Effect of different lighting sources on the performance of broiler breeder hens

The present study aimed to evaluate the effects of using light-emitting diode (LED) lamps versus incandescent/tungsten (Inc) bulbs on broiler breeder hens' productive performance during the brooding and rearing periods (25 weeks), as well as the first 15 weeks of production. A total of 46600 one-day-old Arbor Acres Plus breeder chicks were placed in eight enclosed houses and randomly/evenly divided into two groups (four houses for each group): birds raised under yellow LED lighting, and birds raised under orange Inc lighting. Several traits have been studied to determine productive performance, including body weight at different ages, body weight gain, feed consumption, feed conversion ratio, mortality rate, uniformity, age and weight at sexual maturity, egg number, egg production rate, egg number per bird, egg weight, and egg mass. According to the findings, using LED lighting instead of Inc lighting during the rearing period resulted in a significant improvement in all studied traits, and this positive effect continued until the production period, yielding excellent results for all studied production traits. LED lighting proved to be an effective source of lighting in broiler breeders' houses.(AU)

A Comparative Study of the Effect of Non-Antibiotic Feed Additives on Experimental Colonization of Salmonella Enterica Serovar Enteridis and Intestinal Pathomorphology in Broiler Chickens

The objective of this study was to evaluate the effect of eubiotics on the intestinal morphology of broilers. For this purpose, 125 birds were divided into six groups with two replicates each (10 birds in each replicate). Group A was given a Basal diet. All groups except group A were challenged with Salmonella enterica serovar Enteritidis. Group B was provided the basal diet, group C was fed a Probiotic-added diet; group D was fed a Prebiotics-based diet; group E was given essential oils plus the basal diet; and group F was provided with organic acids plus the basal diet. Two separate experiments were carried out for Salmonella recovery, checking the cecal tonsils and conducting an intestinal pathomorphic evaluation. Villus length, villus width, villus surface area, and crypt depth were measured by micrometry. There was an overall improvement (p<0.05) in intestinal morphometric parameters for all the treatment groups except for the negative control group, which showed the lowest villus height and villus depth values. Maximum villus height (p<0.05) of the duodenum was achieved by group E, which was fed a diet containing essential oils, whereas a maximum villus surface area index (p<0.05) was recorded for the birds of Group D, which were fed a diet containing prebiotics. Maximum villus height (p<0.05) and surface area index in ileum mucosa was recorded (p<0.05) in the birds of group D (treated with prebiotics). It is concluded that there is an overall increase in the gut histology of broilers fed non-antibiotic based feed.(AU)

Effect of Different Conditioning Temperatures and Times on the Pellet Quality, Performance, Intestinal Morphology, Ileal Microbial Population, and Apparent Metabolizable Energy in Broiler Chickens

This experiment was conducted for 42 days, and aimed to investigate the effect of conditioning temperature and time on feed quality, performance, jejunum morphology, ileal microbial population, and apparent metabolizable energy in broilers. According to the completely randomized design (CRD) in a factorial arrangement 2*3 (conditioning temperatures: 65 and 75 °C; conditioning times: 30, 60, and 90 second), 540 one-day-old male Ross 308 broilers were randomly distributed among six treatments with six replications, each replicate including 15 birds. Treatments included: 1) 65-30, 2) 65-60, 3) 65-90, 4) 75-30, 5) 75-60, 6) 75-90. The results showed that 60 seconds of conditioning at 75 °C increased the pellet durability index (PDI) in the starter diets (p<0.05). In the grower and finisher diets, groups (65-60) and (65-90) showed the highest PDI (p<0.05). Broilers fed diets conditioned at 75 °C for 60 s showed more body weight gain (p<0.05). On days 25 and 42, the highest villus height (VH) was observed in treatment (75-60), and 60 s steam conditioning increased crypt depth (CD) (p<0.05). At 75 oC, the number of goblet cells decreased, while their highest number was observed at 30 and 60 s on 25 d (p<0.05). Conditioning at 75 °C for 60 s enhanced the apparent metabolizable energy (AME) in broilers (p<0.05). In conclusion, 60 s conditioning at 75 °C improved the PDI of starter diets, performance, villus height, and AME, while the suitable temperature and pelleting time for grower and finisher diets were (65-60) and (65-90).(AU)

