Pen Basis Research Articles

The impact of β-glucans on performance and response of broiler chickens during a coccidiosis challenge.

Coccidiosis is a costly parasitic disease to the poultry industry with multiple prevention methods being explored to control its impact. This study evaluated the feeding effects of β-glucans on performance and responses of chickens during a coccidiosis challenge. Cobb 500 male broilers (n = 1280) were assigned to 1 of 8 treatment groups (8 replicate pens; 20 birds/pen) in a 2 × 4 factorial arrangement, including non-infected and Eimeria-infected birds fed for 28 d a control diet, control + BG (150g/MT Algamune 50), control + BGZn (100g/MT Algamune 50Zn), and control + 0.01% Salinomycin (Sal). On d15, birds in the challenge groups received a mixed Eimeria inoculum. Birds and feed were weighed weekly on a per pen basis to evaluate body weight gain (BWG), feed intake (FI), and feed conversion ratios (FCR). Lesion scores were assessed 6 d post infection (d21) on 3 birds per pen. Performance data were subjected to ANOVA and differences were established using the LS-MEANS statement with significance reported at P ≤ 0.05. There were minor differences in lesion scores among the dietary treatments in the infected groups with reduced duodenal and cecal scores in the Sal group compared to the BGZn and BG groups, respectively. The coccidiosis challenge main effect resulted in a significant reduction in 0-28 d BW and FI. Dietary treatment resulted in non-significant effect on BWG, but Sal addition resulted in increased FI. A significant diet X challenge interaction resulted in higher FCR in the Eimeria-challenged birds supplemented with Sal and BGZn in comparison to the other challenged groups, likely due to reduced mortality in the challenged Sal and BGZn groups. Body composition analysis at d28 revealed that the Eimeria challenge reduced both fat and lean tissue contents, where the β-glucans and Sal birds had lower fat percent than control birds.

Performance and welfare of steers housed on concrete slatted floors at fixed and dynamic (allometric based) space allowances.

The objectives of the study were to determine whether allometric equations are suitable for estimating the space requirements of finishing beef cattle housed on concrete slatted floors (CSF) and to examine the effect of fixed and dynamic space allowances on the performance and welfare of these cattle. Continental crossbred steers [n = 120: mean initial live weight, 590 (SD 29.8) kg] were blocked by breed, weight, and age and assigned to 1 of 5 space allowance treatments (3 fixed and 2 dynamic) on CSF: 1) 2.0 m2 per animal, 2) 2.5 m2 per animal, 3) 3.0 m2 per animal, 4) Equation 1 (E1); y = 0.033w0.667, where y = m2 per animal and w = body weight, and 5) Equation 2 (E2); y = 0.048w0.667. The length of the feed face was 3.0 m for all treatments. Steers were offered grass silage and concentrates ad libitum. DMI was recorded weekly on a pen basis. Steers were weighed and dirt scored every 14 d. Blood samples were collected every 28 d, and analyzed for complete cell counts. Behavior was recorded using closed-circuit infrared cameras. Steers' hooves were inspected for lesions at the beginning of the study and post-slaughter. Slaughter weight and ADG were lowest, and feed conversion ratio (FCR) was poorest, for steers accommodated at 2.0 m2, and slaughter weight and ADG were greatest, and FCR was the best, for steers accommodated at E2 (P < 0.05); steers accommodated at 2.5 m2 were intermediate (P > 0.05) to those accommodated at 2.0 m2 and both 3.0 m2 and E1, whereas steers accommodated at 3.0 m2 and E1 were intermediate (P > 0.05) to 2.5 m2 and E2. Carcass weight of steers housed at 2.0 m2 was lower (P < 0.05) than all other treatments. Steers housed at 2.5 m2 had lower carcass weights (P < 0.05) than those with accommodated at E1 and E2, whereas the carcass weight of steers accommodated at 3.0 m2 was intermediate. Carcass fat scores and hide weights were lower (P < 0.05) in steers accommodated at 2.0 m2 than those housed at E2 with other treatments being intermediate. The number of steers lying at any one time and the number of steers observed grooming themselves was lower (P < 0.05) at 2.0 m2 than any other treatment. Dirt scores, hoof lesion number, and hematological measurements were not affected by treatment. It was concluded that 2.0 m2 per animal was an insufficient space allowance for housing finishing beef steers and that the equation y = 0.033w0.667 is sufficient for estimating the space required by finishing beef cattle housed on CSF.

