Body Weight Uniformity Research Articles

Effects of different feeding strategies on behavior and performance in broiler breeder pullets

This study examined the effects of different feeding strategies (diluted diets and feeding frequency) on the behavior and performance of broiler breeder pullets. A total of 3,200 1-day-old female pullets (Ross 308) were randomly distributed over 16 floor pens in 4 rooms and allocated to 1 of 4 treatments: (1) control diet once a day (CON), (2) 20% diluted diet once a day (20-ON), (3) 20% diluted diet twice a day (20-TW), and (4) 30% diluted diet twice a day (30-TW). All the pullets of the different treatments were fed to the same body weight (BW) profile. The 30-TW pullets had the highest and the CON pullets the lowest feed intake, with the 20-ON and 20-TW pullets showing intermediate values. Total water intake was the highest for the 30-TW pullets, followed by the 20-TW and 20-ON pullets, and was the lowest for the CON pullets (P < 0.001). The pullets fed twice a day had the highest total water-to-feed ratio, and the pullets fed once a day had the lowest ratio (P = 0.003). Feeding pullets twice a day yielded the highest average BW uniformity, while the pullets fed once a day had the lowest BW uniformity (P = 0.003). Total mortality was lower in the 20-TW and 30-TW pullets than in the 20-ON pullets, which was primarily caused by fewer dead and graded pullets. The pullets fed twice a day showed overall more eating, more drinking and less sitting, object pecking, and aggressive pecking. The behavior pattern during the daylight period was different for the pullets fed twice a day. Pullets on the diluted feeding strategies were less eager to approach the novel feeder and ate less feed (P = 0.002). In conclusion, feeding pullets with adjusted feeding strategies (feeding twice a day and up to 30% diluted diets) resulted in improved behavior and welfare expressed in decreased stereotypic pecking behavior, and lower eagerness to approach the novel feeder with lower feed intake, with improved BW uniformity and decreased mortality.

134 Does inclusion of high oleic soybeans in a swine finishing ration influence lipid oxidation and consumer taste panel preference?

Abstract The objective of this study was to determine if a swine finishing ration that included soybeans with greater concentration of oleic acid will have an impact on lipid oxidation and palatability of pork. Crossbred pigs [n = 72; initial body weight (BW) = 78 ± 9 kg] were blocked by BW, sex, and distributed within 18 pens. Each pen was randomly assigned to 1 of 3 experimental diets: a control soybean-meal (CTRL), extruded conventional soybean (CONV), and extruded high oleic acid soybean (TRU). Six different harvest groups (n = 12/group) were created across treatments to ensure uniformity of final BW. Therefore, experimental diets were offered to animals for 34, 37, 41, 42, 48, or 50 d, until all pigs reached 118 ± 5 kg. Carcasses were harvested, and chilled (2°C) for 24 h, before fabricating one 2.5 cm chop from the 11th rib of the right carcass side. The chops were vacuum packaged, aged for 7 d at 2 oC, and frozen (-18 oC) for later sensory analysis. Pork chops were thawed and cooked to 71 oC peak internal temperature (AMSA sensory guidelines) and fed to 115 consumers that rated overall liking, flavor, tenderness, juiciness, and presence of off flavors using hedonic scales. Also, a 50 g sample was obtained from each loin at the 12th rib, aged for 7 d and frozen at -80 oC for evaluation of malondialdehyde (MDA) as indicator of lipid oxidation. Subcutaneous fat samples were obtained from the first thoracic vertebra, frozen, and saved for fatty acid analysis. Data were analyzed using the MIXED procedure of SAS where diet was the main effect, while pen and breed were random effects. Repeated measures were used to analyze the consumer panel. Differences were considered significant at P ≤ 0.05 with pen as experimental unit. There were no significant differences (P &amp;gt; 0.05) for consumer perception of overall like, pork flavor, and presence of off flavors. Experimental diets impacted the perception of juiciness and tenderness (P &amp;lt; 0.05), where CONV was perceived as juicier and more tender than CTRL and TRU. As expected, diet affected the fatty acid profile of subcutaneous fat (P &amp;lt; 0.0001), with TRU having the greatest percentage for oleic (43.9 %), CONV the greatest percentage for linoleic and linolenic (17.8 and 1.3 % respectively), and CTRL for saturated fatty acids (34.5 %). Surprisingly, the lipid oxidation was not affected by the diet (P &amp;gt; 0.05). These results indicate that feeding extruded high oleic soybeans during the finishing period can modify the fatty acid profile in pork by improving the percentage of unsaturated fatty acids, so these soybeans can be considered as an alternative to improve nutritional value of pork without increasing the lipid oxidation or affecting the consumers acceptability.