Inclusion of Stored Wheat in the Feed of Broilers Influences Intake, Growth Performance, Nutrient Digestibility, and Digesta Viscosity from 1-21 Days of Age

The objective of the current study was to examine the effect of replacing maize with new or stored wheat on the nutrient intake, digestibility, digesta viscosity, and growth performance of growing broilers from 1-21 days of age. For this purpose, 560 one-day-old male broiler chicks were randomly divided into seven experimental treatments, each with 8 replicates of 10 birds. The control diet was a corn soybean-based diet, while six other experimental treatments replaced the corn of the control diet with either 50% or 100% of new, 1.5 year, and 2.5-year-old wheat. The results showed that the replacement of corn with new wheat at 50% and 100% in the diet of broilers significantly reduced feed intake and body weight gain, and increased FCR (p<0.05) at week 3. Similarly, in the overall period of the starter phase (1-21 days), replacement of corn with new wheat at 50% and 100% in the diet of broilers significantly reduced feed intake, nutrient digestibility, and body weight gain, and increased digesta viscosity and FCR (p<0.05). Based on the findings of the current study, it is concluded that stored wheat successfully replaces corn and new wheat in the diet of broilers. Furthermore, stored wheat has a positive impact on feed intake, performance parameter, digesta viscosity, and nutrient digestibility as compared to new wheat.(AU)

Growth curves of broilers fed different nutritional relationships using the Gompertz model

The study aimed to evaluate performance and growth curves of broilers fed different nutritional relations. A total of 1,440 Cobb-500 male day-old chicks were assigned to eight treatments in a 2 x 2 x 2 factorial arrangement with six replicates of 30 birds each. The main factors were nutritional density (control and high), lysine source (HCl and sulfate), and calcium pidolate (presence and absence). Analyses were made for body weight gain (BWG), and feed conversion rate (FCR) at 21, and 42 days of age. The growth curves were adjusted by weighing a bird per plot every three days. Data for BWG were tested by ANOVA to evaluatethe effects of treatments and their interactions at 5% significance, and the Gompertz model was adjusted by NLS. Birds fed a high nutritional density had higher BWG and lower FCR. Calcium pidolate and different sources of lysine did not influence the FCR of broilers, however a triple interaction was evidenced for BWG at 1 to 42 days of age. The day with maximum gain adjusted by Gompertz of all treatments was at the 32ndday of age and the maximum weight (A) was around 5.85 kg.(AU)

Commercial Feed Diluted with Different Fiber Sources and Enzyme Product for Broilers: Growth Performance, Carcass and Gut Health

The dilution of commercial broiler feed with copra meal (CM), palm kernel meal (PKM) and cassava leaf meal (CLM) and enzyme supplementation was investigated. Two hundred and eighty 7-day old Cobb 500 broilers were fed commercial feed alone or diluted with the test ingredients with and without enzyme. There were no interaction effects (p>0.05) on feed intake (FI) and weight gain (WG). Poorer (p<0.05) feed conversion ratio (FCR) was observed on the diet diluted diets from 22-42 d, but this was restored (p>0.05) by enzyme supplementation. There was no interaction effect on final body weight (FBW). Diet dilution depressed FBW (p<0.05) but enzyme supplementation restored (p>0.05) this weight depression. Abdominal fat was lighter (p<0.05) on CLM compared to CM. There were no interaction effects (p>0.05) on the weight of gut segments and E. coli count. Heavier (p<0.05) liver, gizzard and intestine were observed on the test diets. Commercial feed dilution with CM, CLM and PKM at 100 g/kg for starter and 200 g/kg for finisher would be a viable option for smallholder broiler production. More research is needed into dilution levels and enzyme concentrations.(AU)