Whole sorghum inclusion and feed form on performance and nutrient digestibility of broiler chickens

SummaryA total of 432, one-day-old broiler chickens were randomly assigned as a 2 × 4 factorial design (pellet or mash and 0, 25, 50, and 75% whole sorghum levels) in a completely randomised experiment, having six replicates with nine birds per replicate. Body weight and feed intake were measured on a pen basis at 10, 25, and 35 days of age and feed conversion ratio calculated. Pelleting diets significantly improved (P&lt;0.05) feed intake, body weight and carcass yield of broiler chickens at 10 and 24 days of age. Heavier relative gizzard weights with lower pH (P&lt;0.05) were recorded for broiler chickens offered mash diets at 35 days old. Feed conversion ratio at 35 days of age increased (P&lt;0.035, quadratic effect) with higher levels of whole sorghum and levelled off at 75% inclusion rates. Relative gizzard weight at 35 days was marginally increased (P&lt;0.033, linear effect) in line with rising sorghum levels. Similarly, relative bursa and liver weights at 35 days increased (P&lt;0.037, quadratic effect and P&lt;0.033, linear effect, respectively) with sorghum inclusion. The results showed that pelleted diets gave superior performance compared to mash diets. Although higher levels of sorghum inclusion in mash diets enhanced gizzard development, performance parameters of birds at 35 days of age were poorer, with 125 g less body weight and an increase in FCR from 1.51 to 1.62 for the 0% and 75% sorghum levels respectively.

Effect of Dietary Incorporation of Azolla Meal on Production Performance and Egg Quality of Vanaraja Laying Hens

An experiment was conducted to evaluate the effect of dietary incorporation of Azolla meal on production performance and egg quality of Vanaraja laying hens. Seventy two, 48-weeks old Vanaraja laying hens were randomly distributed into three dietary treatment groups of 24 hens each and were reared in deep litter system. Each treatment contained 4 replicates of 6 hens each. Three experimental diets were formulated by incorporating Azolla meal (AZM) at 0, 5% and 10% levels. A measured quantity of feed (150 g/day) was offered to each bird everyday during the experimental period. Egg production was recorded daily on individual pen basis and percent hen housed egg production (HHEP) was calculated. The average feed consumption was recorded as g/hen/day and feed efficiency was calculated on the basis of feed consumed per unit egg mass production. All the eggs laid during the last five consecutive days of each 28 days period were collected to measure the egg weight. Twelve eggs were randomly chosen in each treatment from the eggs laid during the last three consecutive days of each 28-day period to determine the egg quality. Dietary incorporation of AZM at either 5 or 10% level reduced the body weight of laying hens. The egg production, egg weight, egg mass per day and feed conversion efficiency (g feed/g egg) was comparable among the 0% (control), 5% and 10% AZM incorporated diets. The egg quality indices like albumen, yolk and egg shell percentage observed were similar across the different dietary treatment groups. Similarly, Dietary incorporation of AZM upto 10% in the diet had no influence on Haugh unit and shell thickness.

Effect of meloxicam administration on movement, feeding, and drinking behaviors of transported and nontransported cattle.

OBJECTIVE To evaluate the effects of meloxicam on movement, feeding, and drinking behaviors of transported and nontransported cattle. ANIMALS 100 crossbred beef steers. PROCEDURES During experiment 1 of a 2-experiment study, calves from a livestock auction received meloxicam (1 mg/kg, PO; n = 50) or a lactose placebo (1 capsule/calf; 50; control), then calves were transported approximately 1,000 km overnight to a feedlot, where they were instrumented with a real-time location-monitoring ear tag, placed in randomly assigned pens (n = 5 pens/treatment), and monitored for 21 days. During experiment 2, calves in pens were administered the treatment opposite that of experiment 1, returned to their pens without undergoing transportation, and monitored for another 21 days. For each experiment, mean daily distance traveled and percentage time spent near feed (PNF) and water (PNW) were calculated on a pen basis and compared between treatments. RESULTS During experiment 1, mean daily distance traveled, PNF, and PNW did not differ significantly between meloxicam-treated and control calves; however, all 3 behaviors varied significantly by day. During experiment 2, although mean distance traveled was significantly associated with the interaction between day and treatment, it did not differ significantly between meloxicam-treated and control calves within any specific day. Mean PNF and PNW were significantly associated with day only, although no pattern in that effect was evident. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that a single dose of meloxicam prior to transportation did not significantly affect the behaviors of transported and nontransported calves.

Prececal amino acid digestibility of soybean cake in fast- and slow-growing broiler chickens

The objective of the present study was to determine whether there are differences in prececal amino acid digestibility between commonly used slow- and fast-growing broiler strains when the regression approach is applied. ISA J-275 and Ross 308 were selected as common representatives of slow- and fast-growing broiler strains, respectively. The experimental diets with soybean cake at levels of 0, 100, and 200g/kg were offered for ad libitum consumption between 22 and 29 d post-hatch. Titanium dioxide was used as an indigestible marker. Each treatment was tested with six pens comprising 10 birds each. Digesta samples were collected on a pen basis from the distal two-thirds of the intestine section between Meckel's diverticulum and 2cm anterior to the ileocecal-colonic junction. The prececal amino acid digestibility of soybean cake was calculated by linear regression simultaneously for both strains. There was no significant interaction between broiler strain and inclusion level of soybean cake with respect to the prececal CP and amino acid digestibility of complete diets; there was a significant strain effect for 5 out of the 16 measured amino acids. The prececal CP and amino acid digestibility of soybean cake did not differ significantly between strains and was numerically almost identical. The results of the present study provide evidence of the transferability between broiler strains of prececal amino acid digestibility data, determined using the regression approach, thus improving the accuracy of diet formulation without drawbacks.

