Keel Bone Damage in Laying Hens-Its Relation to Bone Mineral Density, Body Growth Rate and Laying Performance.

Keel bone damage is an important animal welfare problem in laying hens. Two generations of four layer lines, differing in phylogenetic background and performance level and kept in single cages or floor pens were weighed and scored for keel bone deformities (KBD) during the laying period. KBD, keel bone fractures (KBF) and the bone mineral density (BMD) of the keels were assessed post mortem. For BMD, relationships to laying performance and body growth were estimated. Caged hens showed more deformities, but fewer fractures and a lower BMD of the keel bone than floor-housed hens. White-egg layers had a lower BMD (0.140-0.165 g/cm2) and more KBD than brown-egg layers (0.179-0.184 g/cm2). KBF occurred more often in the high-performing lines than the moderate-performing ones. However, in the high-performing lines, BMD was positively related to total egg number from 18 to 29 weeks of age. The adult body weight derived from fitted growth curves (Gompertz function) had a significant effect (p < 0.001) on keels' BMD. The study contributes to the understanding of predisposing factors for keel bone damage in laying hens. It showed that the growth rate has a rather subordinate effect on keels' BMD, while the BMD itself greatly affects KBD.

Growth performance and carcass characteristics of Improvac-treated male pigs compared with barrows.

The present study assessed the effects of using Improvac (Pfizer Animal Health, Germany) on growth performance and meat characteristics in cross-bred male pigs. In addition average daily weight gain of immunised and surgically castrated males was estimated in order to demonstrate differences in growing patterns in these two treatment groups. The study was carried out in two identical batches. Pigs within batches (n = 446) were allocated to two different treatment groups: immunisation (IM) versus surgical castration (CM). Within treatment groups pigs were randomly assigned to two different diets (low- and high-lysine diet) in order to examine interactions of growth performance and castration technique. Vaccination was performed on the day of entry to the fattening unit and four to six weeks prior to slaughter. At the second vaccination IM-pigs showed significantly lower body weights than the control group (p < 0.05) in both batches. Throughout the whole fattening period CM-pigs tended to have a higher feed intake than IM-pigs while IM-pigs had a significantly lower (better) feed conversion ratio than CM-pigs (p < 0.05).The different lysine content of the diets had no coherent effect on any of the growth performance parameters analysed. Immunised pigs of both feeding groups and in both batches showed a tendency towards a lower carcass weight, back fat values and dressing percentages than surgically castrated pigs.The castration technique had no significant effect on meat quality parameters such as drip loss, shear force or cooking loss while intramuscular fat content (IMF) in immunised pigs fed high-lysine diets (IM(high)) tended to be higher than IMF in immunised pigs fed low-lysine diets (IM(low)). This effect was not seen in surgical castrates in either batch. Immunisation against GnRH offers a good approach to produce taint-free pork while ensuring boar-like growth for a large part of the fattening period.

[Passive immunization in neonatal piglets in natural rearing--effects of birth order, birth weight, litter size and parity]. / Untersuchungen zur passiven Immunisierung neugeborener Ferkel bei natürlicher Aufzucht--Einflüsse von Geburtsreihenfolge, Geburtsgewicht, Wurfgrösse und Wurfnummer.

603 neonatal piglets (German Landrace) were investigated for passive immunization affected by birth order, birth weight, litter size and parity. Concentrations of immunoglobulins in the blood serum of piglets on the first day of life served as measure for passive immunization. Blood samples were drawn at 12, 18 and 24 hours post partum. Quantitative measurements of immunoglobulin classes were carried out by radial immunodiffusion. There was a significant effect of birth order, because of the rapid changes in colostrum composition between onset of birth and the last piglet of each litter. The effect of birth weight was only partly significant and different for the immunoglobulin classes. There was no significant effect of litter size on passive immunization. Parity had a significant positive effect on IgG- and IgA-concentrations in sow's colostrum with litter two to six, parity 1 and 2 lead to highest IgM concentrations in the blood serum of piglets.