The Effects of Yucca Schidigera Extract and Multi-carbohydrase in Different Crude Protein Diets on Growth Performance, Nutrient Digestibility, Carcass Parameters and Excreta Noxious Gas Contents in Broilers

The scarcity and increase in the price of animal feeds have attracted the attention of nutritionists to address this issue. The inclusion of plant extracts and enzymes to protein-reduced diet could be a feasible strategy to reducing the feed cost. Therefore, the purpose of this study was to assess the impacts of Yucca schidigera extract and multi-carbohydrase in low crude protein (CP) diets of broiler on growth performance, nutrient digestibility, carcass metrics, and noxious gas levels in the excreta. A total of 480, 1-d-old ROSS 308 were randomly allocated into 4 dietary treatments, six replication, and 20 birds/cage. Phase 1, T1(CP 21%, ME 2,969 kcal/kg); T2 (CP 19%, ME 2,863 kcal/kg + 0.02% Yucca); T3 (CP 17%, ME 2,865 kcal/kg + 0.02% Yucca); T4 (CP 17%, ME 2,861 kcal/kg + 0.02% Yucca + 0.1% multi-carbohydrase). Phase 2, T1 (CP 19%, ME 3,086 kcal/kg); T2 (CP 17%, ME 2,977 kcal/kg + 0.02% Yucca); T3 (CP 15%, ME 2,978 kcal/kg + 0.02% Yucca); T4 (CP 15%, ME 2,978 kcal/kg + 0.02% Yucca + 0.1% 0.1% multi-carbohydrase). Although the addition of YS and multi-carbohydrase to the low CP diets on the growth performance did not improve, it revealed the positive result on the nutrient digestibility, carcass parameters, and noxious gas emission. Overall, broilers supplemented with YS 0.02% and multi-carbohydrase (0.1%) demonstrated the best production performances compared to the other treatment groups. Thus, a combination of YS and multi-carbohydrase could be added to the diets with low CP to boost broiler production performance.(AU)

Carbohydrase inclusion in a corn-soybean diet improves broiler growth performance

An experiment was conducted to evaluate the effect of diets with reduced energy level content, supplemented with carbohydrase, on broiler performance and the coefficient of metabolizability of nutrients. A total of 720 one-day-old male Cobb-500 chicks were distributed in a completely randomized design, with six treatments, eight repetitions of 15 birds each. The treatments were: (1) a positive control, basal diet to meet the requirements of broiler chickens (PC); (2) a negative control, basal diet with a reduction of 80 kcal kg-1 (NC); (3) NC + alphagalactosydase; (4) NC + xylanase; (5) NC + xylanase and alphagalactosydase, and (6) NC + enzymatic blend (alphagalactosydase, xylanase, pectinase and amylase). The nutrient digestibility was not improved by use of enzymes. At 7 days of age, the broilers which were fed diets supplemented with enzymes showed a lower feed intake (FI) and better feed conversion ratio (FCR) than the broilers fed on PC. Both the NC and enzymatic blend resulted in a worse performance of the broilers at 21, 35 and 42 days old. The use of alphagalactosydase and xylanase, isolated or in combination, in a corn-soybean meal-based diet is effective in improving the growth performance of broilers fed energy-reduced diets.(AU)

Reproductive and hormonal responses of two breeds of roosters fed diets containing chromium picolinate with or without vitamin C at high ambient temperature

This study evaluated the effects of chromium picolinate (CrPic) with or without vitamin C on the reproductive potentials of cocks raised under high ambient temperature. Four diets contained CrPic at 0.00 to 1.20 mg kg-1 without vitamin C and another four diets contained CrPic with 200 mg vitamin C each. A total of 192 White Leghorn and Noiler cocks (96 cocks each) were randomly assigned to the 8 treatments and replicated 4 times with 6 cocks per replicate in a 2 x2 x 4 factorial experiment. At the end of the sixteen weeks study, twelve birds per treatment were randomly sacrificed. The testes were carefully sampled, weighed and processed for estimation of daily sperm production using the homogenate method. The results revealed that the interactions of 0.40 mg CrPic kg-1 with or without vitamin C significantly (p < 0.05) influenced the gonadal and extra-gonadal weights, semen characteristics among the cocks while the daily sperm production and reproductive hormones were not negatively affected. This study, therefore, concluded that 0.40 mg CrPic kg-1 diet with vitamin C could significantly reduce the effects of heat stress on cocks raised under high ambient temperature without negatively impacting on their normal reproductive functions.(AU)