Effects of Energy Source and Level, and Sex on Carcass and Meat Characteristics in Lambs

ObjectivesThe objective of the study was to investigate concerns of excessively fat lambs in the U.S. by comparing energy source and level, and the sex of lamb, on lamb carcass and meat characteristics.Materials and MethodsEwe (n = 48) and wether (n = 48) lambs were blocked by sex and stratified by initial weight to pen. The three diets were ad libitum whole shelled corn (WSC; AC), 85% of ad libitum intake WSC diet (LC), or an ad libitum alfalfa pellet diet (AA). There were 4 lambs per pen, and 8 replicate pens per dietary treatment. Ewe (n = 24) and wether (n = 24) lambs were harvested on a pen basis during the periods of 7/7/2015 through 8/25/2015 when pens reached an average weight of 59.0 and 63.5 kg, respectively. Carcasses were split between the 12th and 13th rib 24 h postmortem to record carcass measurements. Minolta measurements were taken 24 h postmortem and loin chops were allowed to bloom for 20 min before color measurements were taken. Statistical analysis was conducted using PROC MIXED statement in SAS with diet and sex as fixed effects, diet and sex nested within pen as the random effect, and initial weight and final weight were used as covariates if P 0.05) were found between carcasses for conformation score, lean color and quality score, and quality grade. Minolta L*, a*, and b* values taken from the subcutaneous fat across the top of the shoulders on the carcass were not significantly different (P > 0.05). Similarly, the Minolta L* and a* values of the lean from a butterflied loin chop were not significantly different (P > 0.05). However, loin chop from wether carcasses had greater (P < 0.05) b* values compared to loin chops from ewe carcasses.ConclusionIn conclusion, lambs fed WSC had greater dressing percentages that related to greater hot carcass weights with greater measurements of carcass fat compared to lambs fed alfalfa pellets.

Effect of space allowance and floor type on performance, welfare and physiological measurements of finishing beef heifers

Accommodating cattle indoors during the winter is widely practiced throughout Europe. There is currently no legislation surrounding the space allowance and floor type that should be provided to cattle during this time, however, concerns have been raised regarding the type of housing systems currently in use. The objective of the study was to investigate the effect of space allowance and floor type on performance and welfare of finishing beef heifers. Continental crossbred heifers (n=240: mean initial live; weight, 504 (SD 35.8) kg) were blocked by breed, weight and age and randomly assigned to one of four treatments; (i) 3.0 m2, (ii) 4.5 m2 and (iii) 6.0 m2 space allowance per animal on a fully slatted concrete floor and (iv) 6.0 m2 space allowance per animal on a straw-bedded floor, for 105 days. Heifers were offered a total mixed ration ad libitum. Dry matter intake was recorded on a pen basis and refusals were weighed back twice weekly. Heifers were weighed, dirt scored and blood sampled every 3 weeks. Whole blood was analysed for complete cell counts and serum samples were assayed for metabolite concentrations. Behaviour was recorded continuously using IR cameras from days 70 to 87. Heifers’ hooves were inspected for lesions at the start of the study and again after slaughter. Post-slaughter, carcass weight, conformation and fat scores and hide weight were recorded. Heifers housed at 4.5 m2 had a greater average daily live weight gain (ADG) than those on both of the other concrete slat treatments; however, space allowance had no effect on carcass weight. Heifers accommodated on straw had a greater ADG (0.15 kg) (P<0.05), hide weight (P<0.01) better feed conversion ratio (P<0.05) and had greater dirt scores (P<0.05) at slaughter than heifers accommodated on concrete slats at 6.0 m2. The number of heifers lying at any one time was greater (P<0.001) on straw than on concrete slats. Space allowance and floor type had no effect on the number of hoof lesions gained or on any of the haematological or metabolic variables measured. It was concluded that increasing space allowance above 3.0 m2/animal on concrete slats was of no benefit to animal performance but it did improve animal cleanliness. Housing heifers on straw instead of concrete slats improved ADG and increased lying time; however carcass weight was not affected.

Effect of shade on animal welfare, growth performance, and carcass characteristics in large pens of beef cattle fed a beta agonist in a commercial feedlot.

