The importance of individuals to the dynamics of populations may depend on reproductive status, especially for species with complex social structure. Loss of reproductive individuals in socially complex species could disproportionately affect population dynamics by destabilizing social structure and reducing population growth. Alternatively, compensatory mechanisms such as rapid replacement of ...

Mycoplasmas are important  avian  pathogens,  which  can  cause  both  respiratory  disease  and  synovitis  in  poultry  that  result  in  considerable  economic  losses  to  the  poultry  industry  all  over  the  world.  The  aim  of  this  study  was  to  determine  the  prevalence  of  Mycoplasma  gallisepticum  and  Mycoplasma  synoviae  infections  among  commercial  poultry  flocks  in ...

1. In large herbivores, the timing of breeding is important for females to hit peak plant protein levels. For males, the timing of reproductive effort is important to maximize the number of females they can mate during autumn rut in competition with other males. The latter depends on when most females are ovulating, but also on how other males with a different competitive ability are timing use...

Mycoplasma synoviae (MS) is an important avian pathogen that can cause both respiratory disease and joint inflammation synovitis in poultry, inducing economic losses to the Iranian chicken industry especially breeder farms. The aim of this study was to use the MS specific PCR and culture methods in order to detect of M. synoviae from breeder farms where located in Tehran province. A total of 47...

OBJECTIVE To determine prevalence of owner-directed aggression and identify associated environmental and genetic factors in English Springer Spaniels. DESIGN Prevalence survey. ANIMALS 1,053 adult English Springer Spaniels. PROCEDURE A mail survey was sent to 2,400 randomly selected owners of adult American Kennel Club-registered English Springer Spaniels. Dogs with a history of aggressio...

Current commercial broiler products are derived from the crosses of various strains at the primary breeder level. This study investigated chick development, yolk utilization, and early growth rate of males from 8 broiler breeder strains. These strains were a combination of both specialized and commercial-line products. At hatch, 110 male chicks per strain were weighed and wing-banded, and chick...

Effect of photoperiod on age and BW at attainment of mature semen production was examined in males of lines selected for high (HL) and low (LL) threshold BW at onset of lay, and in males of a commercial Cornish male line (MC), a commercial broiler breeder female line cross (BX), and a commercial layer cross (LX). Photoperiod treatments were: I, increasing natural spring light; and D, steadily d...