Microenvironmental sensitivity of body weight at harvest in Nile tilapia: Genetic parameters, performance test traits, and genetic variability

Uniformity of body weight at harvest is a trait of great economic importance in Nile tilapia production. Studying the genetic aspects of microenvironment sensitivity proves to be a valuable instrument for enhancing the uniformity of production. The microenvironmental sensitivity of a given genotype can be quantified by analyzing the degree of genetic heterogeneity of environmental variance. This study involved the analysis of a database comprising phenotypic records of body weight at harvest for 10,207 individuals. It aimed to estimate genetic parameters, scrutinize the effects of direct selection, and evaluate how selection impacts the genetic variability within a Nile tilapia breeding program. Estimates of genetic parameters were obtained by Bayesian procedures using a two-step animal model in GIBBS1F90 (BLUPF90 family) software. The coefficients of variation for residual variance (0.29) and genetic correlation (−0.43) between body weight at harvest and microenvironmental sensitivity were deemed moderately favorable. Direct selection for microenvironmental sensitivity resulted in a 41% increase in the coancestry coefficient. The group chosen for low microenvironmental sensitivity exhibited a significant difference of 19.08% in the coefficient of variation from the group selected for high microenvironmental sensitivity. No significant differences in the coefficient of variation were observed between tilapia of the commercial line selected for growth rate and those selected for low microenvironmental sensitivity. Selection for microenvironmental sensitivity has the potential to enhance production uniformity. Significantly, directional breeding for performance achieves a comparable improvement in uniformity. Nevertheless, opting for direct selection for microenvironmental sensitivity could result in a decrease in genetic variability within Nile tilapia breeding programs.

Effect of herbal extracts as alternatives to antibiotics in the first week of age on broiler performance, serum biochemistry, and intestinal morphology under commercial farm conditions

This study was performed to show the effect of two herbal extracts as alternatives to antibiotics in the first eight days of rearing on broiler performance, serum biochemistry, and the jejunum morphology of the broiler. A total of 264, one-day Ross 308 chicks were used. They were randomly distributed into four treatments including three replicates of each. T1 was the control (nothing in drinking water), T2 had antibiotics in the drinking water (1 g/L of Gentadox), T3 had ENTERIA in the drinking water (0.5ml/L), T4 had ICEN in the drinking water (0.5ml/L). These products were administered for the first eight consecutive days of rearing. In the first seven days, there was no substantial variation in performance found in all groups. From days 8–14, T3 markedly improved body weight gain (BWG). The feed conversion ratio (FCR), thyroid hormones, total protein, and globulin were substantially improved in T3 and T4. The edible internal organs and heart percentage was substantially increased in the herbal groups. All the jejunum histology parameters, except the crypt depth, were substantially increased in T3. The T3 recorded the best bodyweight uniformity and economic efficiency compared to other groups. Similarly, the yolk sac residual at days 4 and 7 was lower in this group compared to other groups. It can be concluded that herbal extracts can replace antibiotics in improving and enhancing general broiler performance.

Comparative efficacy of hydroxychloride and organic sources of zinc, copper, and manganese on egg production and concentration of trace minerals in eggs, plasma, and excreta in female broiler breeders from 42 to 63 weeks of age

Comparative efficacy of hydroxychloride (HC) and organic (OR) sources of Zn, Cu and Mn on performance of broiler breeders (BB) between 42 and 63 weeks of age (WOA) was investigated. A total of 408 ♀ Ross 708 and 48 ♂ Yield Plus cockerels were placed in pens (17 ♀ and 2 ♂) housed in 2 rooms (12 pens/room) and allocated to one of 2 diets in a completely randomized block design (n=12). The diets had similar nutrient specifications but differed in Zn, Cu, and Mn sources: 1) HO, a blend of 80% HC and 20% OR sources, and 2) OR, 100% OR sources. Birds were fed and managed according to breeder guidelines. The egg count was recorded daily and categorized as normal or abnormal. Egg yolk color, albumen height, Haugh unit, eggshell thickness, and eggshell breaking strength were assessed every 4 wk. Individual hen body weight (BW) was recorded at 5-wk intervals to determine BW uniformity. At 52 and 63 WOA, the eggs and excreta samples were collected. At the end of the trial, 4 hens per pen were bled for plasma concentration of trace minerals and organs (liver, gizzard, spleen, kidney, and thymus) weight. There were no interactions between source and age on any parameters (P > 0.05). There were no main effects of source on egg production, eggshell quality, BW, and organs weight (P > 0.05). Hens fed HO diets had darker yolk compared to those fed OR diets (P = 0.014). The concentration of Zn in the eggs of OR BB was higher (P = 0.022) than for HO birds. However, there were no dietary effects on the concentration of trace minerals in the egg, plasma, and excreta (P > 0.05). The results indicated that a mixture of HC and O as sources for Zn, Cu, and Mn was as effective as OR sources in supporting egg production, egg quality, and trace mineral utilization in broiler breeders.