Feedlot cattle ( = 1,395; BW = 568 ± 43 kg) were used to evaluate the effects of shade on animal welfare, growth performance, and carcass quality during the summer of 2013 in a Kansas commercial feedlot. Seven lots of predominately black steers and heifers (4 and 3, respectively) visually determined to be approaching the final mo on feed were identified, randomly gate-sorted, and allocated to pens located across the feed alley from each other to receive 1 of 2 treatments: 1) Shade (mean shade area = 1.5 m/ animal) or 2) No shade. Shade was provided using a 13-ounce polyethylene fabric and pens were oriented northwest to southeast. The mean starting date was June 13 and the mean days on feed for lots while on the study was 38 d. Cattle were fed a 77.67% DM steam-flaked corn-based diet and had ad libitum access to water throughout the duration of the trial. Zilpaterol hydrochloride (ZIL) was included in the finishing ration at an inclusion rate of 8.3 mg/kg of DM for the last 20 d on feed with a 3 d withdrawal period. Pen floor temperatures (PFT) were measured using an infrared thermometer and prevalence of cattle open-mouth breathing (OMB) was recorded on a pen basis. In addition to shade treatment, the effect of temperature humidity index (THI) on PFT and OMB was analyzed by classifying days as either "Alert" (THI < 79) or "Danger" (THI > 79). On the day of slaughter, pens within a replicate were kept separate through all stages of the marketing channel from loading at the feedlot until stunning at the plant. Pen served as the experimental unit for all measurements. There was a THI × shade treatment interaction for PFT and OMB ( < 0.001) where days classified as "Danger" increased PFT and prevalence of OMB compared to "Alert" days in unshaded but not shaded cattle. Shaded cattle had greater DMI ( = 0.01); however, unshaded cattle had greater G:F ( = 0.05) and therefore no differences were observed in ADG ( = 0.39). Shaded cattle had greater dressing percentage ( = 0.01), although HCW, LM area, fat thickness, marbling score, and quality grade did not differ between treatments ( > 0.05). Heat stress, a significant animal welfare concern and cause of reduced performance in feedlot cattle during the final phase of the feeding period, was alleviated in shaded cattle and illustrates the importance of shade provision as 1 tool to protect the welfare and increase feed consumption in large pens of feedlot cattle during hot summer months.

Evaluating the removal of pigs from a group and subsequent floor space allowance on the growth performance of heavy-weight finishing pigs.

A total of 1,092 finishing pigs (initially 36.3 kg) were used in a 117-d study to evaluate the impact of initial floor space allowance and removal strategy on the growth of pigs up to 140 kg BW. There were 4 experimental treatments with 14 pens per treatment. The first treatment provided 0.91 m per pig (15 pigs/pen). The other 3 treatments initially provided 0.65 m per pig (21 pigs/pen) with 3 different removal strategies. The second treatment (2:2:2) removed the 2 heaviest pigs from pens on d 64, 76, and 95 when floor space allowance was predicted to be limiting. Treatment 3 (2:4) removed the 2 heaviest pigs on d 76 and the 4 heaviest pigs on d 105. Treatment 4 (6) removed the heaviest 6 pigs on d 105. All pigs remaining in pens after removals were fed to d 117. Overall (d 0 to 117), pigs initially provided 0.91 m of floor space had increased ( < 0.05) ADG compared to pigs in pens on the 2:4 or 6 removal strategy, but ADG was not different compared with pigs on the 2:2:2 removal strategy. Total BW gain per pen was greater ( < 0.05) for pens initially stocked at 0.65 m compared to pens initially stocked at 0.91 m. Feed usage per pen was less ( < 0.05) for pens initially stocked at 0.91 m compared to pens initially providing 0.65 m of floor space and on removal strategies; however, feed usage per pig was greater ( < 0.05) for pigs initially stocked at 0.91 m compared to pigs initially stocked at 0.65 m and on removal strategies. Feed usage, on a pig or pen basis, was less ( < 0.05) for pigs on the 2:2:2 removal strategy compared to pigs on the 2:4 or the 6 removal strategy. Income over feed and facility cost (IOFFC) was less ( < 0.05) for pigs initially provided 0.91 m compared to pigs initially provided 0.65 m and on removal strategies. Also, IOFFC was less ( < 0.05) for pigs on the 2:2:2 compared to the 2:4 and 6 removal strategies. In conclusion, increasing the floor space allowance or the time points at which pigs are removed from the pen improved the growth of pigs remaining in the pen; however, IOFFC may be reduced because fewer pigs are marketed from each pen (pigs stocked at 0.91 m throughout the study) or from reducing total weight produced (2:2:2 removal strategy).

Effect of diets containing enzyme supplements and microwave-treated or untreated wheat on inositol phosphates in the small intestine of broilers

The objective was to study the effect of diets containing microwave-treated wheat and supplemental enzymes on myo-inositol 1,2,3,4,5,6-hexakis (dihydrogen phosphate) (InsP6) hydrolysis and the presence of inositol phosphate isomers (InsPs) in the small intestine of broilers. We assigned 16-day-old broilers to 48 pens of 15 broilers each (n=8 pens per treatment) in a 2×3 factorial arrangement of treatments. Birds were fed a wheat-soybean meal diet that was low in phosphorus (4.8g/kg dry matter) and that contained either microwave-treated (BDTW) or untreated (BDUTW) ground wheat. Diets were used without an enzyme supplement or after supplementation with an E. coli-derived phytase, alone or in combination with a xylanase. On d 23, samples of digesta from the duodenum/jejunum and lower ileum were pooled per segment on a pen basis, freeze-dried, and analyzed for P, InsPs, and the marker TiO2. Statistical significance was evaluated by a two-way analysis of variance. Microwaving affected dietary intrinsic phytase activity (BDUTW: 623U/kg; BDTW: 121U/kg). Interactions between microwave treatment and enzyme supplementation were found for InsP6 hydrolysis (P=0.048) and P net absorption (P=0.004) in the ileum. In both segments, InsP6 hydrolysis (duodenum/jejunum: P=0.004, ileum: P=0.002) and P net absorption (P≤0.001) were significantly increased by supplementation of phytase, but no further increments were caused by supplemental xylanase. The significant interaction on InsP6 hydrolysis in the ileum was due to a higher InsP6 hydrolysis for BDTW (78%) than for BDUTW (69%) in the absence of supplemental phytase. In birds that were fed the phytase-supplemented diets, microwave treatment of wheat had no effect on InsP6 hydrolysis. The significant interaction on P net absorption in the ileum was due to reduced P net absorption by microwave treatment in the presence but not absence of supplemental phytase. Broilers and their gut microbiota have a high potential to hydrolyze InsP6 in the intestine. Microwaving may have disrupted wheat aleurone structures in ways that increased accessibility of InsP6 and may have encouraged higher levels of activity among specific phytases of microbial or endogenous mucosal origin in the lower small intestine. Accumulation of InsP3 in the duodenum/jejunum for microwave-treated diets suggested that such treatment reduces the effectiveness of the phosphatases that further degrade InsP3 (P=0.004).

