Specifically, the purpose of this study was to determine (1) whether brood parasites are successful in other species' broods as measured by survival and size of parasites and (2) whether parents have evolved a mechanism to detect and remove brood parasites from their broods as measured by differential culling rates
Breeding for mastitis resistance is becoming increasingly important because of its effect on farm economy and animal welfare (lower productivity, discarded milk, lower selling prices, higher culling rates
and higher veterinary costs).
layers, breeders and broilers), poultry production system categories, age of birds and incidence rates of morbidity, mortality, case fatality and culling rate
in commercial poultry farm chickens infected with HPAIV (H5N1).Whereas Figure 1 portrays the spatial allocation of the different chicken farms infected in the study area belonging to FAO poultry production system 2 and 3.
Therefore, when the culling rate
is [[rho].sub.D] = 0.1, the total living population after 250 days is 62.10% of the initial one while when [[rho].sub.D]= 0.8 the total living population after 250 days is 86.07% of the initial one.
, although not significantly different, showed a slight numeric advantage among sand users.
Good housing conditions for cows and management practices to control health problems may lead to a reduced involuntary culling rate
of sows 13 13 Body weight (kg) Breeding (d) 136.00 135.95 D 110 178.50 182.18 Breeding-110 d (change) 42.50 (b) 46.22 (ab) Backfat thickness (mm) Breeding (d) 19.32 1 9.1 8 D 110 20.72 21.27 Breeding-110 d (change) 1.40 2.09 Body length (cm) Breeding (d) 113.90 115.00 D 110 121.55 122.18 Breeding-110 d (change) 7.65 7.18 Lactation Body weight (kg) 24 h post farrowing 164.72 165.68 Weaning 174.11 (a) 173.45 (a) Post farrowing- 9.39 (a) 7.77 (a) 21 d (gain) Breeding-21 d 39.72 37.50 postpartum (gain) Backfat thickness (mm) 24 h post farrowing 21.06 20.32 Weaning 18.94 18.73 0-21 d (gain) -2.12 -1.59 Breeding -21 d (gain) 0.56 -0.45 Average feed intake (kg/d) 5.99 5.77 Weaning to estrus interval 5.29 5.27 Culling rate
(%) 38 7 Treatment Criteria 3,300 3,400 Gestation No.
The selection and handling after purchase of these animals can greatly affect the level of health problems and culling rates
in expanding dairies.
Prices were still very attractive,``It is unlikely that such a high culling rate
will be maintained in 2003,'' she said.
For each time point (parity), we used the Cochran-Armitage test to examine the association of sow cumulative culling rate
with body weight at d 109 of gestation of parity 1.
Even under good management conditions, herds that fill with purchased heifers normally experience a 20-30 percent culling rate
the first year, sometimes higher.
This is possible only if cows with the G/G genotype have a higher culling rate
. But what is the cause of such high culling rate
, which leads to decrease of G allele frequency in dairy herds compared with domestic low yielding cows such as Yakut cattle?