Effects of grain-based pecking blocks on productivity and welfare indicators in commercial broiler chickens.

This experiment was conducted to investigate the effect of grain-based pecking blocks on productivity and welfare status at two commercial broiler welfare-certified farms. Production and welfare indicators were assessed at two farms (designated Farm A and B). Both farms had two windowless houses with forced tunnel-type ventilation and housed broilers at stocking densities of approximately 16.7 birds/m2 (Farm A) and 16.8 birds/m2 (Farm B). Each house was divided into two or three equal sections and was provided with or without pecking blocks. Grain-based pecking blocks, measuring 25 × 25 × 25 cm, were given to broilers in both farms at 1 block per 1,000 birds. Various parameters including productivity (body weight and flock uniformity), corticosterone levels (in fecal droppings and feathers), footpad dermatitis, hock burn, feather dirtiness, gait score, litter quality, body surface temperature, and volatile fatty acids in fecal samples were assessed at 26 days of age, whereas litter quality was analyzed at 13 and 26 days of age. There were no significant effects of providing pecking blocks on productivity (body weight and uniformity), fecal and feather corticosterone, welfare indicators (i.e., footpad dermatitis, hock burn, feather cleanliness, and gait score), and litter quality (i.e., moisture, nitrogen, and pH). No differences in body surface temperature between the control and enrichment treatments were noted in Farm B, but body surface temperatures of the head (p = 0.029) and legs (p = 0.011) in the enrichment vs. control group were elevated in Farm A. Butyrate concentration in the enrichment vs control group was higher in Farm B (p = 0.023), but this effect was not detected in Farm A. It is concluded that grain-based pecking blocks did not affect performance and welfare indicators. Further studies are warranted to elucidate the potential impact of grain-based pecking blocks on gut health indicators.

Response of broiler breeder pullets when fed hydrolyzed whole yeast from placement to 22 wk of age

The study examined the effects of feeding broiler breeder pullets hydrolyzed whole yeast (HY) from hatch to 22 wk of age (WOA). A total of 524-day-old Ross 708 pullets were placed in floor pens (∼24 birds/pen) for the starter (0-4 WOA) and grower (5-18 WOA) phases, then transferred to the egg production facility and redistributed to ∼20 birds/pen for the prelay phase (19-22 WOA). Two diets were allocated to pens (0-18 WOA; n = 11) and (19-22 WOA; n-12). The diets were a control corn and soybean meal diet formulated to meet specifications and control plus 0.05% HY (HY). Birds had ad libitum access to feed in the first week and daily feed allocation based on pen BW from 2 WOA. Birds had free access to water throughout the trial. Body weight (BW) and uniformity (BW CV) were monitored. Boosters for infectious bronchitis and New Castle disease vaccines were administered at 18 WOA, and samples of pullets bled for antibody titer 5-day later. One pullet/pen was randomly selected, weighed, bled for plasma biochemistry, and necropsied for organ weights, ceca digesta for short-chain fatty acids (SCFA), and leg bones morphometry. In the starter and grower phases, birds fed HY were lighter and gained less (P < 0.05) than control birds. However, there were no diet effects (P > 0.05) on growth, the BW prelay phase, or BW uniformity throughout the trial. There were no (P > 0.05) diet effects on breast, gastrointestinal, liver and bursa weights, serum antibody titers, plasma biochemistry, SCFA and bone attributes. However, pullets fed HY had heavier (P = 0.047) spleen and tended to have lower (P = 0.080) plasma concentrations of aspartate aminotransferase (AST) relative to control pullets. In conclusion, the parameters assessed showed no negative consequences of feeding HY to broiler breeder pullets. However, effects on the spleen and plasma AST may indicate modest modulation of immunity and metabolism. The impact of the provision of HY during broiler breeder pullet phase on reproductive performance and chick quality should be investigated.

308 Effect of Thermal Variation During Late-Stage Incubation and Sex on Broiler Chicken Body Weight and Carcass Parts Uniformity

