Feed Withdrawal Period Research Articles

Current Knowledge on the Transportation by Road of Cattle, including Unweaned Calves.

Transport conditions have the potential to alter the physiological responses of animals to the psychological or physical stress of transport. Transportation may introduce multiple physical and psychological stressors to unweaned calves and adult cattle, including noise, overcrowding, food and water deprivation, extreme temperatures, commingling with unfamiliar animals, handling by unfamiliar humans, and being placed in a novel environment upon arrival. Apart from these factors, the type of road and even driving skill may affect the welfare of animals. One of the concerns regarding cattle transport is that the handling and marketing of animals prior to a journey may lengthen the period of feed withdrawal. Furthermore, feed withdrawal can impact animal welfare through hunger and metabolic stress. Transportation is also associated with a decrease in animal performance as well as an increase in the incidence of bovine respiratory disease. It is well established that the transportation of cattle is a stressor that causes a quantifiable response; however, excessive stress during transport resulting in physiological or pathological changes can be reduced with best management practices. The objective of this review was to analyse the available scientific literature pertaining to the transport by road of cattle, including unweaned calves.

The Effect of Vitamin C and E Supplementation into Drinking Water on Carcass Characteristics, Meat Quality and Intestinal Microflora During Pre-Slaughter Feed Withdrawal in Broiler Chickens

This study investigates the effects of adding vitamin C and E to the drinking water on carcass characteristics, meat quality and intestinal microflora populations in broiler chickens during the 10-h pre-slaughter feed withdrawal (FW) period. As study materials, forty male broilers at the age of 42 days were used. The broilers were randomly divided into four groups: Control (non-vitamin, NV), vitamin C (1000 mg/L, VC), vitamin E (500 mg/L, VE) and vitamin combination (1000 mg/L VC+500 mg/L VE, VCE). In the study, vitamin additions didn’t affect carcass characteristics, visceral weights and the pH values of the digestive system (P>0.05). The addition of VC and VE increased the weight of the Bursa of Fabricius, and the addition of VE increased the weight of thymus (P<0.05). Additions of vitamin decreased tendency of carcass contamination (P<0.01) and increased pH45min and pH24h of thigh meat and pH24h of breast meat (P<0.05, P<0.01, P<0.01, respectively). While a* color intensity of breast and thigh meat increased with all vitamin supplements, L* and b* values of thigh meat decreased (P<0.01). Vitamin supplements, especially VE, reduced the drip loss of breast and thigh meat (P<0.05) and the pathogenic microorganism populations of intestinal contents (P<0.01). As a result, it is thought that the addition of 500 mg/L vitamin E to the drinking water of broiler chickens exposed to the pre-slaughter fasting period will be beneficial to improve meat quality and reduce intestinal pathogenic microorganism load. However, more extensive experimental studies are needed.

Effect of chamomile (Matricaria chamomilla L.), linden (Tilia cordata Mill.), and green tea (Camellia sinensis L.) aqueous extract administration in the drinking water during pre-slaughter feed withdrawal period in broiler chickens.

Feed withdrawal (FW) and other pre-slaughter stressors have detrimental effects on the meat quality of broiler chickens. Herbal extracts can be used for their sedative effects to reduce the harmful impacts of pre-slaughter stress on broiler chickens. This study aimed to investigate the effect of chamomile (CAE), linden (LAE), and green tea (GAE) aqueous extracts (AE) in drinking water during the pre-slaughter FW period on the meat and liver quality, serum corticosterone level, and some cecal microorganisms of broilers. A total of 450 male and female 42-day-old chickens were allocated to a completely randomized design with five treatment groups and two sexes in six replicates, 12 birds (six male and six female) for each replicate. Treatment groups were chickens offered ad libitum feed and drinking water (control, CT), broilers exposed to FW for 10h before the slaughter with unsupplemented drinking water (FW), with drinking water supplemented 50ml/L CAE, LAE, and GAE. Chickens that experienced FW had lower (P < 0.001) slaughter body weight, carcass, gastrointestinal tract (GIT) and inner organ weights, and GIT length (P = 0.002). However, the dressing percentage was higher (P < 0.001) in FW and AE groups than CT group. The FW increased (P < 0.001) the ultimate pH of thigh meat compared with the CT group. The FW also decreased (P = 0.026) the lightness (L*) value of thigh meat of broilers, although CAE and LAE did not change the L* value compared with the CT group. Similarly, the redness (a*) value of thigh meat was lower (P = 0.003) in chickens exposed to FW but was not affected by GAE administration. However, FW or AE did not impact the serum corticosterone level and cecal microbial loads in broiler chickens. The obtained result showed that CAE, LAE, or GAE can be used in drinking water to reduce the harmful effects of FW on the meat quality of broiler chickens.

