since World War II, when the neoplastic form of EBL increased dramatically in Europe. Olson (1974) and House et al. (1975) showed that animals with lymphosarcoma caused by the bovine leukosis virus (BLV) had reduced milk yields, a less efficient reproductive performance and high veterinary costs and mortality rates, ...