Abstract Low uniformity of broiler live body weight, carcass, and parts weights can reduce overall processing yields and profitability. The objective of this study was to evaluate the effects of thermal manipulation (TM) during late-stage incubation (LSI) and sex on the uniformity and coefficient of variation (CV) in high yielding broilers. Yield Plus ′ Ross 708 broiler breeder eggs (n = 2,160) were incubated at 37.5 °C from embryonic day (ED) 0 to 10. From ED 11 to 18, eggs were incubated at 1 of 3 air temperature set points: 37.5 °C (CTL), 36.4 °C (COLD), or 38.6 °C (HOT; n = 2 incubators per treatment). On ED 18, all eggs were transferred to baskets in hatchers set to 36.7 °C. Chicks were vent sexed, placed in floor pens blocked by incubation treatment and sex (n = 6 replicate pens of 30 birds per treatment), and fed a common diet. Broilers were individually weighed at d 9, 23, and 32, then, the 15 birds from each pen closest to the pen median BW were processed on d 33. The distance of each bird BW from the pen mean and median, TM treatment, sex, and whole flock BW over time, uniformity of BW (within 10% of the mean), and intra-pen CV were calculated. Data were analyzed as a 2-way ANOVA using the GLIMMIX procedure of SAS ver. 9.4 with TM treatment and broiler sex serving as the main effects. Means were separated at P ≤ 0.05 with the PDIFF option. On d 9, a TM by sex interaction was observed, and the BW of female CTL chicks was less variable from the pen mean compared with broilers hatched from COLD and females from HOT incubators (P ≤ 0.026). On d 9, sub-optimal incubation temperatures (HOT and COLD) during LSI resulted in higher individual female bird BW variation from the pen mean and median (P = 0.013). Incubating chicks in COLD incubators during LSI increased d-9 individual bird BW distance from the treatment, sex, and flock mean and median BW compared with CTL and HOT (P ≤ 0.037). In addition, BW uniformity within a pen was less in broilers hatched from COLD incubators than both CTL and HOT on d 9 (P = 0.033) and tended to be less on d 32 (P = 0.099). The inverse was observed for CV (P ≤ 0.040). Broilers hatched from COLD and HOT incubators had greater CV for carcass (P = 0.049) and wing (P = 0.028) as well as drumstick (P = 0.079) weights. These results indicate that sub-optimal LSI conditions can negatively influence uniformity of broiler live BW, carcass and parts weights and highlights the importance of achieving optimal incubation conditions.

Effect of beak trimming at hatch and oat hulls inclusion in the diet on growth performance, preference behaviour for coarse particles and gastrointestinal tract traits of brown-egg pullets from 1–35 days of age

The effects of infra-red beak treatment (IRBT) at hatch and the inclusion of oat hulls (OH) in the diet on growth performance, water intake (WI), preference behaviour for coarse particles and the development of the gastrointestinal tract (GIT), was studied in brown-egg pullets from 1 to 35 days of age. The experimental design was completely randomized with 4 treatments arranged as a 2 × 2 factorial with beak treatment (IRBT vs. sham) and OH inclusion (0 vs. 30 g/kg diet) as main effects. Each treatment was replicated 20 times and the experimental unit was a cage with 10 pullets. Growth performance and water intake were determined by week and cumulatively. Preference behaviour for coarse particles and the development of selected organs of the GIT, were determined at 28 and 35 days of age, respectively. No interactions between IRBT and OH inclusion were detected for any of the traits studied at any age, and therefore, only main effects are discussed. Cumulatively (1–35 days of age), IRBT increased mortality (P<0.01) and reduced feed consumption (P<0.001), body weight (BW) gain (P < 0.01) and water intake (P < 0.001), but improved feed conversion (P < 0.001) of the pullets. Oat hulls inclusion did not affect BW gain, BW uniformity or energy conversion ratio, but reduced pullet mortality (P = 0.099) and water to feed ratio (P < 0.05). The interactions detected between age and IRBT on pullet performance were numerous. From 1–21 days of age, BW gain was better for the sham than for the IRBT pullets but an opposite effect was observed from 29 to 35 days of age (P < 0.01). Similarly, from 1 to 28 days of age, BW uniformity and WI were higher for the sham than for the IRBT pullets but no differences were detected from 29 to 35 days of age. Preference behaviour for coarse particles, measured at 28 days of age, was greater for the sham than for the IRBT pullets (P < 0.001). In summary, infra-red beak treatment increased mortality from 1 to 7 days of age and reduced pullet performance from 1 to 28 days of age but not thereafter. Young pullets show a clear preference to consume coarse particles. Oat hulls inclusion increased feed intake and decreased mortality and water to feed ratio of the pullets but did not affect energy efficiency or the development of the gastrointestinal tract.

The impact of marker selection, in-line near-infrared spectroscopy (NIR), and feed mix time on the coefficient of variation (mix uniformity), body weight uniformity and broiler growth performance during the starter, grower, and finisher periods