Processing weights of chickens determined by dual-energy X-ray absorptiometry: 3. Validation of prediction models

Dual-Energy X-ray Absorptiometry (DEXA) has been shown to predict the processing weights of the carcass and cut-up pieces of the chicken. This study aimed to validate models to predict processing weights using DEXA that were previously developed. An experiment was conducted with broilers grown up in 80 floor pens randomly subjected to one of five dietary treatments. On day 41, all birds were weighed, seven were randomly selected per pen, and their weights were recorded. After a feed withdrawal period, five selected birds per pen were transported to a processing plant, and the rest of the birds were fed again. The carcass was weighed before and after chilling for one hour. The chilled carcass was cut up, the weights of each commercial piece were recorded (breast fillet, tenders, wings, leg quarters, total white meat, and ready-to-cook parts), and the corresponding unchilled weights were calculated. On day 43 or 44, the other two birds selected per pen were weighed, DEXA-scanned without fasting, and their fasted weights were determined by applying a previously developed equation. Predicted processing weights were obtained by entering DEXA-reported values into a set of models previously developed. All the data were adjusted to the same BW basis. The pen mean observed processing weights and the DEXA-predicted ones were used to validate the models. The linear regression between predicted and observed values was calculated, and the R2 was used as a precision index. The parallelism of the predicted and observed response curves across dietary treatments, and the model prediction error and accuracy were determined. The validation criteria were based on the validation R2, the change in R2 from development to validation, the parallelism of response curves, and the prediction accuracy. The validation R2 of all tested models predicting the weight of cut-up pieces was > 0.84, and their prediction errors were ≤ 5.85 %, except for the model predicting the weight of the wings (prediction error > 10 %). All traits showed parallel trends when the response curves across treatments obtained with the DEXA-predicted values or the processing plant data were compared. In conclusion, all models but the one predicting the weight of wings satisfied the evaluation criteria and were validated, supporting the use of DEXA to determine the processing weights of broilers and its application to the study of nutrition interventions to improve breast meat production.

Chicken liver morphology as affected by feed withdrawal time and dietary aflatoxins

ABSTRACT 1. An investigation was conducted on the effects of aflatoxin (AFL) contaminated diets and feed withdrawal periods from 0 to 12 h in broiler chickens at 28 d of age. Both factors can potentially affect liver colour and can cause failure at veterinary inspection in the slaughterhouse. 2. A total of 240, one-d-old female Cobb 500 broiler chickens were fed a common corn-soy pre-starters (d 1 to 7) and then either a non-contaminated control (CON) or feed with 1 ppm AFL (AFL) from d 8 to 28. The inoculum of AFL had 792 ppb of aflatoxin B1, 35 ppb of aflatoxin B2 and 219 ppb of aflatoxin G1. On d 28, all broilers were weighed and euthanised for necropsy following three different feed withdrawal time periods (0, 6 or 12 h), in a 2 × 3 factorial arrangement. 3. Body weight gain, liver weight and liver fat content decreased as feed withdrawal lengthened, whereas FCR and gallbladder weight increased (P≤0.05). AFL-fed birds had reduced body weight and proportion of liver fat and increased FCR, liver and gallbladder weights (P≤0.05). 4. Livers from fed broilers (0 h withdrawal) showed more lightness (L*) and yellowness (b*) than livers of broilers from 6 or 12 h withdrawal (P≤0.05). The L* and redness (a*) values of livers from broilers fed diets COB were lower than those from AFL fed broilers (P≤0.05). 5. Prolonging pre-slaughter feed withdrawal decreased liver L* whereas feeding AFL increased liver b*. These findings can be used to support veterinary assessment in slaughterhouses as shackled birds move on line through the inspection site. Since chicken liver is a valuable organ and an indicator of animal health, attention must be paid to these differences to ensure consumer safety.