Effects of Supplementation of Zinc, Manganese, or Copper and Different Phytase Levels in Serum and Bone Acid and Alkaline Phosphatases of Broiler Chicks

The knowledge of biological trace minerals and phytase requirements for modern broiler genotypes is not established and the pressure to reduce their usage in animal feeding due to environmental issues is increasing. Here, the alkaline phosphatase (ALP) and tartarate-resistant acid phosphatase (TRAP) of the tibia and serum of broilers fed with diets containing various levels of phytase and reduced levels of zinc, manganese, and copper was evaluated. The experiment was performed using 1,200 male Cobb broilers raised according to standard commercial husbandry techniques. Data were analyzed as a 4×3 factorial arrangement with four concentrations of zinc (0.34, 0.49, 0.64, and 0.79 ppm), manganese (0.18, 0.43, 0.68, and 0.93 ppm), or copper (0.09, 0.12, 0.15, and 0.18 ppm) and three concentrations of phytase (0, 500, and 1,000 FTU/kg) for age periods of 1-21 and 36-42 days. While the dietary supplementation with copper did not induce a significant effect in bone tissue biochemical markers, serum TRAP activity of 42-day old broilers increased with higher copper levels. Increasing dietary zinc levels linearly increased ALP activity in tibia growth, suggesting that zinc is essential for longitudinal bone growth. Phytase significantly promoted the increase of TRAP and ALP activities, suggesting that manganese increased growth plate activity, accelerated calcification, and remodeled the newly formed tissue into trabecular bone. Although not every enzymatic activity was affected by the treatments, the phytase use, along with trace minerals, improved the animal response to the rapid growth required nowadays and provided the nutrients for adequate bone metabolism.(AU)

Identical thermal stress coupled with different temperature and humidity combinations affects nutrient digestibility and gut metabolites of laying hens

The present study investigated whether the same temperature-humidity index (THI) values under different conditions of air temperature and relative humidity (RH) would affect the thermoregulatory, nutritional, and behavioral responses of laying hens. One hundred twenty Hy-Line Brown laying hens (60-weeks-old) were divided equally in two environmental chambers: 26 °C with 70% RH (hRH75) and 30 °C with 30% RH (hT75) for 28 days. The two ambient environments (hRH75 and hT75) had an identical THI value of 75, calculated using an empirical formula for laying hens. Neither hRH75 nor hT75 affected rectal and body-surface temperatures and heart and respiratory rates. The concentration of volatile fatty acids in fecal excreta were altered by the thermal treatments. hT75 vs. hRH75 decreased the proportion of acetate and increased the proportion of propionate in fecal samples. hT75 vs. hRH75 lowered the digestibility of dry matter, crude protein, and neutral detergent fiber at 14 days. Thermal treatments did not affect heat stress-associated behavioral responses including feeding, drinking, panting, and wing elevation at any stage. Laying hens exposed to the same THI at different temperatures and RH exhibit equal physiological responses including rectal and body-surface temperatures, heart and respiratory rates, and behavioral responses. Nonetheless, high-temperature treatment (hT75; 30 °C and 30% RH) vs. low temperature treatment (hRH75; 26 °C and 70% RH) affects nutrient digestibility and gut metabolites, suggesting that there are negligible but discernable responses to temperature in the gut physiology.(AU)

Efficacy and Optimal Feeding Level of Rumex Nervosus Leaves on Blood Biochemistry, Carcass Characteristics, Productivity Indices, and Anticoccidial Indicators of Broiler Chickens Infected or Not Infected with Eimeria Tenella