Most feed manufacturers in the United States use the same mixing time (and thus mix uniformity) throughout the growing period regardless of age and consumption patterns. However, research evaluating the optimum mixing time requirements and novel analysis methods, such as in-line near-infrared (NIR) spectroscopy, on the coefficient of variation (CV) and growth performance of broilers throughout the production phases is sparse. Two experiments were conducted to determine the effects of marker selection, in-line NIR, and varying mix times on mix uniformity, broiler growth performance, and body weight uniformity from 1 to 42 d of age. Feed was manufactured utilizing a 1,815-kg counterpoise ribbon mixer. In both experiments, feed was mixed for 4.5 min (3 min dry mix and 90 s of wet mix) and 30 s (0 s dry mix and 30 s wet mix) to obtain a standard mix (SM) and an abbreviated mix (AM), respectively. Experiment 1 constituted a 2×2×4 factorial arrangement of 2 mix times, (4.5 and 0.5 min), 2 batch sizes (908 and 1,815 kg), and 4 methodologies to evaluate mixer performance (sodium chloride, Microtracers (Red#40 and Blue#40), and in-line NIR). In experiment 2, broilers received different mix time combinations: 1) SM from 1 to 42 d, 2) SM from 1 to 28 d and AM from 28 to 42 d, 3) SM from 1 to 14 d and AM from 14 to 42 d, and 4) AM from 1 to 42 d. In both experiments, selecting a single source marker provided a more accurate estimation of mixer CV in SM and AM diets (P < 0.05). In experiment 2, mix time did not influence BW, feed intake (FI), FCR, or individual bird BW CV from 1 to 42 d of age (P > 0.05). These data indicated that mixer CV differed depending on total mix time and methodology used and diets with a reduced mix time may not necessarily influence growth performance and BW uniformity during the starter, grower, and finisher periods of broilers.

Development and evaluation of an animal health and welfare monitoring system for veterinary supervision of pullet farms.

Regular welfare monitoring throughout rearing of pullets may help to identify problems early and take counteractions timely, which helps in guaranteeing good welfare. The aims of our observational study were (i) to establish and test a welfare monitoring system that can be used during (short) routine veterinary and technical staff visits for pullet flocks, (ii) to use the monitoring system to investigate variability between flocks and (iii) to analyse factors that potentially affect pullets' body weight, uniformity in body weight and mortality. The developed monitoring system tries to minimise the time required while not losing important information. Age-specific recording sheets comprise animal-based indicators of welfare and relevant environmental factors (housing, management, care) to allow for identifying causes of problems and targeted action. Finally, the system was implemented in a cross-sectional study and data collected in 100 flocks (67 organic, 33 conventional) on 28 rearing farms in Austria. Linear mixed models were used to identify factors influencing body weight, uniformity and mortality, both including all flocks (A) and only organic flocks (O) and a linear regression model with all flocks to investigate associations within animal-based indicators. High variability was found between flocks in animal-based indicators. Body weight was higher when the pre-rearing period was shorter (p≤0.001, A&O), with higher intensities of light (p=0.012, O), with only one compared to more stockpersons (p≤0.007, A&O), with a higher number of flock visits per day (p≤0.018, A&O), and a lower avoidance distance (p=0.034, A). Body weight uniformity increased, with age and decreased with the duration of the light period (p=0.046, A), and, amongst others, was higher on organic farms (farming type; p=0.041). The latter may reflect a more uniform level of welfare due to a lower stocking density and lowered effects of social competition. Within organic flocks mortality was lower if pullets had access to a covered veranda (p=0.025) resulting in an overall lower stocking density inside the barn, while in the model including all farms mortality was higher in cases where a disease had been diagnosed. We conclude that our monitoring system can easily be implemented in regular veterinary and technical staff visits, but could also be used by the farmers'. Several easy-to-record animal-based indicators of animal welfare could be analysed more frequently to increase early detection of problems. Implementation of such a routine-based monitoring system with easy-to-assess animal-based parameters and input measures can contribute to better animal health and welfare in pullets.

Effects of energy restriction during growing phase on the productive performance of Hyline Brown laying hens aged 6 to 72 wk

The aim of this study was to assess the effects of energy-restricted feeding during growing phase on the productive performance of Hyline Brown laying hens aged 6 to 72 wk. A total of 720 six-week-old layer chicks were allocated equally to 3 groups with 6 replicates of 40 pullets each, and were fed 1 of 3 diets that were nutritionally similar except for the apparent metabolizable energy corrected for nitrogen (AMEn) content. At the age of 6 to 17 wk, the pullets in the control group were given diet with 2,850 kcal/kg AMEn, and were fed ad libitum. The levels of AMEn in diet of pullets in the experimental groups were 90% (2,565 [2,850×90%] kcal/kg) and 80% (2,280 [2,850×80%] kcal/kg) of that in control group, and the daily amount of feed was restricted to the absolute quantity of the diet consumed by pullets in control group. At the age of 18 to 72 wk, all the hens were fed with the same diets ad libitum. As energy restriction increased in the growing phase, body weight (BW) dropped at the ages of 12 and 15 to 23 wk (at 23 wk: P=0.001; at other ages: P < 0.001), but it showed no significant difference at 24 wk (P=0.071). At 20 wk, restricting energy induced a delay in the development of sexual organs, including the ovary stroma, oviduct, and small yellow follicle (P < 0.05), as well as a delay in sexual maturity (P < 0.05). Consequently, the laying rate in the first and second periods dropped linearly (P=0.046, 0.030, and 0.038, P < 0.001, respectively). The coefficient of variation (CV) in the BW at 19, 20, and 21 wk (P=0.040, 0.023, and 0.042, respectively), the CV of age at first egg (P < 0.001), and CV of individual egg number at age 18 to 72 wk (P < 0.001) decreased linearly. There was a linear increase in the laying rate of hens in the later periods (at age 32-72 wk, P < 0.05), as well as in the average total egg number per hen and average laying rate at the age of 18 to 72 wk (P=0.006). The average egg mass also showed a linear increase with increasing levels of energy restriction (P < 0.001). In summary, although appropriate energy restriction during growing phase delayed sexual maturity and sexual organ development in early-laying Hyline Brown pullets, it improved uniformity of BW, age at first egg laying, and individual egg number, and increased egg number per hen, laying rate, average egg mass, and number of settable eggs from 18 to 72 wk of age.