절식 시간에 따른 육계의 소낭 내 Salmonella 오염도, 소화관 길이, 혈액 성분, 계육 품질에 미치는 영향

In this study, we aimed to evaluate the impact of different feed withdrawal periods (2, 3, 4, 5, and 6 h) on <i>Salmonella</i> contamination in the crop, intestinal weight, and blood parameters of broilers before harvesting. A total of 100 broilers (initial live weight 1.906±0.06 kg) were randomly assigned to the same five treatment groups and broilers had access to water but no feed before catching. Feed withdrawal times were 2, 3, 4, 5, and 6 h prior to slaughter. Measurements included live weight, pre-slaughter weight, carcass weight, weight of gastrointestinal tract. In addition, <i>Salmonella</i> and <i>Campylobacter</i> contamination in the crop, serum biochemical profiles, counts of leukocytes, erythrocytes, and platelets, and meat quality were assessed. The results demonstrate that carcass weight, blood corticosterone, meat pH, meat color, and water holding capacity did not differ based on the feed withdrawal time. Carcass yield increased as the withdrawal time increased, but the weights of the crop, proventriculus, jejunum, ileum, and rectum were significantly reduced by 6 h (<i>P</i>&lt;0.05). <i>Salmonella</i> counts were the lowest in the crops subjected to 6 h of feed withdrawal (<i>P</i>&lt;0.05). Shear force was highest in chicken breast meat after 6 h of feed withdrawal (<i>P</i>&lt;0.05). However, when the feed was withdrawn after 6 h, the shear force increased, but it did not affect the sensory characteristics in consumers, and the <i>Salmonella</i> count also decreased and had a reduction effect on contamination during slaughter. These findings can serve as reference data for setting the feed withdrawal time.

Evaluation of existing poultry processing and marketing in the wet market of Gazipur city in Bangladesh

The poultry selling and processing practices followed in the poultry wet markets of Bangladesh are always being overlooked unknowingly. The research was conducted to observe the existing scenario of poultry selling and processing practices at the selected wet markets located in the Gazipur City Corporation of Bangladesh. A total of 43 poultry selling shops were randomly selected and interviewed using a semi-structured questionnaire. It was surprising to observe the absence of female personnel and involvement of few (6.9%) people over the age of 50 years in the wet markets. All the persons engaged in poultry selling and processing had no institutional training. The shops found to be abstained from following some important practices such as feed withdrawal period, isolation of diseased birds, ante and post mortem inspection. The proper bleeding time (1-2) min was recorded in 58.2% cases. The killing cone was recognized as the best device in terms bleeding time. The 72.1% of the outlets never cleaned the carcass prior to deliver the customers. The absence of ante- and post-mortem inspections may cause a great threat of disease outbreak. Taken together, the poultry selling and processing practices followed in the wet market needs to be assessed carefully to deliver safe and quality meat to the customers. In addition, organizing basic training on pre-slaughter management and processing for both seller and processor and also ensuring the regular ante- and post- mortem inspection could improve the present situation in order to produce quality poultry meat.&#x0D; Progressive Agriculture 31 (3): 205-217, 2020

EFFECTS OF ADDING ACETIC ACID AND FEED WITHDRAWAL PERIOD ON GROWTH PERFORMANCE OF BROILER CHICKENS DURING THE SUMMER SEASON

