P. C. Pozza

Efeito dos teores de cálcio para poedeiras semipesadas durante a fase de pré-postura e no início da postura

The effect of feeding increasing calcium levels for semi-heavy laying hens during the prelay phase and its effects in the four subsequent weeks were evaluated in this trial. Two hundred and eighty-eight Isabrown birds with 16 weeks of age were allotted to a complete randomized design with four treatments, eight replicates and nine birds per experimental unit. The corn and soybean meal-based diets were formulated to meet the bird nutrient requirements, with the exception of calcium levels. The experiment lasted six weeks, when the birds were fed four prelay diets with increasing calcium levels (0.6, 1.2, 1.8, and 2.4%) in the period from 16 to 17 weeks of age. During the four subsequent weeks, a diet with 3.8% of calcium was fed for all birds. No treatment effect on weight gain, age at first egg and ash content in the shell of first egg was observed, however linear effect on calcium level retained in the shell was detected. In the four subsequent weeks, the different calcium levels fed in the prelay phase did not affect feed intake, egg production, feed:gain ratio, weights of eggs and shell, shell thickness and calcium concentration in the shell. Shell weight in relation to egg weight, shell weight per unit of area surface and ash content in the shell were affected linearly by treatments. The calcium levels in the prelay diet not affect egg internal and external quality during the first four weeks of laying. The 0.6% calcium nutritional level is recommended for semi-heavy laying hens in the prelay phase.

Níveis de valina digestível para suínos machos castrados dos 15 aos 30 kg

O objetivo deste trabalho foi o de avaliar niveis de valina digestivel para suinos machos castra- dos, dos 15 aos 30 kg de peso. No primeiro experimento, para determinacao do balanco de nitrogenio, foram utilizados 20 suinos, machos castrados, com peso inicial de 22,88±1,19 kg, distribuidos individualmente em gaiolas de meta- bolismo, em delineamento experimental de blocos ao acaso, constituido de cinco tratamentos (0,60; 0,67; 0,74; 0,81 e 0,88% de valina digestivel) e quatro repeticoes. No segundo experimento, de desempenho, foram utilizados 40 suinos, machos castrados, com peso inicial de 15,49±0,06 kg, submetidos aos mesmos tratamentos, repeticoes e delineamento experimental utilizados no primeiro experimento. A relacao N retido:N absorvido apresentou resposta quadratica, indicando um nivel otimo de valina digestivel de 0,748%. A excrecao total de N apresentou efeito quadratico em funcao dos niveis de valina digestiveis, sendo reduzida ate o nivel de 0,730% de valina digestivel e a partir deste nivel a excrecao de N aumentou novamente. A eficiencia de utilizacao de valina, para ganho de peso reduziu de forma linear a medida que aumentaram os niveis de valina digestivel nas racoes, e ao utilizar o modelo linear response plateou obteve-se a reducao deste parâmetro ate 0,790% de valina digestivel. Conclui- se que o nivel de 0,748% de valina digestivel foi o mais adequado, ao se considerar o N retido: N absorvido, para suinos machos castrados dos 15 aos 30 kg de peso.

Typification of Factors Related to Milk Production and Its Impact on the Sanitary Quality of Milk

Aiming at identifying and characterizing the dairy production systems regarding the hygienic and sanitary practices in milking on the sanitary quality of milk, 32 properties were analyzed through the data collection by means of a semi-structured questionnaire. The collected data were analyzed by multivariate statistical analysis, using the Principal Component Analysis (PCA) and analysis of Ascending Hierarchical Classification Cluster (CHA). Firstly, a cluster analysis was used for forming groups of variables. Through the groups formed was sought to obtain the explanatory variables through the PCA. Three PCA were obtained, which were named according to the variables of greatest effect in the analysis. The groups were called PCA-1: Equipment and contamination; PCA-2: Milking Technology; PCA-3: Scale of production. These results enabled the representation of the different characteristics of the production systems through cluster analysis, where for each PCA was performed a Cluster analysis, always with five groups of dairy production systems being formed with similar characteristics within each group. The formation of the groups enabled to identify that the performance of techniques and hygienic-sanitary managements of milking is more related to the age and producer’s education, linked to time in the dairy business.