Effect of feed form and nutrient density on growth performance, blood parameters, and intestinal traits in broiler breeder pullets

This study was conducted to evaluate the effect of feed form and nutrient density on growth performance, blood parameters, and intestinal traits of broiler breeder pullets during grower (7-19 wk) and pre-breeder (19 weeks to 5% production) periods. A total of 450 female broiler breeder pullets were used in a completely randomized design with a 3×2 factorial arrangement including 3 feed forms (mash, crumble, and pellet) and 2 nutrient densities (standard diet with the nutrient requirement of Ross 308 parent stock nutrition specification, and diluted diet by using sunflower hull to have 10% lower nutrient than the standard diet). Five replicates with 15 pullets per replicate were allocated to each of the 6 treatments. Blood samples were collected at 19 wk of age. Egg production reached 5% in the mid of 25 wk. Results showed that pullets fed crumble or pellet diets had greater body weight gain and a lower feed to gain ratio (F:G; P < 0.001). Diet dilution led to a decrease in body weight gain while increasing the F:G (P < 0.05). Pullets fed the pellet diets had shorter eating times than those fed crumble diets, whereas the longest eating time belonged to pullets fed mash diets (P < 0.001). Pullets fed pellet diet had a greater heterophil to lymphocyte (H/L) ratio than those fed crumble or mash diets (P=0.007). Diluting the diet led to a decrease in the H/L ratio (P=0.026). Neither feed form nor nutrient density had a significant effect on body weight uniformity, blood glucose and lipid concentrations, liver enzyme activities, and intestinal traits (P > 0.05). It can be concluded that pelleted or crumbled diets with lower nutrient density can be considered in broiler breeder's pullets feeding with no detrimental effect on their performance or health state.

Evaluasi Kebutuhan Nutrien dan Suplementasi Zinc untuk Calon Galur Ayam IPB-D2 Fase Pre-layer

This study aimed to evaluate nutrient requirements and zinc supplementation for IPB D-2 pre-layer chicken line candidates on performance, blood profile, and blood malondialdehyde (MDA). This study used 200 of 16 weeks IPB-D2 chickens line candidates reared until 19 weeks of age (pre-layer phase). This study used a completely randomized design (CRD) with 2 treatments and 10 replications. The treatment rations were formulated to fill the chicken nutrient requirements according to Lohman (2020) without the addition of Zinc and with the addition of 120 ppm Zinc. The data were analyzed using the T test. The results showed that the ration supplemented with 120 ppm zinc did not significantly affect performance, but it was able to increase body weight uniformity. The 120-ppm Zinc supplementation significantly (p&lt;0.05) decreased erythrocytes, however it tended to lower blood MDA. In conclusion, 120 ppm Zinc supplementation in the ration is sufficient to meet the nutrient requirement of IPB-D2 chicken line candidates in the pre-layer phase.&#x0D; Key words: IPB-D2 chicken line candidates, Zinc, performance, blood profile, MDA

Rearing broilers as mixed or single-sex: relevance to performance, coefficient of variation, and flock uniformity