The present study evaluates the effects of feed withdrawal period and addition of acetic acid in drinking water on growth performance, physiological measurements, carcass traits, carcass chemical composition, intestinal microbial and economic efficiency of broiler chicks during the period of 22 to 42 days of age under Egyptian condition. A total number of 270 of Cobb broiler chick one day old were randomly assigned to six groups and fed a basal diet through the experimental period. The groups T1 (control), T2, T3, T4, T5 and T6 were fed ad libitum, fasting 8 hours, addition of 6% acetic acid, fasting 8 hours with addition of 6% acetic acid, addition of 8% acetic acid and fasting 8 hours with addition of 8% acetic acid, respectively. The highest (P<0.05) final weight and weight gain were recorded for T5 group. While group T2showed the lowest (P<0.05) value. The highest (P<0.05) averages of daily feed intake were reported by T1, T5 and T3 groups. While, group T2 had (P<0.05) the lowest daily feed intake. The best feed conversion ratio (P<0.05) was recorded by the groups T2 and T4. Mortality rate was significantly the highest for the control. Blood serum traits are significantly affected by feeding dietary treatments within normal rage. Dressing carcass weight of T5 birds was significantly the highest compared to T2. Abdominal fat weight was significantly the highest for the control. The total bacteria account was (P<0.05) higher in birds treated acetic acid and the coliform bacteria was significantly lower. European production efficiency factor (EPEF) increased significantly for all treatments except the control. These results concluded that addition of acetic acids (6 and 8%) with feed withdrawal (8 hours at 22-42 days of age) in drinking water during summer season have a positive effect on growth performance of broiler.

Nutrient digestibility and physiological implication of feed withdrawal periods and ascorbic acid supplementation in growing pigs under tropical environment

A study was conducted to evaluate nutrient digestibility and physiological impact of feed withdrawal periods and ascorbic acid supplementation in pigs reared in tropics. Unsexed, 8 weeks old mixed breed pigs (54) with mean body weight of 5.5±0.2 kg were arranged in a 3×3 factorial layout. The pigs were grouped on weight equalization into 9 treatments of 3 replicates with 2 pigs per replicate. Vital signs data were obtained on weekly basis. Three pigs from each treatment group were selected at tenth week and arranged in clean disinfected metabolic cages for a 7 day adaptation and a 5 day quantification of feed intake and faecal output. Faeces collected were dried in a forced air cabinet and analysed for proximate composition. About 5 ml blood sample was collected, 2.5 ml each was placed in EDTA and sterile bottles for haematological and biochemical indices evaluation. Data obtained were subjected to a 2-way analysis of variance. The feed withdrawal period had no impact on nutrient digestibility. Ascorbic acid supplementation significantly influenced excreted faeces, faecal dry matter output, dry matter and ash digestibility. Neutrophils increased with increasing period of feed withdrawal while lymphocytes decreased significantly with increasing period of feed withdrawal. Feed withdrawal period and ascorbic acid supplementation had no influence on serum biochemical parameters. It can be concluded that feed withdrawal periods influenced neutrophil, lymphocyte and neutrophil-lymphocyte ratio whereas ascorbic acid enhanced nutrient digestibility of pigs but had no impact on vital signs and blood indices.

The Effects of Using Oregano and L-Carnitine on Second Phase Laying Performance Parameters of Force Molting Programs in Laying Hens

This study was carried out to use Oregano leaf and L-carnitine as an&#x0D; alternative feed additives in alfalfa flour or low Sodium-Calcium (Na-Ca) diet&#x0D; and to determine their effect on second phase laying period after force molting&#x0D; in commercial laying hens. A total of 1170 birds were divided into 13 groups&#x0D; which were further subdivided into 6 replicates having 15 birds in each. A&#x0D; negative control group (K) which was&#x0D; neither forced molted nor provided with any feed additive substances in their&#x0D; diets Moreover, other three treatment groups (M: Marbel powder, A:&#x0D; Alfalfa, F: Low Ca-Na diet), were&#x0D; forced molted and one withhold feeding group was used for the study; the forced&#x0D; molted groups were supplied L-carnitine (C)&#x0D; (100 ppm) and Oregano leaves (O) (5%)&#x0D; as a feed additive in designed individual diets (MC, AC, FC, MO, AO, FO )&#x0D; alone and in combination (50 ppm; 2.5%) in groups (MCO, ACO, FCO). All hens were feeding with commercial feeds during&#x0D; the second laying phase.The&#x0D; trial was 98 days after 22 days of forcing stage. Performance&#x0D; parameters (except egg quality) were measured during 14 days periods. In the&#x0D; results, eggs yield values were found significantly higher (P&amp;lt;0.01) among&#x0D; the treatment groups over control group. It was concluded that supplementing&#x0D; L-carnitine and Oregano leaves could be used as an alternative feed additives&#x0D; in alfalfa meal during feed withdrawal period and their combination also showed&#x0D; a positive impact on laying performance in laying hens.&amp;nbsp;

