Effect of growth selection on morphology in Pirenaica cattle

Twelve variables were identified to define morphology in 109 calves sired by eight Pirenaica bulls widely used in artificial insemination. The effect of selection for weight at 210 days of age (W210) was detected from the regression coefficient between the 12 variables and the selection index for W210 used in the breeding plan. Unbiased estimates of the genetic correlated responses on the morphology were obtained without previously estimating the genetic correlation among traits. In Pirenaica cattle, selection for W210 increased slaughter live weight, chest depth and corporal length. The expected changes on height (withers, back and rump), rump width and thoracic perimeter were lower but positive and statistically significant.

Phenotypic, genetic and environmental parameters for traits related to femur bone integrity and body weight at 42 days of age in a broiler population

Intense selection among broilers, especially for performance and carcass traits, currently favors locomotion problems and bone resistance. Conducting studies relating to development and growth of bone tissue in broilers is necessary to minimize losses. Thus, genetic parameters were estimated for a broiler population's phenotypic traits such as BW at 42 d of age (BW42), chilled femur weight (CFW) and its yield (CFY), and femur measurements: calcium, DM, magnesium, phosphorus, and zinc content; breaking strength; rigidity; length; and thickness. Variance components were estimated through multitrait analyses using the restricted maximum likelihood method. The model included a fixed group effect (sex and hatch) and additive and residual genetic random effects. The heritability estimates we obtained ranged from 0.10 ± 0.05 to 0.50 ± 0.08 for chilled femur yield and BW42, respectively, and indicated that the traits can respond to the selection process, except for CFY, which presented low-magnitude heritability coefficients. Genetic correlation estimates between breaking strength, rigidity, and traits related to mineral content indicated that selection that aims to improve the breaking strength resistance of the femur is highly correlated with mineral content. Given the genetic correlation estimates between BW42 and minerals, it is suggested that in this population, selection for BW42 can be performed with greater intensity without affecting femoral integrity.

Dietary levels of lysine for male broilers from 23 to 36 days of age: performance and body composition

One thousand and fifty (1,050) Ross male broilers from 23 to 36 days of age were used to evaluate the dietary effects of levels of lysine. It was used a random block design with 5 levels of digestible lysine (0.95; 1.00; 1.05; 1.10 and 1.15%). Each level was applied to seven replicates and the experimental unit was composed of 30 birds. Diets were offered in seven replicates and the experimental unit was represented by 30 birds. Weight gain, feed intake, feed conversion, carcass traits, cut yields, composition and deposition of body nutrients were evaluated. The concentration of 1.09% of digestible lysine optimized performance without significant effects on feed intake. Carcass traits and cut yields had no significant differences among levels of lysine. On the other hand, there was a quadratic effect on carcass weight, which was the best at the level of 1.07% of digestible lysine. On crude protein content of the empty body, the best response was observed at the level of 1.10% of dietary lysine. This same level corresponded to a quadratic response in the deposition of water from carcass and empty body. The level of digestible lysine for better performance, chemical composition and body nutrient deposition in broilers from 23 to 36 days of age is between 1.07 and 1.10%.

Digestible lysine and organic zinc for male broiler from 1 to 11 days of age: performance and body composition

This study evaluated levels of digestible lysine and organic zinc for male Ross strain broilers from 1 to 11 days of age. It was used 1,050 chicks distributed in randomized block design, in 5 × 2 factorial scheme, with seven repetitions of 15 birds per experimental unit. The dietary concentrations of digestible lysine were 0.90; 1.00; 1.10; 1.20; and 1.40% combined with 43 and 253 ppm zinc chelate. The diets contained 2,965 ± 18 kcal/kg of apparent metabolizable energy (AME) and 21.48 ± 0.18% of CP. It was determined chemical composition, protein, lipid, mineral and water depositions on carcass and empty body. There was no interaction among the factors digestible lysine and organic zinc. Effect of zinc concentration increase was observed on greatest deposition of body fat, indicating that there is interference in lipid metabolism of the birds in the studied phase. The most pronounced effects resulted from the dietary inclusion of lysine. There was a linear effect on reconstituted body weight as a response to the increase of dietary lysine, which suggests equal or superior requirement to the greatest studied level. However, the deposition of water and protein on the carcass had a quadratic increase, characterizing higher muscle mass accumulation up to the levels 1.25 and 1.27 of this amino acid in the diet. Considering the studied strain, broiler chickens from the first to the 11th days of age require 1.28 ± 0.01% of digestible lysine, according to the deposition of muscle mass.