O presente estudo investigou a eficácia e o nível ideal de alimentação de folhas de Rumex nervosus (RNL) em frangos de corte infectados e não infectados com Eimeria tenella . Em um planejamento fatorial de 2 (desafio coccidiano ou não) 5 (tratamentos alimentares), pintos de corte de 250 dias de idade foram distribuídos aleatoriamente em um dos dez grupos e criados por 28 dias. Foram investigadas medidas intestinais, características de carcaça, índices bioquímicos séricos, leucogramas, desempenho e indicadores anticoccidianos. Todos os parâmetros selecionados não foram significativos ( p>0,05) alterado pelas interações entre dieta experimental e desafio aos 7 dias pós-infecção, com exceção dos níveis séricos de albumina e globulina, bem como do índice anticoccidiano. Os frangos infectados apresentaram menor indicador de desempenho, menor eficiência de produção, baixos índices anticoccidianos, moela mais pesada, intestino delgado mais longo e mais pesado, ceco mais curto e maior proporção de eosinófilos em comparação com frangos não infectados. O RNL apresentou eficácia anticoccidiana marcante na dose de 5 g. O presente estudo descobriu que o pó da folha de Rumex nervosus apresentou eficácia preventiva anticoccidiana de leve a acentuada, dependente da dose, em frangos de corte. No entanto, mais estudos são necessários para compreender completamente os mecanismos anticoccidianos.(AU)

Effect of Turmeric (Curcuma Longa) on Duodenal Structure in Broiler Chickens

Supplementation of feed with turmeric (Curcuma longa) has been shown to be beneficial in poultry farming. The present study aimed at evaluating the effect of turmeric on the duodenal structure of broiler chickens during the first 42 days of life. A control and three treatment groups (turmeric powder added to feed at the following doses: E1 - 5; E2 - 10; E3 - 20 g/kg feed) were constituted (n = 8). Addition of turmeric powder in the feed resulted in an increase in intestinal villi height and a decrease in crypts depth in case of groups E1 and E2, while the villus height to crypt depth ratio generally did not differ significantly from the control. Turmeric also influenced the histological structure of the duodenum, as well as the presence of IL-6 and TNFα, as evidenced through staining. Addition of 0.5 and 1 % turmeric powder in the feed had evident results on body weight gain.(AU)

Effect of Housing Design and Location on Production and Economic Performance of Broiler Chickens during Summer in Botswana

Botswana experiences long, hot summer periods which negatively affect broiler productivity and results in economic losses. To determine these negative effects, two parallel broiler production studies were conducted in the North eastern (NE) and South eastern (SE) regions. In each region, three large scale commercial broiler farms were randomly selected based on similarities in bird management and housing systems. In each farm, one house type (Gable, Hoop and See-saw) was selected for long term flock monitoring (1 to 35 days) over three production cycles. Results showed that the production performance of the broilers in the SE region was superior to that in the NE region, with temperatures on being average higher in the NE than in the SE. The European Production Efficiency Factor (EPEF) was significantly higher (p0.05) between the regions at 9.0% and 7.4% for the NE and SE, respectively. In the NE, the Gable structure had the highest profitability and economic efficiency and was thus superior in comparison to the other house structures.(AU)

Effects of a monocomponent protease from Bacillus licheniformis on broiler performance, digestibility, and carcass yield

Two experiments were carried out to evaluate the effectsof protease addition to the diet of broilers at a higher level (1× or 2×) thanthe nutritional value proposed for the enzyme. The first experiment, 1280 day-old chicks (Cobb500®) were randomly allocated (randomized block design, 2×2+1 factorial arrangement),five treatments, eight replicates containing32 birds/replicate. Treatmentsconsisted: control diet without protease (CD); CD + 1× nutritional value of the enzyme (CDM1); CD + 2× nutritional value of the enzyme (CDM2); CDM1 + protease; and CDM2 + protease. The experimental period was 42 days. The mean weight (AFW), feed intake (FI), weight gain (WG), feed conversion, and carcass yield were evaluated. Significant differences were observed for AFW, WG, FI, abdominal fat yield, and feet percentage in the carcass. In the second experiment, 120 Cobb500®chicks at 14 days of age were allotted in a completely randomized design, 2×2+1 factorial arrangement, five treatments, six replicates withfour birds/replicate. The treatments were consistent with the first experiment. Significant improvements in the nitrogen balance wereobserved for the broilersthat received protease.The use of the enzyme tested is recommended with the recommended nutritional matrix, improving the zootechnical indices of broilers.(AU)