Use of a maltodextrin-based feed with a lysozyme product to alter bacterial in the ileum of market-aged broilers

Poultry meats can become contaminated with pathogenic bacteria through digesta leakage during processing. Reducing the bacteria load in digesta of market-aged broilers prior to processing reduces the incidence of fecal contamination at the processing plant. A lysozyme product was incorporated in a maltodextrin-based feed offered during the pre-shipping feed withdrawal period to reduce bacteria in ileal contents of market-aged broilers. Twenty 36-day-old broilers were randomly allocated to each of 16 pens. For a 9 h period each pen was randomly assigned to one of the following treatments: no feed, maltodextrin-based feed with a lysozyme product (Inovapure) added at 0, 10, or 20 g per kg of feed. Feed consumption was determined and a minimum of 3 birds were randomly selected from each pen and euthanized. The ileal contents were removed and weighed. Samples were analyzed forClostridium perfringens, aerobic bacteria, Enterobacteriaceae, E. coli, and coliform numbers using standard culturing techniques and next generation sequencing was performed to determine population shifts. Bacteria counts were transformed to log10 colony forming units (cfu) and analyzed as a completely randomized design. The data from next generation sequencing was analyzed as a 3 × 5 factorial design using Proc Mixed of SAS. Lysozyme did not affect feed consumption nor were the weight of ileal contents different for birds fed maltodextrin-based feeds compared to birds on traditional feed withdrawal. E. coli /coliforms and Enterobacteriaceae plates had no signs of bacterial growth. The number of Clostridium perfringens and aerobic bacteria in the ileal contents of market-aged broilers was not different between treatments using the traditional culturing techniques. Next generation sequencing was a useful alternative to traditional culture techniques as results revealed that bacilli were reduced and clostridia increased for the 20 g lysozyme treatment. Addition of lysozyme to a maltodextrin based feed did not change overall numbers of bacteria but was effective in altering the participants in the bacteria community in ileal contents of market-aged broilers.

Influence of feed withdrawal period on growth performance of broiler chickens under high ambient temperature

This experiment was conducted to evaluate that effect feed withdrawal period on growth performance of broiler chickens. 180 chicks at one day of age were divided into three treatments groups with 6 replicates of 10 birds. First group of chicks as control group was fed basal diets (commercial broilers diets 23% crude protein as starter; 21% crude protein as grower and 19% crude protein as finisher, respectively, until 35 days of age). The second groups fed the same control diets but the feed withdrawal for one hour per day at night. The third group fed the same control diets but the feed withdrawal for two hour per day and one hour at afternoon and one hour at night (from 8-35 days of age). While feed consumption was not different among these three groups, both final body weight and body weight gain were higher in chicks feed withdrawal for 2 h/d; however feed conversion ratio was decreased. Feed withdrawal 2h/d decreased abdominal fat compared with control group while, carcass, muscles, liver and gizzard weights were not affected. Furthermore, feed withdrawal decreased plasma total cholestrol, while neither glutamate oxaloacetate transaminase (GOT) nor glucose were not affected. These results suggested that feed withdrawal had positive effects on growth performance and plasma lipid profiles in broilers chickens.