Fuzzy modeling of broiler performance, raised from 1 to 21 days, subject to heat stress

ABSTRACT Given the need to obtain systems to better control broiler production environment, we performed an experiment with broilers from 1 to 21 days, which were submitted to different intensities and air temperature durations in conditioned wind tunnels and the results were used for validation of afuzzy model. The model was developed using as input variables: duration of heat stress (days), dry bulb air temperature (°C) and as output variable: feed intake (g) weight gain (g) and feed conversion (g.g-1). The inference method used was Mamdani, 20 rules have been prepared and the defuzzification technique used was the Center of Gravity. A satisfactory efficiency in determining productive responses is evidenced in the results obtained in the model simulation, when compared with the experimental data, where R2 values ​​calculated for feed intake, weight gain and feed conversion were 0.998, 0.981 and 0.980, respectively.

Protein levels and environmental temperature effects on carcass characteristics, performance, and nitrogen excretion of broiler chickens from 7 to 21 days of age

This trial was conducted to evaluate the utilization of low-protein diets formulated based on the ideal protein concept for broiler chickens from 7 to 21 days of age reared at different environmental temperatures. Nine hundred male Cobb-500® chickens were used. At day seven chicks were distributed according to a completely randomized design in a 3 x 3 factorial with four replications of 25 birds each. It was used three crude protein levels in the diet (21.5; 20.0 and 18.5%) and three environmental temperatures (low, thermoneutral and high). The performance, carcass characteristics (yield and chemical composition), and nitrogen ingestion and excretion were assessed. There was no significant interaction among the factors for the evaluated variables. Environmental temperatures affected differently chicken performance. High environmental temperature resulted in lower weight gain and higher wing fat percentage, whereas cold temperature resulted in higher feed conversion. on the other hand, low-protein diets decreased weight gain, breast yield, nitrogen excretion and influenced breast and wings chemical composition. Birds reared at high environmental temperature showed lower nitrogen intake and excretion. The results showed that the decrease in protein levels from 7 to 21 days of age contributed to lower nitrogen excretion in broiler chickens, but impaired performance and carcass characteristics independent of rearing temperature.

Energy and lysine for broilers from 44 to 55 days of age

An experiment was conducted to evaluate the performance and carcass yield of broilers at 55 days of age fed diets with different levels of metabolizable energy and lysine. Evaluated data of performance were weight gain, feed intake, energy intake, lysine intake, caloric conversion and feed conversion. Carcass assessment was performed based on data from carcass yield, breast weight, whole wings, whole legs, back, head + neck, feet and abdominal fat. A 3 x 3 factorial arrangement was used, with 3 levels of metabolizable energy (3,200; 3,400 and 3,600 kcal ME/kg) and 3 lysine levels (0.95%; 1.05% and 1.15%). There was no interaction between the two factors. Nevertheless, increasing levels of metabolizable energy improved weight gain (745 g; 841 g and 910 g, respectively) and feed intake was higher in broilers receiving the diets with 3,200 and 3,600 kcal ME/kg. Overall performance was not affected by lysine levels. Feed conversion values were 2.69, 2.42 and 2.14 for birds fed diets with 3,200; 3,400 and 3,600 kcal ME/kg, respectively. Carcass yield and breast weight increased with higher levels of energy and lysine in the diets.

Effect of sodium gluconate on performance, carcass characteristics, and intestinal morphometry of broilers from 22 to 42 days of age

O presente estudo teve por objetivo avaliar o efeito da utilização de níveis crescentes do gluconato de sódio sobre o desempenho, o rendimento de carcaça e de partes e a morfometria da mucosa intestinal de frangos de corte de 22 a 42 dias de idade. Foram utilizados 1200 frangos de corte da linhagem Cobb, distribuídos em um delineamento inteiramente casualizado, envolvendo cinco tratamentos (0,00; 0,10; 0,20; 0,30 e 0,40% de gluconato de sódio) com oito repetições de 30 aves cada parcela. As variáveis foram submetidas à análise de variância e em caso de significância estatística foram realizadas análises de regressão pelos modelos polinomial e quadrático. A inclusão do gluconato de sódio não afetou o desempenho e o rendimento de carcaça e de partes. Entretanto, exerceu efeito benéfico sobre a morfometria da mucosa intestinal do duodeno e do jejuno.