Threonine-to-lysine ratio in laying hens: physiological parameters and organ weight

The objective of this study was to evaluate the effect of threonine:digestible lysine ratio in the diet on the physiological variablesand weight of organs of light laying hens. Two hundred and ten 47 week-old Dekalb White laying henswere distributed in a completely randomized design, with five levels of threonine (0.507; 0.552; 0.597; 0.642 and 0.677%) and seven replicates of six birds each. The experimental period was 10 weeks, totaling 62 days and more eight days for the animals to adapt. The physiological parameters of cloacal temperature (CT), respiratory rate (RR) and average surface temperature (AST) were recorded weekly (7:00 am, 10:00 am, 1:00 pm, 4:00 pm, and 7:00 pm); after solid and water fasting,the birds were slaughtered to assess the absolute weight of the organs. The time of day influenced (p < 0.05) the physiological parameters RR and AST, and CT showed a significant effect (p < 0.05) of increasing levels of digestible threonine. The total weight of the pancreas, proventriculus and lung showed a significant effect (p < 0.05) of the increase in the levels of digestible threonine. The respiratory rate is affected by the levels of threoninein the diet. The 0.687% level promoted hypertrophy of the pancreas, proventriculus and lung, promoting more significant activity of these organs.(AU)

Dietary Inclusion of Pancreatin Enzyme on the Ileal and Fecal Digestibility of Nutrients in Layer-Type Cockerels

The current experiment aimed to evaluate the effects of Pancreatin supplementation at different levels on ileal and fecal digestibility in layer-type cockerels. A total of 480-day-old silver brown Hy-Line male chicks were randomly allocated into 5 treatments, 6 replicates (16 birds per pen) arranged in a completely randomized design. Pancreatin enzyme was supplemented on a basal corn-soybean meal-based diet at 0, 250, 500, 750, and 1000 mg/kg and was fed in two growth phases (starter and grower). The results indicated that at the end of the starter stage, except for 1000 mg/kg, dietary Pancreatin supplementation levels increased (p<0.05) the ileal crude protein (CP). Similarly, addition of Pancreatin increased (p< 0.05) apparent ileal amino acids (AA) digestibility (AIAAD) total means of AA (MTAA), means of indispensable AA (MIAA) and dispensable AA (MDAA) with the optimum performance on 250 mg/kg and 500 mg/kg. However, except for histidine and alanine which were negatively affected (p<0.05), and MIAA, MDAA, MTAA which were also positively affected, the addition level at 1000 mg/kg did not affect most of the AIAAD compared to the non-supplemented. Further, Pancreatin supplementation had no effect (p>0.05) on nitrogen digestibility (ND), nitrogen retention (NR), digestible energy (DE), apparent metabolizable energy (AME), dry matter digestibility (DMD), dry matter retention (DMR), and apparent metabolizable energy corrected for nitrogen (AME-n) on fed starter diet. On the other hand, at the end of the grower stage, dietary Pancreatin enzyme supplementation reduced (p<0.05) the ileal CP, MIAA, MDAA, MTAA, AIAAD, AME, AME-n, ND, NR, DE, DMD, and DMR in a dose-dependent manner. The rate of reduction was more marked on Pancreatin addition level 1000 mg/kg. In conclusion, Pancreatin supplementation at 250 mg/kg, 500 mg/kg, and 750 mg/kg improved AIAAD and ileal CP, especially at the young age. The rate of pancreatin enzyme effect was dependent on enzyme supplement level to the ileal CP and individual amino acid.(AU)

Effects of Lupin Kernel (Lupinus angustifolius) and Faba Bean (Vicia faba) on Growth Performance and Hepatic Fatty Acid Profiles in Broiler Chicks

