this experiment was carried out in experimental farm of agricultural faculty of ferdowsi university of mashhad, iran during 2010. the design was split plot with three replications. main plots were the medicinal plant species consist of: blond psyllium (plantago ovate forssk.), clasping peperweed (lepidium perfoilatum l.), qodumeh shirazi (alyssum homolocarpum l.) dragon's head (lalementia iberi...

this study was conducted to evaluate the effect of fertilizers on the yield and essential oils of basil. this experiment was carried out in completely randomized block design with three replications in jiroft area. the treatments included three levels of barvar 2 (10, 20 and 25 g/ha), cow manure at three levels (5, 10 and 15 ton/ha), ammonium phosphate and superphosphate triple each at three le...

Involuntary culling (IC) is where a cow is disposed of due to injury, poor health or infertility. The main reasons for IC are infertility, mastitis and lameness. These reasons have differing age profiles in when they affect cows, cost variable amounts to treat and have an effect on the value of the cow at market. They also reduce cow welfare in different ways. These factors influence the econom...

A cross-sectional study was carried out in spring 2007, at the end of the first bluetongue outbreak season, to determine the geographical spread of bluetongue virus serotype 8 (btv-8) infection in cattle in the Netherlands and the consequences for some production parameters. Blood samples from cattle submitted to the laboratory of the Dutch Animal Health Service for other voluntary and obligato...

Data from Hereford, 25% Simmental-75% Hereford, 50% Simmental-50% Hereford, and 75% Simmental-25% Hereford dams were used to estimate maternal heterosis and level of agreement with the dominance model. Cows were located at the Northern Agricultural Research Center near Havre, MT and were managed consistent with practices for western range environments. Sample halves of dam breed groups were bre...

The objective of this thesis was to evaluate genetic aspects of longevity (LPL) in the Chianina beef cattle population in order to define how to include this trait in selection criteria. The Chianina breed has been raised for over twenty-two centuries in Italy and today this breed is present in different countries across Europe, South and Central America, Australia, Canada and the USA. Its char...

Inbreeding results from the mating of related individuals and is becoming increasingly important in domestic livestock populations. Inbreeding depression is the reduction of the mean phenotypic value, particularly for traits connected with reproduction or fitness (Miglior et al., 1992). Inbreeding depression has been shown to decrease milk production by approximately 9-26 kg of milk per lactati...

The objective this research was to determine the effect of application of multiple grazing management practices at 2 stocking rates (SR) on the productivity and economics of the cow-calf enterprise in the Southeastern United States over a 4-yr period. Pasture management systems included: continuous grazing management at a moderate SR (0.8 ha/cow; CG) without additional forage management, rotati...

Bovine-leukosis virus (BLV; also termed 'bovine-leukemia virus') is a retrovirus that primarily affects lymphoid tissue of dairy and beef cattle. Our objective was to investigate the association between BLV infection and annual value of production (AVP) on dairy herds within the United States, as part of the USDA National Animal Health Monitoring System's 1996 dairy study. 1006 herds (in 20 sta...

successful pasture-based milk production systems pivot on balancing dairy cows’ feed requirements with seasonal and annual fluctuations in pasture production. in order to maximise cow production from grazing dairy systems, it is necessary to reach an efficient utilization of grazed grass for feeding cows and the development of appropriate grazing management systems designed to maximize daily pa...