With known variation in performance between male and female broilers and the fact that sourcing single-sex birds for use in research is becoming increasingly difficult, it becomes important to determine the effect of rearing method with male and female broilers on between-pen variation and body weight (BW) uniformity. We evaluated the performance response of broilers reared as single or mixed-sex to standard and reduced crude protein (CP) diets. The study was designed as a 2 × 3 factorial arrangement of treatments consisting of 672 Cobb-500 broilers assigned to 48 floor pens with 6 treatments, 8 replicates, and 14 birds per pen. The factors were rearing method (male single-sex, female single-sex, or equally mixed-sex) and dietary CP level (standard or reduced). For the overall period of the trial (d 0–35) there was a significant effect (P < 0.001) of rearing method and CP level on feed intake (FI) and feed conversion ratio (FCR). There was also a significant interaction between rearing method and CP level for BWG during d 0 to 35 (P < 0.01). There was a significant interaction between CP level and sex on d 34 BW (P < 0.01) where the reduced CP diet decreased the BW of both males and females, but to a greater extent the BW of the female birds. Dietary CP level had a significant effect on relative breast and drumstick weights with birds fed the reduced CP diet having significantly lower breast weights (P < 0.001) and higher drumstick weights (P < 0.01).This study suggests that male and female broilers have different CP requirements, and rearing birds as equally mixed-sex results in the lowest CV% for performance parameters and best BW uniformity compared to single-sex birds. Furthermore, when low CP diets are fed to broilers, they will prioritize the growth of more important body parts such as the legs.

Growth performance of broiler chickens fed on feeds with varying mixing homogeneity

In feed manufacturing, the need for an effective combination of ingredients to produce a complete feed for animals is well known. However, limited quantitative data illustrate the effect of low homogeneity on the performance of animals. This study was conducted to determine the coefficient of variation (CV) of feed mixtures produced with different mixing times and the effects of these feeds with varying homogeneity consumed by 1–40-day-old broilers on their feed intake, body weight gain, feed conversion, mortality, and body weight uniformity. The mixing times used were 30, 60, 90, and 120 s, and the CV obtained from the feeds ranged from 49.5% to 5.4%. A linear decrease was observed in the feed CV with increasing mixing time, but sometimes, a longer mixing time did not present the lowest CV. The influence of the lack of feed homogeneity on the performance of broilers was mainly observed in body weight gain and, in some cases, in feed conversion. The effects on feed intake were more consistent for broilers older than 22 days, increasing body weight gain without affecting feed conversion. Our results suggest that feeds with CVs up to 22.6% had no adverse effects on the performance of broilers older than 12 days, and the lack of uniformity in broiler body weight was not influenced by feed homogeneity.

Quality Assessment of Day-Old Chickens on the Broiler Farms of Hong Kong.

Simple SummaryAssessing the quality and determining maternal antibodies against regional pathogens in day-old chickens is important to optimize the production performance and management of flocks. So far, such information in Hong Kong is lacking. The present study was conducted to assess abnormalities in appearance, navel, crop filling, dehydration, body weight, and length uniformity in day-old chicks. In addition, the maternally derived antibody levels against relevant infectious diseases were measured. This study was the first in Hong Kong to provide a baseline for the quality of day-old chicks, and results in evidence-based management advice tailored to the farms. We advise the establishment of a well-managed broiler breeder farm and hatchery, in order to improve the health and productivity of the local broiler chicken industry.The present study aimed to investigate the quality of newly hatched broiler chicks delivered to Hong Kong (imported or local), and to develop tailored recommendations to improve their management. During 2019–2021, 70 batches (34 imported from mainland China and 36 local) of one/three day old chicks on 11 broiler farms were studied. From each batch, 23 or 24 chicks (1647 in total) were assessed for abnormalities in appearance, navel, crop filling, dehydration, body weight, and length uniformity. Chicks were sacrificed, and yolk sac residues in three day old chicks were measured. Maternally derived antibody levels against Newcastle disease virus (NDV), infectious bursal disease virus (IBDV), and avian reovirus (ARV) were measured in all chicks using an enzyme-linked immunosorbent assay (ELISA). The proportion of abnormal navel in most batches is high (median: 59%), ranging between 0 and 100%. The average length of chicks within batches ranges between 16.3 and 20.7 cm, and their average weights are 31–38.5 g upon delivery to the farms. On average, imported batches have a higher body weight and length than their local counterparts. The average yolk-free weight varies between 45 and 55 g, which is significantly lower in local batches (33–43 g). The mean antibody titers against NDV and ARV are higher in imported batches than in the local ones. In contrast, the mean antibody titer against IBDV is significantly lower in the imported batches. Concerning the overall lower quality of local chicks compared to the imported batches, establishing a well-managed broiler breeder farm and a hatchery in Hong Kong is highly recommended to enhance the health and productivity of the local broiler chicken industry.