Risk factors for bruising and mortality of broilers during manual handling, module loading, transport, and lairage

Multiple factors can affect the risk of bruising and mortality of broilers during loading, transport, and lairage. The risk factors affecting the percentages of broilers in each load that were “dead-on-arrival” (DOA) or bruised were studied from records provided by a processing plant, by undertaking direct observations during on-farm loading and then carrying out multivariable analyses. Selected loads between 2014 and 2015 from seven producers were included in the study. The median DOA per load was 0.13% (Q1 = 0.06, Q3 = 0.25, n = 212), the median total duration from loading to unloading was 8.6 h, and the external temperature ranged from −22 to 22 °C. Although it was not possible to adequately characterise thermal conditions within each load, the analysis indicated that the main risk factors for increased mortality were in spring and winter, an increased duration between loading and end of lairage, and a period of feed withdrawal before loading longer than 6 h. The risk of mortality increased with the weight of the birds and with an increase in rearing mortality. No relationships were found between the manner in which the broilers were handled and the percentages of DOAs or bruised birds.

Energy utilization in cattle with steady state and non-steady state methods: the importance of thermal neutrality

The efficiency by which animals utilize dietary energy is fundamental to the cost of production for protein of animal origin and to the carbon footprint an animal industry has. Hence, the development of cost effective methodology for determining these measurements of efficiency is important. The objective of the present study was to investigate the use of infrared thermography in a rapid, non-steady state method for measuring energy loss in cattle. Data from 241 yearling bulls and steers as well as heifers and mature cows are presented. Infrared images were collected following a 24h feed withdrawal period. The infrared thermal response in these animals was significantly ranked (P < 0.03) with conventional measurements of feed efficiency using residual feed intake values for animals demonstrated to be within a thermal neutral zone. When animals were not within a thermal neutral zone there was no significant ranking. The data suggests that the use of a non-steady state approach using infrared thermography for identifying metabolic efficiency in animals may be a more rapid and less expensive method for identifying differences in energy utilization. The data also demonstrates the importance of maintaining thermal neutrality when measuring metabolic efficiency irrespective of the methodology.

Descriptive sensory quality of Kenya’s indigenous chicken meat from different ecotype- clusters reared under an intensive system

Indigenous chicken (IC) in Kenya performs a major food security and socio-economic function for most households, especially of the rural poor. The trend has been to move from rearing IC on free-range systems to more intensive and semi intensive systems. This study was conducted by use of Quantitative Descriptive Analysis (QDA) and the Just About Right (JAR) scale scores to quantify the appeal of the IC meat reared under intensive systems. The IC used in the study had been obtained from Taita, Kakamega and Narok ecotype clusters kept under the intensive system at Indigenous Chicken Improvement Programme (INCIP) unit at Egerton University. During the intensive rearing, the chickens were given the same treatment in terms of feed, disease control at all the stages and water was given ad-libitum. The chickens were slaughtered at the same age and only cocks were used as control for sensorial differences accruing due to sex. Five cocks from each ecotype cluster were slaughtered after a feed withdrawal period of 8-10 hours and their meat prepared by boiling for sensory evaluation after ageing on ice for 3-6 hours. A trained panel of tasters (13-15) was used to evaluate the descriptive and JAR sensorial quality of indigenous chickens’ meat from the breast and thighs. One commercial broiler (Kenbro) was used as a control. Results showed that there was significant effect at P<0.05 of the ecotype of the IC on its meat aroma, flavour and brown colour intensity. The JAR scale showed that the consumers’ scores for the colour, flavour, juiciness, tenderness of indigenous chicken was ‘just about right’ compared to broiler which was described by colour as too light, flavour too strong, too juicy in terms of expression of juiciness and too tender with regard to texture. The Principal Component Analysis results showed that there were two principal components (colour and texture) that accounted for 55.4 % and 11.6% and 53.9 and 19% for both descriptive scores and JAR scores for IC meat, respectively. This study indicates sensorial differences among the Kenyan Indigenous chicken ecotypes (of different genetic characteristics) under intensive systems and demonstrates significant difference among various attributes from the commercial broiler. Key words : Descriptive, sensory evaluation, Kenyan Indigenous chicken, ecotype cluster, intensive system