Sunflower meal for broilers of 22 to 42 days of age

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Alkaline ribonuclease activity in maternal serum and in serum of newborns from birth up to thirty days of age. A study made with full-term appropriate-, full-term small- and preterm appropriate-for-gestational-age infants

We have studied the alkaline ribonuclease (RNase) activity in maternal serum and serum of full-term small- (T-SGA), full-term appropriate- (T-AGA) and preterm appropriate-for-gestational age (PT-AGA) newborns. A significantly lower level of RNase was observed in T-AGA and T-SGA newborns on the 30th day of age and in PT-AGA newborns on the 15th and 30th days of age, as compared to other T-AGA, T-SGA and PT-AGA groups of infants at birth. RNase activity was significantly higher in cord blood than in the maternal blood in all categories studied. Moreover, in preterm newborns, RNase activity in cord blood was significantly higher in those presenting a lower gestational age. We did not observe any significant difference in RNase levels in the cord blood of newborns from the 3 categories studied. The same results were observed concerning maternal blood. We, therefore, conclude that RNase activity in cord blood or in maternal blood is not a very statisfactory indicator of fetal malnutrition.

Estimates of direct and maternal genetic effects for weights from birth to 600 days of age in Nelore cattle

Estimates of direct and maternal variance and heritability for weights at each week (up to 280 days of age) and month of age (up to 600 days of age) in Zebu cattle are presented. More than one million records on 200 000 animals, weighed every 90 days from birth to 2 years of age, were available. Data were split according to week (data sets 1) or month (data sets 2) of age at recording, creating 54 and 21 data sets, respectively. The model of analysis included contemporary groups as fixed effects, and age of dam (linear and quadratic) and age of calf (linear) effects as covariables. Random effects fitted were additive direct and maternal genetic effects, and maternal permanent environmental effect. Direct heritability estimates decreased from 0.28 at birth, to 0.12-0.13 at about 150 days of age, stayed more or less constant at 0.14-0.16 until 270 days of age and increased with age after that, up to 0.25-0.26. Maternal heritability estimates increased from birth (0.01) to a peak of 0.14 for data sets 1 and 0.07-0.08 for data sets 2 at about 180-210 days of age, before decreasing slowly to 0.07 and 0.05, respectively, at 300 days, and then rapidly diminished after 300 days of age. Permanent environmental effects were 1.5 to four times higher than genetic maternal effects and showed a similar trend.

Estimates of covariance functions for growth from birth to 630 days of age in Nelore cattle

Weight records of Brazilian Nelore cattle, from birth to 630 d of age, recorded every 3 mo, were analyzed using random regression models. Independent variables were Legendre polynomials of age at recording. The model of analysis included contemporary groups as fixed effects and age of dam as a linear and quadratic covariable. Mean trends were modeled through a cubic regression on orthogonal polynomials of age. Up to four sets of random regression coefficients were fitted for animals' direct and maternal, additive genetic, and permanent environmental effects. Changes in measurement error variances with age were modeled through a variance function. Orders of polyno-mial fit from three to six were considered, resulting in up to 77 parameters to be estimated. Models fitting random regressions modeled the pattern of variances in the data adequately, with estimates similar to those from corresponding univariate analysis. Direct heritability estimates decreased after birth and tended to be lowest at ages at which maternal effect estimates tended to be highest. Maternal heritability estimates increased after birth to a peak around 110 to 120 d of age and decreased thereafter. Additive genetic direct correlation estimates between weights at standard ages (birth, weaning, yearling, and final weight) were moderate to high and maternal genetic and environmental correlations were consistently high. © 2001 American Society of Animal Science. All rights reserved.