Re-evaluating Floor Space Allowance and Removal Strategy Effects on the Growth of Heavyweight Finishing Pigs

This study was performed to evaluate the impact of initial floor space allowance and various topping strategies (removal of the heaviest pigs in a pen prior to marketing the finishing group) on the growth performance of heavyweight finishing pigs. A total of 1,092 pigs (initially 80.1 lb) were allotted to one of 4 experimental treatments with 14 pens per treatment. The first treatment stocked pigs at 9.7 ft2 (15 pigs/pen) throughout the study. The other three treatments initially stocked pigs at 6.9 ft2. The second treatment (2:2:2) topped the two heaviest pigs on d 64 (203 lb), d 76 (227 lb), and d 95 (264 lb), which coincided with the time floor space allowance became limiting, as predicted by Gonyou et al. (2006). The third treatment (2:4) topped the 2 heaviest pigs and the 4 heaviest pigs at an average BW of 240 (d 76) and 280 lb (d 105), respectively. The fourth treatment (6) topped the 6 heaviest pigs at an average BW of 280 lb (d 105). All pigs remaining in pens after topping events were marketed on d 117 of the study. Overall (d 0 to 117), pigs in pens stocked at 9.7 ft2 had increased (P < 0.05) ADG compared to pigs in pens on either the 2:4 or 6 topping strategies, but ADG was not different from pigs in pens on the 2:2:2 topping strategy. This suggests that prediction equations developed by Gonyou et al. (2006) for ADG are useful for predicting the effects of floor space on heavyweight pig ADG. Pigs in pens stocked at 9.7 ft2 had increased (P < 0.05) ADFI compared to pigs in pens initially stocked at 6.9 ft2 regardless of topping strategy. Total weight gain per pen was greater (P < 0.05) for pens initially stocked at 6.9 ft2 compared to pens stocked at 9.7 ft2; however, total weight gain per pig was greater for pigs in pens stocked at 9.7 ft2 compared to pigs in pens initially stocked at 6.9 ft2. Pigs in pens on the 2:2:2 topping strategy had less weight gain (P < 0.05) than pigs in pens on the 6 topping strategy. Feed usage per pen was decreased for pens stocked at 9.7 ft2 compared to those initially stocked at 6.9 ft2; however, per pig feed usage was increased (P < 0.05) for pigs in pens stocked at 9.7 ft2 compared to pigs in pens initially stocked at 6.9 ft2. Pens on the 2:2:2 topping strategy had less (P < 0.05) feed usage, either on a pen or pig basis, than those on the 2:4 or the 6 topping strategy. Interestingly, there was a tendency (P < 0.10) for pigs in pens on the 2:4 topping strategy to have less feed usage than pigs in pens on the 6 topping strategy. Income over feed and facility cost (IOFFC) was decreased (P < 0.05), either on a pen or pig basis, for pens stocked at 9.7 ft2. Pigs in pens on the 2:2:2 topping strategy had numerically less IOFFC when revenue was high and feed cost was low compared to pigs in pens on the 2:4 or 6 topping strategy. In conclusion, increasing the floor space allowance or the time points at which pigs are removed from the pen improved the performance of pigs remaining in the pen; however, IOFFC may be reduced due to fewer pigs marketed from each pen (in the case of lower stocking density) or from reducing total weight produced (in pens where pigs are topped earlier at lighter weights).

Dietary chromium picolinate of varying particle size improves carcass characteristics and insulin sensitivity in finishing pigs fed low- and high-fat diets