Effects of short and extended fasting periods and cattle breed on glycogenolysis, sarcomere shortening and Warner-Bratzler shear force

The effects of short (three hours) and extended (24 hours) feed withdrawal periods and three cattle breeds on muscle energy metabolism, sarcomere length, and meat quality were investigated. Brahman (Br), Nguni (Ng), and Simmental (Sm) bulls were subjected to ante-mortem feed withdrawal of three hours (Br3, n = 10; Ng3, n = 10; and Sm3, n = 10) or 24 hours (Br24, n = 10; Ng24, n = 10; and Sm24, n = 10). M. longissimus was used as the reference muscle for sampling. pH, and temperature was recorded at 1, 2, 3, 6, 9, and 24 hours post mortem. Samples for energy metabolites were removed at 3, 6, 9 and 24 hours post mortem. Glycogen, glucose-6-phosphate and creatine phosphate concentration were determined at each time interval as glycosyl units after hydrolysis. Samples to determine sarcomere length were removed at one and three days post mortem. Homogenates of the samples were placed under a 31,000 magnification microscope and sarcomere lengths were measured. Warner-Bratzler shear force (WBSF) was measured with an Instron meter at 1, 7 and 14 days post mortem. Glycogen was lower for Br24 and Ng24. There were no differences in glucose-6-phosphate, rate of creatine phosphate decline, average sarcomere length, or WBSF for Br24 and Ng24 compared with Br3 and Ng3. There were no differences for WBSF between Br3, Ng3 and Sm3. Glycogen concentration was higher for Sm24 compared with Sm3; glucose-6-phosphate was lower for Sm24 compared with Sm3; and the rate of creatine phosphate decline was higher for Sm24 compared with Sm3. Average sarcomere length was shorter and WBSF was higher for Sm24 compared with Sm3. The effect of prolonged ante-mortem feed withdrawal on tenderness is breed specific. Warner-Bratzler shear force was affected significantly by an extended feed withdrawal period in Simmental cattle only. Keywords: Acidification, creatine phosphate depletion, fasting, hypometabolism, meat tenderness

Impact of litter Salmonella status during feed withdrawal on Salmonella recovery from the broiler crop and ceca

Research was conducted to evaluate the impact of litter Salmonella status during feed withdrawal on Salmonella recovery from the crop and ceca following feed withdrawal. In 4 experiments, pens of broilers in separate rooms were challenged with marker strains of either Salmonella Montevideo or Salmonella Heidelberg. Three d post challenge, a 12-hour feed withdrawal was initiated, and one pen of broilers was switched between rooms for each Salmonella serotype. In experiments 3 and 4, non-challenged broilers also were added to the Salmonella challenge pens. The litter of each pen was sampled before and after the feed withdrawal period, the broilers euthanized, and the crop and ceca aseptically removed for Salmonella isolation. Results showed that only the challenge Salmonella serotype was recovered from the litter in challenge pens where broilers were not moved, while both Salmonella serotypes were recovered from the litter of the switched pens. Salmonella was recovered from 56/80 crops and from 66/80 ceca of challenged broilers that remained in the challenge pens. The challenge Salmonella serotype was recovered from 50/80 crops and from 60/80 ceca, and the switched pens' litter Salmonella serotype was recovered from 19/80 crops but not from the ceca in broilers challenged with Salmonella and then switched between pens. For experiments 3 and 4, Salmonella was recovered from 19/40 crops and from only 2/40 ceca from the non-challenged broilers placed into the Salmonella challenge pens. The results from broilers that were switched between Salmonella challenge pens indicate that the recovery of Salmonella from the crop of broilers following feed withdrawal (on Salmonella-contaminated litter) appears to depend mainly on the initial challenge Salmonella (62%) and less on the litter Salmonella (24%) status during the feed withdrawal period. In contrast, only the initial challenge Salmonella was recovered from the ceca (79%) from broilers that remained in challenge pens or were switched between Salmonella challenge pens. However, when non-challenged broilers were placed into the Salmonella challenge pens and commingled during the 12-hour feed and water withdrawal period, it was possible to recover the pen litter Salmonella from the ceca at a low level of 5% (2/40).