The effects of up to 240 days of tacrolimus therapy on the gingival tissues of rats - A morphological evaluation

Background: Tacrolimus, an immunosuppressive drug used in organ transplantation, has been reported not to induce gingival overgrowth. However, prevalence studies are limited, and the methods used for assessing gingival overgrowth varies among studies. Objective: The purpose of this study was to evaluate the effects of up to 240 days of tacrolimus therapy on gingival tissues of rats. Materials and methods: Rats were treated for 60, 120, 180 and 240 days with daily subcutaneous injections of 1 mg/kg body weight of tacrolimus. After histological processing, the oral and connective tissue, volume densities of fibroblasts (Vf), collagen fibers (Vcf) and other structures (Vo) were assessed in the region of the lower first molar. Results: After 60 and 120 days of treatment with tacrolimus, gingival overgrowth was not observed. The gingival epithelium, connective tissue, as well as the values for Vf, Vcf, and Vo were similar to those of the control rats (P > 0.05). After 180 and 240 days of the treatment, gingival overgrowth was associated with a significant increase in the gingival epithelium and connective tissue as well as an increase in the V f and Vcf (P < 0.05). Conclusions: Within the limits of the experimental study, it may be concluded that the deleterious side effects of tacrolimus on the gingival tissues of rats may be time-related. © 2007 Blackwell Munksgaard All rights reserved.

Effect of plasma and/or yeast extract on performance and intestinal morphology of piglets from 7 to 63 days of age

The objective of this study was to evaluate the effect of diets supplemented with plasma and/or yeast extract on performance (daily weight gain [DWG], daily feed intake [DFI] and feed conversion [FC]) and intestinal morphology of piglets from 7 to 63 days of age. A total of 288 piglets aged 7 days and weighing 2.57±0.05 kg were studied. A randomized block design consisting of four experimental diets, six repetitions and 12 piglets per experimental unit was adopted. The pre-starter I (7 to 21 days), pre-starter II (22 to 35 days) and starter I (36 to 49 days) diets were supplemented as follows: control diet (CD): no plasma or yeast extract; plasma (PL) diet: addition of 6%, 4% and 2% plasma; yeast extract (YE) diet: addition of 6%, 4% and 2% yeast extract; plasma + yeast extract (PL+YE) diet: addition of 3%, 2% and 1% plasma and yeast extract each. From 50 to 63 days of age all piglets received the same diet. No difference in performance was observed from 7 to 21 days and from 7 to 28 days of age, whereas DWG was higher from 7 to 35 days in piglets receiving the PL+YE diet (268, 278, 271 and 288 g/day for CD, PL, YE and PL+YE, respectively). From 7 to 49 days and from 7 to 63 days, DWG (330 and 519 g/day, respectively) and DFI (307 and 647 g/day) were higher in animals receiving the PL-YE diet when compared with those consuming CD (DWG: 295 and 486 g/day; DFI: 266 and 594 g/day). No significant differences in intestinal morphology were observed between piglets receiving the different diets. The combination of plasma and yeast extract elevates DWG, but does not affect the intestinal morphology of piglets from 7 to 63 days of age. © 2013 Sociedade Brasileira de Zootecnia.

Maternal-calf relationships and their influence on calves up to 120 days

Objectives. To research parental behavior and measure the weight of Nelore and Guzerat calves up to 120 days of age, collecting data from birth up to the first lactation. Materials and methods. Seven different corporal positions were considered to obtain specific data for each of the following categories: time to stand (TP), time to intend to feed after standing (TPTM), weight at birth (PN), weight at 120 days (P120), and time in contact with the calf (TCC). Additionally, independent variables were also evaluated, organized by class: weight at birth (CPN), number of calvings (CNP), order of calving in relation with the herd (CLPR), time of calving (CHP), and finally, hindering to feed (CTAT). Results. There was a significant result in favor of the Nelore race over the Guzerat race. The statistical averages for Nelore and Guzerat were: Time to stand averaged 71 and 153 minutes; time to intend to feed after standing, 39 minutes for Nelore and of 114 minutes for Guzerat. For variable weight at 120 days, Nelore reached an average of 122 kg, and Guzerat 109 kg. For the time in contact with the calf variable there was no significant variance between races. Conclusions. Results showed the superiority of the Nelore race, considering it better adapted to local environmental conditions.