The aim of the present study was to evaluate the effect of the different-sized particles of chromium (Cr) picolinate (CrPic) and dietary fat on growth performance, carcass traits and insulin sensitivity of finishing pigs. Ninety-six Large White × Landrace gilts were stratified on bodyweight, housed in pens of three pigs and then, on a pen basis, randomly allocated to eight treatment groups in a 2 × 4 factorial design for 6 weeks. The respective factors were dietary fat (2.2% or 5.7%) and dietary CrPic (0 mg/kg, 400 mg/kgnormal-size CrPic, 400 mg/kg 1-μm CrPic (μCrPic), or 400 mg/kg 100-nm CrPic (nCrPic)). Over the first 21 days, average daily gain (ADG) was increased by dietary CrPic (0.94 vs 1.01 kg/day, P = 0.021), although there was no difference (P = 0.17) between the CrPic particle sizes. High dietary fat also increased ADG over this period (0.96 vs 1.03 kg/day, P = 0.013). However, the responses to both dietary CrPic and fat diminished over time and so there was no effect of CrPic (P = 0.35) or fat (P = 0.93) on ADG over the full 42 days. Dietary CrPic increased carcass weight and muscle depth and decreased P2 backfat. Furthermore, dietary Cr decreased plasma insulin (7.66 vs 5.09 mU/L, P = 0.018) and the homeostatic model assessment (1.25 vs 0.82, P = 0.009), indicating an improvement in insulin sensitivity. In conclusion, dietary Cr can increase ADG and improve carcass traits and insulin sensitivity in lean pigs. There were few differences among particle sizes, possibly because the response to dietary CrPic may already be maximised at 400 mg/kg.

Comparison of growth performance, carcass characteristics and meat quality of korean local chickens and silky fowl.

This study was conducted to compare growth performance, carcass characteristics and meat quality of 4 breeds of local chicken. A total of 480 1-d-old chicks were distributed to 16 pens, with 4 treatments of breed, 4 replicates and 30 chicks per pen. Three Korean local breeds of white-mini broiler, Hanhyup-3-ho, and Woorimatdag, and a breed of silky fowl were raised under identical rearing and feeding conditions for 31-d, 37-d, 36-d, and 59-d, respectively. The BW and feed consumption on a pen basis were weekly measured for all pens, and ADFI, ADG and gain:feed were calculated for each pen. The ADFI and ADG of 3 breeds of Korean local chicken were greater than those of silky fowl (p<0.05). Within the Korean local breeds, ADFI of white-mini broiler was the highest (p<0.05), and ADG of Hanhyup-3-ho and white-mini broiler was the highest (p<0.05). Gain:feed of silky fowl was less than that of the 3 breeds of Korean local chicken. The carcass and breast yield of white-mini broiler were the greater than those of other breeds (p<0.05). The breast meat color (CIE L*, a*, and b*) of 3 breeds of Korean local chicken were higher than that of silky fowl (p<0.05). The breast meat of Hanhyup-3-ho had greater cooking loss (p<0.05), whereas water holding capacity and pH were less than those of other breeds (p<0.05). The color score of 3 breeds of Korean local chicken was higher than that of silky fowl (p<0.05). Woorimatdag had a higher score on tenderness (p<0.05), whereas flavor score was less than that of other breeds (p<0.05). In conclusion, 4 local breeds of chicken have some unique features and seem to have more advantages, and this information can help consumers who prefer healthy and premium chicken meat.

Growth, carcass characteristics, and profitability of organic versus conventional dairy beef steers

Bull calves (n=49), born at the University of Minnesota West Central Research and Outreach Center (Morris) between March and May 2011, were used to compare growth measurements and profitability of conventional and organic dairy steers. Calves were assigned to 1 of 3 replicated groups at birth: conventional (CONV; n=16), organic (pasture and concentrate; ORG; n=16), or organic grass only (GRS; n=17), and analysis of variables was on a pen basis. Breed groups of calves were Holstein (HO; n=9); Holsteins (n=11) maintained at 1964 breed average level; crossbreds (n=19) including combinations of HO, Montbéliarde, and Swedish Red; and crossbreds (n=10) including combinations of HO, Jersey, Swedish Red, and Normande. The CONV steers were fed a diet of 80% concentrate and 20% forage. The ORG steers were fed a diet of organic corn, organic corn silage, and at least 30% of their diet consisted of organic pasture during the grazing season. The GRS steers grazed pasture during the grazing season and were fed high-quality hay or hay silage during the nongrazing season. Intakes of a total mixed ration were recorded daily with herd management software. A profit function was defined to include revenues and expenses for beef value, feed intake, pasture intake, health cost, and yardage. The GRS (358.6kg) steers had lesser total gains from birth to slaughter than ORG (429.6kg) and CONV (534.5kg) steers. Furthermore, the GRS (0.61kg/d) steers had lesser average daily gain from birth compared with ORG (0.81kg/d) and CONV (1.1kg/d) steers. The GRS and ORG steers had smaller rib eye area (49.5 and 65.8cm2, respectively) compared with CONV (75.4cm2) steers. For profitability, GRS steers had 43% greater profit than CONV steers due to organic beef price premiums and lower feed costs. On the other hand, ORG steers had substantially less profit than CONV steers. The higher cost of production for the ORG steers is due to the extreme high value of organic corn. The results of the current study illustrate the economic potential of alternative strategies for growing and marketing male offspring of organic dairy cattle in the Midwest.

