ABSTRACT The objective of this study was to analyze the effect of environmental factors on egg production curve traits in broiler breeders. The weekly egg production records of birds collected from four different flocks were used to estimate the egg production curve parameters using the Compartmental function (y = A(1 − exp−b(t − d))exp−ct). The coefficient of determination (R2) obtained by the model was 0.98. Least squares analysis of variance indicated that the environmental factors such as hatchability and flock had significant effects on egg production curve traits. The highest correlation was observed between the weekly potential maximum yield and yield at the beginning of laying, whereas the lowest correlation was found between the weekly potential maximum production and production after peak yield. Associated factors with the increasing slope of egg production curves had a negative correlation with the decrease after peak. The correlation analysis showed that peak production had a negative and significant relationship with production towards peak and time to reach peak production, while there was a positive and significant correlation with the slope decrease after peak yield. The Compartmental function can be used as an alternative model to predict egg production traits in broiler breeders.

ABSTRACT The objective of this study was to determine whether the type of bedding materials (sand, wood shavings, and paper) and of two chemical amendments (lime and bentonite) could interfere with litter quality (moisture, pH, and total bacterial counts), thereby influencing also the growth performance and the development of intestinal traits and cecum microbiota of chickens. Two hundred and seventy male Ross 308 broiler chickens were randomly assigned into nine treatment groups with three replicates per treatment. Broiler productive parameters, relative weight of different intestinal segments, content of cecal total bacterial counts (total aerobic bacteria, Lactobacilli, and coliforms), as well as litter moisture, pH, and total aerobic bacteria and coliforms counts, were assessed. Litter material, per se, did not significantly affect the productivity parameters at the end of the experimental period (42 days) with the exception of protein efficiency. A significant trend was found among treatments with regard to weight gain and feed intake, with lower performance in birds on sand beddings. Litter pH was relatively homogenous between bedding types and amendments, but the moisture was significantly lower when sand was used. Litter type did not influence the relative weight of the different intestinal segments; however, the type of amendment affected the relative jejunum weight, which was increased in bentonite-treated litter. The use of lime and bentonite treatments may be helpful to decrease the differences in litter moisture associated with particular bedding materials. The tested amendments do not interfere with the productive performance of birds.

Objetivo. Este estudio se realizó durante la estación de invierno en la granja de ganado rural del distrito de Sargodha, Pakistán, con el fin de definir el estado de macrominerales en el plasma sanguíneo de vacas lactantes y secas de raza Desi. Materiales y métodos. Veinte vacas lactantes y veinte vacas secas fueron utilizadas y se analizó el plasma para el Ca, Mg, Zn, Cu y Fe utilizando un espectrofotómetro de absorción atómica. Resultados. En las vacas lactantes, la concentración de Ca en plasma fue menor que en las vacas secas (6.8 frente a 7.6 mg/dl, p<0.001), mientras que la concentración de Mg fue similar entre las lactantes y las vacas secas. La concentración plasmática de Zn en las vacas lactantes fue mayor que en las vacas secas (0.78 frente a 0.60 mg/L, p<0.01) y resultó inferior al rango normal en ambos grupos. Nivel de plasma de Cu en vacas lactantes fue inferior al de las vacas secas (0.56 vs a 0.76 mg/L, p<0.001) y fue inferior al rango normal sólo en las vacas lactantes. Las vacas lactantes resultaron en mayor concentración de Fe plasmático en comparación con las vacas secas (3.8 frente a 2.6 mg/l, p<0.01). Conclusiones. A partir de los resultados, se puede concluir que el nivel de minerales observados satisface las necesidades de los rumiantes y el nivel plasmático de diferentes minerales se ve afectado por las etapas fisiológicas de las vacas.

Objective. This study was conducted during winter season at rural livestock farm of district Sargodha, Pakistan, in order to define the macrominerals status in blood plasma of lactating and dry Desi breed cows. Material and methods. Twenty lactating and twenty dry cows were used and their blood plasma was analyzed for Ca, Mg, Zn, Cu and Fe using atomic absorption spectrophotometer. Results. In lactating cows, the plasma Ca concentration was lower than dry cows (6.8 vs. 7.6 mg/dl, p<0.001), while Mg concentration was similar between lactating and dry cows. Plasma Zn concentration in lactating cows was higher than dry cows (0.78 vs. 0.60mg/l, p<0.01) and it resulted lower than the normal range in both groups. Plasma Cu level in lactating cows was lower than dry cows (0.56 vs. 0.76 mg/L, p<0.001) and it was lower than the normal range only in lactating cows. Lactating cows resulted in higher plasma Fe concentration compared to dry cows (3.8 versus 2.6 mg/L; p<0.01). Conclusions. From our findings, it can be concluded that the observed minerals level meets the needs of ruminants and the plasma level of different minerals is affected by the physiological stages of cows.