Impact of every-day versus skip-a-day feeding of broiler breeder pullets during rearing on body weight uniformity and reproductive performance

Genetic selection for increased growth rate in broilers makes feed restriction programs such as skip-a-day (SAD) feeding, for broiler breeders essential to managing body weight, flock uniformity, and reproductive performance. The objective of this experiment was to compare intestinal development, weight gain of breeder pullets, and reproductive performance (22–45 wk) when fed a high fiber diet (3.8% crude fiber) on either an every-day (ED) or SAD basis during rearing. The same developer ration and feed amounts were fed to both treatments. Day-old Ross 708 pullet chicks (n = 912) were randomly distributed into 4 floor pens (n = 228/pen, 2 pens/treatment). At 20 wk of age all birds were weighed, and the coefficient of variation (CV) and average body weight was calculated for each treatment. Birds were then distributed into 10 lay pens (n = 35 birds/pen, 5 pens/treatment) at 21.5 wk of age. Light was increased from 8 h to 15.25 h at move to the lay facility, and all birds were daily fed for the remainder of the study. Data were analyzed by SAS SLICE using a significance level of P ≤ 0.05. During lay, 25% of the birds from each treatment were weighed weekly to adjust feed and monitor body weight. At 21 wk the ED fed pullets were more uniform (P = 0.0007) than the SAD fed pullets. Eggs were collected daily and set for hatch every 4 wk from 28 to 42 wk of age. No significant difference in the hatch data were observed. The ED fed birds achieved first egg at 166 d of age while the SAD fed birds achieved first egg at 173 d of age. Specific gravity was measured every 2 wk from 30 to 40 wk, with ED reared birds having better overall eggshell quality (P = 0.02) and greater egg weight (P < 0.0001) than those fed SAD. Feeding a high fiber diet on an ED basis during rearing, improved body weight uniformity in rearing, encouraged early lay, improved eggshell quality and increased egg weight.

Perfomnce, Intestine Morphology And Serum Biochemistry of Broiler Chickens to Delayed Post Hatch Feeding

This study was conducted to estimate the effect of delayed post hatch feeding after arrival to the rearing hall on broiler performance, serum biochemistry and jejunum histology.&nbsp; A total of 225 Ross 308 day-old chicks were randomly distributed into three groups T1 chicks access to feed immediately, T2 chicks delayed in feeding for 12 hours and T3 chicks delayed in feeding for 24 hours with three replicates of 25 chicks. Remained yolk sack was lower for chicks that had immediate access to feed compared to other experimental groups. Longer delay feeding time lowered body weight uniformity % at different ages. Immediate access to feed significantly (P&lt;0.05) improved broiler performance at different ages compared to that delayed for 12 and 24 hours post hatch. Significantly (P&lt;0.05) longer small intestine and higher percent of live body weight were recorded for early feeding groups compared to delayed groups. The level of T3 and T4 hormones in the serum were significantly (P&lt;0.01) higher for early feeding groups compared to other groups. Increasing delayed post hatch feeding led to a significant (P&lt;0.01) increase in uric acid level in serum. Early feeding significantly (P&lt;0.01) improved jejunum histology including villi height, villi width, villi height to crypt depth and surface area

Body weight, organ development and jejunal histomorphology in broiler breeder pullets fed n-3 fatty acids enriched diets from hatch through to 22 weeks of age

Dietary long chain polyunsaturated n-3 fatty acids (n-3 FA) may be beneficial to broiler breeder (BB) development. Therefore, the effects of feeding sources of docosahexaenoic acid (DHA) and α-linolenic acid (ALA) from hatch through to 22 weeks of age (woa) on growth, organ weight, and jejunal histomorphology were investigated. A total of 588-day-old Ross × Ross 708 BB were reared on one of 3 diets: 1) control, corn-soybean meal diet, 2) Control + 1% microalgae (DMA, Aurantichytrium limacinum), as a source of DHA and 3) Control + 2.50% co-extruded full fat flaxseed and pulse mixture (FFF, 1:1 wt/wt), as a source of ALA. Diets DMA and FFF had similar total n-3 and n-6: n-3 ratio. Diets were allocated to floor pens (28 birds/pen) to give 9 or 6 replicates per diet for control or DMA and FFF, respectively and fed according to breeder curve in 3 phases: starter (0–4 woa), grower (5–19 woa), and pre-breeder (20–22 woa). Individual body weight (BW) was taken weekly and 6 birds/pen necropsied at 5 and 12 woa for gastrointestinal, spleen, bursa, and liver weight and samples for jejunal histomorphology. There was no (P > 0.05) diet effect on growth by 20 woa. With exception of 5 woa, pullets fed DMA showed (P < 0.001) lower BW coefficient of variation (C.V.) than pullets fed control between 2 and 7 woa. However, pullets fed DMA had higher BW CV at 20 woa than birds fed either control or FFF. At 5 woa, birds fed DMA had taller (P ≤ 0.01) villi and deeper crypt than birds fed either control or FFF but VH or CD were similar (P > 0.05) between CON and FFF pullets. At 12 woa, birds fed FFF had taller VH than birds fed control diet but similar (P > 0.05) to that of birds fed DMA. Therefore, different responses to sources of omega-3 FA may implicate other components, however, the BW uniformity and intestinal histomorphology responses suggested benefits of feeding omega-3 FA during rearing.