Immunocastration with Improvac™ reduces aggressive and sexual behaviours in male pigs

Surgical castration of male pigs is a common practice to reduce the risk of boar taint, an accumulation of pheromones in the muscles of pigs giving an undesirable odour to the pork of entire boars. Castration is not widely practiced in the UK for welfare reasons and indeed, assurance schemes will not allow castrated animals into their markets. Immunocastration maintains entire male pigs in a pre-pubescent state and as such prevents boar taint in the meat. The aim of this study was to investigate the effect of early vaccination with a gonadotrophin releasing factor (GnRF) vaccine Improvac™ (Pfizer Ltd) on aggressive and sexual behaviour of group housed male pigs. Pigs were housed in 8 groups each containing 9–10 pigs per group. Male pigs were assigned to two groups: a control group administered 2 doses of a placebo (n=38) and a vaccinated group administered 2 doses of Improvac™ (n=38). Behavioural observations began one week after the second dose when the pigs were 16 weeks old. Pigs were video recorded for 30min once a week for 10 weeks.Video recordings were reviewed and the frequency of behaviours associated with sex and aggression were recorded on a pen basis. The activity of pigs was also recorded every 5min during the 30min observation period to determine any differences between vaccinated and control groups. A generalised linear mixed model was used for data analysis. The results of the model showed a significant difference between vaccinated and control groups for knocking (P<0.05), fighting (P<0.05) and mounting (P<0.01) behaviours. Vaccination had no significant effect on the activity of pigs during the recording period. In conclusion early immunocastration of pigs significantly reduces the occurrence of unwanted aggressive and sexual behaviours compared with unvaccinated control male pigs.

The effect of combining different environmental enrichment materials on enrichment use by growing pigs

EU legislation requires that growing pigs are provided with suitable materials that satisfy their needs for investigation and manipulation. Although commercial pig keepers have tried a variety of different enrichment materials and methods of presentation, the benefits to the pig have not always been clear. The aim of this paper was to determine: (1) the extent to which provision of separate enrichment materials gives predictable additive increases in occupation time, (2) whether there is consistency in the relative use of different enrichment materials over time and, if so, and (3) whether a rapid methodology could be used to evaluate the relative enrichment value of a particular material for growing pigs. A total of 36 growing pigs (mean liveweight 36kg) were used, housed in 12 groups of 3 in part-slatted pens in a controlled environment building. Four enrichment materials with different properties were compared: two hanging objects suspended above the pen (sisal rope, R and metal chain, C) and two foraging substrates provided in a trough (sawdust, S and wood shavings, W). The materials were presented in pairs, in all six combinations (CR, CW, CS, RW, RS and WS) with each group of pigs exposed to one combination of materials for five days followed by the other two materials for a further five days. Time interacting with each enrichment material was determined on a per pen basis. The results showed that although the pigs very quickly habituated to all of the enrichment materials, they spent a greater proportion of time interacting with some materials than others (e.g. rope: 0.17, sawdust: 0.04; P<0.001). Pairing the four different enrichment materials in different combinations affected the relative proportion of time pigs spent with different materials. For example, pigs spent relatively more of enrichment-directed time with the chain when it was paired with sawdust compared to when it was paired with shavings (0.82 versus 0.46 of total enrichment-directed time; SEM 0.078, P<0.01). However, for all materials there was consistency in the absolute level of interaction over the 5-day test period, with proportion of total time engaged with a given material not significantly different in different pairings. It is concluded that, for the materials used in the current study at least, use of enrichment materials is additive and relatively independent. The findings of this study suggest that a simple paired test, where any potential new enrichment material is presented alongside a material of known occupational value (to avoid any bias due to habituation, the test animals should be naïve to both enrichment materials), could be used to predict the enrichment value of the new material.

Short-term increases in stocking density affect the lying and social behavior, but not the productivity, of lactating Holstein dairy cows

Reduced access to resources because of increased stocking density may have a detrimental effect on the behavior of the lactating dairy cow. The objective of this study was to determine the short-term responses in behavior, productivity, fecal cortisol metabolites, and udder and leg hygiene of lactating Holstein dairy cows housed at stocking densities of 100 (1 cow per freestall and headlock), 113, 131, and 142%. Multiparous cows (n=92) and primiparous cows (n=44) were assigned to 1 of 4 pens (34 cows per pen) in a 4-row freestall barn. Pens were balanced for parity, milk production, and days in milk. Stocking densities were imposed for 14d using a 4 × 4 Latin square design. Time spent feeding and time spent ruminating were quantified by 24h of direct observation of focal cows (n=12 per pen) beginning at 0800h on d 11 of each period. Data loggers recorded lying behavior (time and bouts) from the same focal cows per pen at 1-min intervals during the final 5d of each period. Fecal cortisol metabolites were quantified from samples collected on d 13 and 14 of each period from the same focal cows. Displacements from the feed barrier were recorded on a pen basis after 9 milkings over the last 4d of each period. Productivity was assessed on a pen basis from milk yield (recorded from d 10 to 14 of each period) and milk components (quantified from composite samples collected on d 12 of each period). Milk composition was further analyzed for milk fatty acid profiles, which were determined from a subset (n=6 per pen) of the focal cows. Data were analyzed using the MIXED procedure of SAS, with the pen (n=4 per treatment, except displacements where n=3 per treatment) as the experimental unit. Feeding and ruminating (h/d) did not differ among treatments. Lying time was reduced at stocking densities of 131 and 142%, relative to 100 or 113%. Lying bouts were not affected by treatment. Stocking densities of 131 and 142% reduced the percentage of time cows spent ruminating within a freestall relative to 100%. Displacements from the feed bunk increased linearly across treatments. Fecal cortisol metabolites, udder hygiene score, milk yields, milk composition, and milk fatty acids did not differ among treatments. Decreased lying time and increased aggression at the feed bunk suggest that an alteration of the time budgets of lactating dairy cows may occur at higher stocking densities, but it is unclear at what point these changes might have further biological consequences.

