ABSTRACT The experiment was carried out with the objective of evaluating a methodology to estimate the angulation and equilibrium condition, relating them to gait score and the main diseases of the locomotion system in males and females of commercial broiler strains. A completely randomized experimental design in a factorial arrangement (2x2) was applied, consisting of two sexes and two genetic strains, with five replicates of 53 chickens each. The following characteristics related to broiler locomotion were studied: gait score (GS); incidence of Valgus (VAL) and Varus (VAR) deformities and of pododermatitis (POD); body angle relative the ground (ANG); equilibrium condition (EC); body weight (BW) and breast weight (BrW); and incidence of femoral degeneration (FD), tibial dyschondroplasia (TD) and spondylolisthesis (SPO). GS, and VAL and VAR were assessed inside a broiler house. Birds were then photographed to estimate ANG and EC. Birds were sacrificed at 42 days of age and analyzed for FD, TD, and SPO. Breast percentage was not influenced by sex or strain. Males showed better ANG than females, regardless of strain. Overall, the strains studied showed prostrated EC. The correlation between GS and the evaluated traits was low. There was a moderate to high association between EC and ANG both in males and females. GS showed low correlation with locomotion problems, and therefore, it is a poor indicator of skeletal diseases. On the other hand, the moderate to high correlations of ANG and EC with locomotion problems make them better indicators of bone diseases than gait score, which is possibly more related to EC and body posture than to bone pathologies.

ABSTRACT Three experiments were carried out to evaluate the levels of digestible valine in diets with reduced crude protein on the performance, carcass yield and muscle fiber diameter of male broilers during the pre-starter (1 to 8 d of age), starter (9 to 21 d of age) and grower phases (21 to 42 d of age). A total of 1,080 chickens in the pre-starter phase, 900 in the starter phase and 864 in the grower phase were distributed in a completely randomized design with six treatments, consisting of a control positive diet (C+) and diets with 2 percentage points (p.p.) reduction of crude protein level and five graded levels of digestible valine (Val), with six replicates of 30, 25 and 24 birds per experimental unit, respectively. The recommended level of TID Val in the low-protein diets for broilers in the pre-starter, starter and grower stages were 1.028; 0.905 and 0.789%, respectively. The reduction of 2 percentage points of the crude protein level in diets based on corn and soybean meal impaired (p ≤0.05) the feed conversion ratio in the starter and grower stages. Likewise, the reduced-protein diets decreased (p ≤0.05) muscle fiber diameter, but did not affect (p> 0.05) carcass and parts yields, or abdominal fat percentage at 42 days.

This study evaluated the effects of different sources of vitamin D and calcium levels on performance, egg quality and bone strength of hens in the second production cycle. A total of 384 Hy-Line W36 birds with 80 weeks of age were used, alloted into 3 x 4 factorial design (sources of vitamin D: cholecalciferol; 25(OH)D3 and 1.25(OH)2D3 x calcium levels: 2.85, 3.65; 4.45 and 5.25%) with four replicates and eight birds each. The performance was evaluated for three cycles of 28 days each, egg quality was evaluated in the last four days of each cycle and bone strength on the last day of the experimental period. There was no interaction (p > 0.05) between the different sources of vitamin D and calcium levels in all parameters evaluated. There was a quadratic effect (p < 0.05) of calcium levels in egg production and feed conversion (kg/kg and kg/dz), with better results at levels of 4.12%, 4.09% and 4.14%, respectively. Calcium levels had no effect (p > 0.05) in the egg weight and Haugh unit, but there was a linear increase (p < 0.05) in the percentage and eggshell thickness, in specific gravity and bone strength. The different sources of vitamin D influenced (p < 0.05) the egg production rate, feed conversion, egg weight and Haugh unit. Thus, the results of this study suggest that the recommended calcium level for laying on second cycle is between 4.09% and 4.14% and that the metabolites cholecalciferol and 25(OH)D3 improved the performance and egg quality. Regarding bone strength was improved as the calcium levels were increased in diets.

Morphological asymmetry has been described as a potential broiler welfare indicator, for interpreting the birds' ability to cope with the challenges that may affect its growth. The objective of this study was to evaluate the use of morphological asymmetry data to estimate broiler walking ability and welfare.dBroilers werefed diets supplemented or not with vitamin D. Toes were measured when birds were 42 and 49 days old using digital caliper.the left and right sides of the following four bilateral traits (tarsometatarsus length, outer toe length, mid toe length, and back toe length) were measured twice on intact alive birds by two different researcherh. Data from right and left sides were compared in the two treatments using the Student t-test, and Pearson's correlation was used to analyze the total asymmetry found as a result of the total sum of the differences in the measurements. Asymmetry data were comparedwith the total numberof leg lesions. Mid toe and tarsometatarsus asymmetry resultswere considered as actual fluctuating asymmetry, and presented normal distribution (Test of Kolmogorov-Smirnov, p >0.05). However, back toe and outer toe measurements were not normally distributed, as determined by the test of Kolmogorov-Smirnov (p <0.05), indicating anti-asymmetry; when comparing right with left limb,results were significantly different fron zero (t-Student, p <0.05) indicating directional fluctuating asymmetry.The welfare of broilers withwalking difficulty due to the presence of severe asymmetry in limbs is poor.

This study was conducted to determine the effect of the air temperature variation on the mean surface temperature (MST) of 7- to 35-day-old broiler chickens using infrared thermometry to estimate MST, and to study surface temperature variation of the wings, head, legs, back and comb as affected by air temperature and broiler age. One hundred Cobb® broilers were used in the experiment. Starting on day 7, 10 birds were weekly selected at random, housed in an environmental chamber and reared under three distinct temperatures (18, 25 and 32 ºC) to record their thermal profile using an infrared thermal camera. The recorded images were processed to estimate MST by selecting the whole area of the bird within the picture and comparing it with the values obtained using selected equations in literature, and to record the surface temperatures of the body parts. The MST estimated by infrared images were not statistically different (p > 0.05) from the values obtained by the equations. MST values significantly increased (p < 0.05) when the air temperature increased, but were not affected by bird age. However, age influenced the difference between MST and air temperature, which was highest on day 14. The technique of infrared thermal image analysis was useful to estimate the mean surface temperature of broiler chickens.

In the Brazilian meat production scenario broiler production is the most dynamic segment. Despite of the knowledge generated in the poultry production chain, there are still important gaps on Brazilian rearing conditions as housing is different from other countries. This research study aimed at analyzing the variation in bird skin surface as function of heat distribution inside broiler houses. A broiler house was virtually divided into nine sectors and measurements were made during the first four weeks of the grow-out in a commercial broiler farm in the region of Rio Claro, São Paulo, Brazil. Rearing ambient temperature and relative humidity, as well as light intensity and air velocity, were recorded in the geometric center of each virtual sector to evaluate the homogeneity of these parameters. Broiler surface temperatures were recorded using infrared thermography. Differences both in surface temperature (Ts) and dry bulb temperature (DBT) were significant (p<0.05) as a function of week of rearing. Ts was different between the first and fourth weeks (p<0.05) in both flocks. Results showed important variations in rearing environment parameters (temperature and relative humidity) and in skin surface temperature as a function of week and house sector. Air velocity data were outside the limits in the first and third weeks in several sectors. Average light intensity values presented low variation relative to week and house sector. The obtained values were outside the recommended ranges, indicating that broilers suffered thermal distress. This study points out the need to record rearing environment data in order to provide better environmental control during broiler grow-out.