Effects of stocking density and daily feed withdrawal periods on the performance of broiler chickens in a semi-arid environment.

Unsexed Ross 308 broilers were raised under three stocking densities (30, 35, and 40kg BW/m2) and three daily feed withdrawal periods (0, 8, and 12h daily) during a 42-day production period. The effects of stocking density and feed withdrawal on growth performance and carcass characteristics were investigated. The feed intake of broilers raised at the stocking density of 30kg BW/m2 was higher than those of broilers reared at 35 and 40kg BW/m2, but broilers raised under the different stocking densities did not differ significantly in 42-day body weight, body weight gain, feed conversion ratio, and mortality rate. Forty-two-day body weight, body weight gain, and feed intake were reduced as the duration of feed withdrawal increased, but feeding program affected neither feed conversion ratio nor mortality rate. There was a stocking density effect on thigh percentage while feeding program influenced breast, back, wing, neck, liver, gizzard, and heart percentages. There were stocking density × feed withdrawal interaction effects on feed intake during the starter and grower periods. It is suggested that for profitable broiler production in the tropics stocking density of 40kg BW/m2 and daily feed withdrawal for 8h from 7 to 35days of age be considered.

Identification of risk factors for Campylobacter contamination levels on broiler carcasses during the slaughter process

Campylobacter carcass contamination was quantified across the slaughter line during processing of Campylobacter positive batches. These quantitative data were combined together with information describing slaughterhouse and batch related characteristics in order to identify risk factors for Campylobacter contamination levels on broiler carcasses. The results revealed that Campylobacter counts are influenced by the contamination of incoming birds (both the initial external carcass contamination and the colonization level of caeca) and the duration of transport and holding time that can be linked with feed withdrawal period. In addition, technical aspects of the slaughter process such as a dump based unloading system, electrical stunning, lower scalding temperature, incorrect setting of plucking, vent cutter and evisceration machines were identified as risk factors associated with increased Campylobacter counts on processed carcasses. As such the study indicates possible improvements of the slaughter process that can result in better control of Campylobacter numbers under routine processing of Campylobacter positive batches without use of chemical or physical decontamination. Moreover, all investigated factors were existing variations of the routine processing practises and therefore proposed interventions are practically and economically achievable.

Effects of the Addition of Glucose, Sodium Bicarbonate, and Vitamin E to the Drinking Water of Pre-Slaughter Broiler Chickens on Carcass Yield, Gastric Emptying and Meat Quality

An experiment was conducted of the poultry facilities of La Salle Agricultural College in Xanxere, SC, Brazil, to evaluate the effect of the administration of sodium bicarbonate, glucose and vitamin E to the drinking water during pre-slaughter feed withdrawal on carcass yield, organ relative weights (heart, liver, proventriculus, and gizzard), gizzard emptying, and meat quality of broiler chickens. The applied treatments were: water as control; 50g/L of glucose; 50g/L de glucose + 200mg/L of vitamin E; 75g/L of glucose; 75g/L + 200mg/L of vitamin E; 0.45% of sodium bicarbonate; 0.45% of sodium bicarbonate + 200mg/L of vitamin E; 0.55% of sodium bicarbonate; 0.55% of sodium bicarbonate + 200mg/L of vitamin E; 200mg/L de vitamin E. On the last day before slaughter, during the water diet period,500 birds were distributed in a completely randomized experimental design with ten treatments and ten replicates of five birds each. No difference in broiler carcass yield and organ relative weights was found. There were no significant changes in gizzard contents, in ultimate meat, cooking loss, shear force value, or in the meat color parameters L* (lightness), a* (redness) and b* (yellowness). It was concluded is that the addition of glucose, sodium bicarbonate, and vitamin E to the drinking water during pre-slaughter feed withdrawal period has no influence on carcass yield or on relative organ weight, neither on the emptying of the gizzard contents and the meat quality of broiler chickens.