A fat based rumen protection technology post-ruminally delivers a B vitamin complex to impact performance of multiparous Holstein cows

Our previous research demonstrated that milk production of early lactation dairy cows benefits from postruminally delivered B vitamins in addition to those supplied in rumen microbes. In this study, our objective was to determine effects of supplementation of a complex of ruminally protected B vitamins (BV), using a fat based rumen protection technology, of biotin, pantothenic acid, folic acid, cyanocobalamin and pyridoxine, to dairy cows through 200 days in milk (DIM) on reproductive performance through 200 DIM, as well as milk production and composition through 180 DIM. Multiparous Holstein cows calving between November 2007 and April 2008 were assigned to one of two treatments as they moved from a common fresh pen to one of four early lactation pens at 22±2.1 DIM. Two pens were fed the early lactation control diet (C) and two were fed the same diet with BV supplementation. Cows were observed for heat daily at the morning ‘lock’ and bred each morning by artificial insemination. Pregnancy was diagnosed by rectal palpation and yields of milk and milk composition were measured monthly. A total of 949 cows, 448 C and 501 BV, provided data for statistical analyses of reproduction and production response parameters. Body condition score (BCS) was determined in a subgroup of 200 cows (i.e., 50/pen) at 40 and 100 DIM. Dry matter (DM) intake was calculated on a pen basis in four discrete time blocks of 21d each. First service conception rate was higher with BV supplementation 42d after insemination (358cows/1000 cows versus 406cows/1000 cows; P=0.03), which was maintained at 150 (334cows/1000 cows versus 381cows/1000 cows; P=0.04) and 200 DIM (334cows/1000 cows versus 381cows/1000 cows; P=0.06). However because cumulative pregnancy rate at 150 and 200 DIM was not impacted by BV feeding, it is clear that cows became pregnant sooner, but that more cows did not become pregnant, through 200 DIM with BV supplementation. Cows in the BV group were 20% less likely (P=0.046) to be culled through 200 DIM, but the incidence of mastitis was not influenced by treatment. Supplementation with BV tended to reduce (P=0.058) DM intake (26.0kg/d versus 25.6kg/d) but had no impact on milk (44.5kg/d versus 45.0kg/d) or milk component production through 180 DIM. There were no treatment differences in BCS change between 40 and 100 DIM. Supplementation of this novel ruminally protected BV complex positively effected aspects of reproductive performance, while reducing culling in these early lactation high producing multiparous dairy cows.

Low protein diets and rumen-protected conjugated linoleic acid increase nitrogen efficiency and reduce the environmental impact of double-muscled young Piemontese bulls

Effects of diets differing in crude protein (CP) concentrations, top-dressed or not with 80g/d of rumen-protected conjugated linoleic acid (rpCLA), on N efficiency of double muscled (DBM) Piemontese bulls were studied using four experimental diets being: high CP, HP; high CP plus rpCLA, HPrpCLA; low CP, LP; low CP plus rpCLA, LPrpCLA. The HP diets (145g/kg DM of CP) were similar those used commercially and the LP diets (108g/kg DM of CP) were used to evaluate effects of lower dietary CP levels on intake, digestibility and body retention of nutrients, as well as N excretion. Forty-eight young bulls (237±24.4kg body weight (BW)), housed in 12 pens were fed one of the four experimental diets. Bulls were slaughtered at 668±56.2kg BW, after 332 days on their diet. Dry matter intake was measured daily on a pen basis and bulls were individually weighed monthly. Blood, rumen fluid and faecal samples were collected from each bull at 63, 179 and 283 days. Empty body composition at the start and the end of the feeding period was estimated using equations developed on DBM bulls and from the composition of the 5th rib collected at slaughter. Nitrogen balance was computed using a mass balance approach. Lowering of the diet CP level reduced both blood urea N (P<0.001) and rumen ammonia N (P<0.001) concentrations, but did not influence organic matter digestibility or body retentions of protein or fat. Compared to HP, LP increased N efficiency (N retained/N consumed) from 0.17 to 0.23 (P<0.001), likely due to more extensive N recycling. Nitrogen efficiency was also influenced by a CP×rpCLA interaction (P=0.047), wherein bulls fed rpCLA used N more efficiently than bulls not receiving rpCLA when fed the LP diet, but had similar N efficiency when fed the HP diet. This suggests that CLA could exert some metabolic protein sparing effects, particularly under conditions of dietary CP shortage with respect to the bull requirements. The magnitude of the increase of N efficiency with LP compared to HP diets has a relevant impact on the DBM Piemontese bull production system, particularly where the load of N per unit land area is restricted by law. With respect to the conventional HP diet, use of LP without or with rpCLA would increase BW production per unit of N excreted by 31% and 43%, respectively.