This study was conducted to evaluate the effect of feeding lupin kernel and faba bean as an alternative to soybean meal on the growth performance, blood profiles, relative organ weight, and hepatic fatty acid composition of broiler chicks. A total of 525, 1-day-old Ross 308 male chicks were randomly assigned into five groups with seven replicates. The treatments consisted of five experimental diets; corn-soybean meal without lupin or faba bean (as control), diets with lupin 5% or 10%, and diets with faba bean 5% or 10%. The body weight (BW) and average daily gain (ADG) were not significantly different among the groups during starter period. However, BW and ADG of chicks fed diets with 10% lupin and faba bean were significantly higher than those of 5% lupin and faba bean during grower period (p<0.01). The feed conversion ratio was significantly lower in the group fed diets with 10% lupin and faba bean than the control during total rearing periods (p<0.001). There were no significant differences in blood profiles among the groups. As for the hepatic fatty acid composition, the levels of total polyunsaturated fatty acids and total ω6 in chicks fed lupin and faba bean were significantly higher than the control. It was suggested that dietary lupin and faba bean could enhance the incorporation of the beneficial fatty acids into liver fraction. In conclusion, supplementation of lupin and faba bean up to 10% can be used as an alternative to soybean meal in broiler diets.(AU)

Physical and Semen Characteristics of Mexican Creole Roosters in Summer and Autumn, at 19° North Latitude with a Constant Photoperiod

The objective of this study was to evaluate the effect of the seasons (Summer and Autumn), on live weight, body condition, mass motility, percentage of live spermatozoa, and sperm-cell concentration of Creole roosters (Gallus domesticus) from Mexico. Semen from 35-week-old Creole roosters was collected weekly during 10 weeks in Summer and Autumn, through the dorso-abdominal massage technique. Roosters were individually kept under a constant photoperiod (16 hours light:8 hours dark). The average live weight was 4.5% higher (p<0.05) in Autumn (2.78 kg) than in Summer (2.66 kg), therefore this variable increased with age (r = 0.85, p<0.05). Category 2 of body condition occurred (p<0.05) with higher probability than the others (0, 1 and 3), being practically the same (p>0.05) in Autumn (99.96%) and in Summer (99.81%). On average (and in weeks 1 and 3-10), the percentage of live spermatozoa was higher in Summer than in Autumn. Accordingly, the percentage of live spermatozoa decreased with age (r = -0.82, p<0.05). However, on average, sperm-cell concentration did not change between seasons (p>0.05). In conclusion, Mexican Creole roosters showed higher percentage of live spermatozoa in Summer than in Autumn. Therefore, it is advisable to select these animals of about 2.7 kg and reproduce them in Summer.(AU)

Relationship Between Pre-Slaughter Factors and Major Causes of Carcass Condemnation in a Broiler Slaughterhouse under Federal Inspection

This study aimed to investigate the relationship between pre-slaughter factors and major causes of total or partial carcass condemnation in a broiler slaughterhouse under federal inspection. Data on total and partial carcass condemnations between 2018 and 2020 were collected from 10 broiler farms supplying a slaughterhouse located in northern Paraná State, Brazil. The total sample comprised 2,562,642 birds. The pre-slaughter factors analyzed were age at slaughter, stocking density, weight at slaughter, feed conversion, and mortality.Associations between causes of condemnation and pre-slaughter factors were analyzed using a generalized linear model with negative binomial distribution, a generalized linear model with quasi-Poisson distribution, and a generalized linear mixed model with Poisson distribution. Total carcass condemnations were mostly due to repugnant appearance (48.67%) and arthritis (26.56%), whereas partial carcass condemnations were mainly due to arthritis (31.02%), bruising (27.97%), and myopathies (15.18%). Mean age and stocking density were the pre-slaughter factors that most contributed to increasing total and partial condemnation rates, indicating that reducing stocking density and age at slaughter might be important strategies for minimizing economic losses associated with carcass condemnation.(AU)