A comparative study of the preventive use of tilmicosin phosphate (Pulmotil premix) and Mycoplasma hyopneumoniae vaccination in a pig herd with chronic respiratory disease

This study was conducted to compare the effects of a preventive in-feed medication programme using tilmicosin (Pulmotil 200 premix, Elanco Animal Health) at 200 p.p.m. with those of Mycoplasma hyopneumoniae (Mh) vaccination programme (Stellamune Mycoplasma, Pfizer Animal Health). A pig herd with chronic respiratory disease in which infection with Mh played an important role was selected, and a total of 204 piglets were randomly allocated to either the medication (P) or the vaccination (V) group. Pigs in the P group received medicated feed for 3 weeks after weaning (days 34-55), and for 2 weeks late in the nursery period (days 77-98). The piglets in the V group were vaccinated twice intramuscularly, at 4 and 22 days of age. The two groups were compared on the basis of average daily gain (ADG), feed conversion rate (FCR), additional curative medication days (CMD), overall mortality (major variables), a coughing index, pneumonia lesions, and serology against Mh, influenza H1N1 and influenza H3N2 viruses, Actinobacillus pleuropneumoniae (App) and porcine reproductive and respirator, syndrome virus (PRRSV) (minor variables). No significant differences (P > 0.05) were observed for ADG (555 g/day in P group; 567 g/day in V group), FCR (2.64 in P group; 2.41 in V group) and mortality rate (11% in P group; 7% in V group). The average number of additional curative medication days (CMD) per pig was significantly higher (P < 0.01) in the P group (1.5) than in the V group (0.58). At slaughter age, the serological results and the prevalence of macroscopic lung lesions were comparable in the two groups (P > 0.05). With the exception of CMD, the preventive use of tilmicosin at this swine farm was found to confer similar beneficial effects to Mh vaccination.     

Comparative growth performance of pigs immunised with a gonadotrophin releasing factor vaccine with surgically castrated pigs and entire boars raised under conventionally managed conditions

The objective of this study was to determine the effect of using a gonadotrophin releasing factor (GnRF) vaccine on growth performance of male pigs. Vaccinated pigs were compared with surgically castrated pigs and entire males under conventionally managed farm conditions. Male pigs were randomly assigned to three treatment groups: pigs surgically castrated during the first week of life (group "C", n=274), pigs immunised twice during the fattening period with a GnRF vaccine, the first when 13-14 weeks of age and the second when 20-21 weeks of age (group "V" n=280) and entire males (group "E", n=56). Average daily weight gain (ADG) was measured during the study. Additionally, feed conversion ratio (FCR) as defined by feed intake/weight gain and feed consumption was assessed during the fattening period. No difference in the ADG during the fattening period could be determined between "C" and "V". From the start of the study until slaughter at study day 160/173 the ADG in group "E" was lower (625 g/day; P) than in group "C" (681 g/day; P < 0.001) and group "V" (675 g/day; P < 0.01). The FCR during the fattening period until study day 160, three days before the first batch of pigs were slaughtered at 24-25 weeks of age, was higher in group"C" (2.72 kg feed intake/kg weight gain) compared with group "V" (2.44 kg feed intake/kg weight gain; P < 0.001) and group "E" (2.44 kg feed intake/kg weight gain; P <0.01). Pigs in group "V" performed similarly to those in group "E" until the second vaccination (day 135) after which time they showed a substantial increase in feed intake and ADG, while retaining an FCR advantage over group C.     

Efficacy of Tilmicosin Phosphate (Pulmotil® Premix) in Feed for the Treatment of a Clinical Outbreak of Actinobacilluspleuropneumoniae Infection in Growing–Finishing Pigs

A double‐blind randomized clinical trial was carried out to investigate the efficacy of tilmicosin (Pulmotil^® premix) for the treatment of a clinical outbreak of Actinobacillus pleuropneumoniae infection in growing–finishing pigs. The effects of tilmicosin administration in the feed at 400 mg/kg and an injection therapy of clinically diseased pigs with long‐acting oxytetracycline (Terramycine^® LA) at 20 mg/kg bodyweight were compared. Both groups, totalling 147 pigs, were compared during a medication period of 15 days and a post‐medication period of 11 days by means of different clinical and performance parameters. During the medication period, the tilmicosin group showed a significant advantage with respect to the number of new disease cases (P < 0.01), and a non‐significant advantage regarding the number of removed pigs (P=0.16), the number of sick pigs that recovered (P=0.27) and the time to recovery (P=0.42). During the post‐medication period, the pigs of the tilmicosin group showed numerical non‐significant benefits (P > 0.05) with respect to the clinical parameters. During the overall study period (26 days), the average daily gain and the feed conversion ratio were both significantly (P < 0.01) better in pigs from the tilmicosin group compared with pigs from the oxytetracycline group. This study demonstrated that in‐feed medication of tilmicosin at a dosage of 400 mg/kg is efficacious for the treatment of a clinical respiratory disease outbreak of A. pleuropneumoniae infection in growing–finishing pigs. Compared with oxytetracycline injection of clinically diseased pigs, the tilmicosin treatment is particularly beneficial in the prevention of new disease cases while increasing or maintaining the performance of the pigs.     

The relationship between infectious and non-infectious herd factors with pneumonia at slaughter and productive parameters in fattening pigs

This paper explores the relationship between infectious and non-infectious herd factors with the occurrence of pneumonia at slaughter and productive parameters in fattening pigs on 39 fattening herds. A questionnaire was used to obtain environmental and management factors (non-infectious factors). Blood samples and lungs were obtained from 35 pigs in each herd at slaughter. Serological testing was performed for antibodies against three respiratory pathogens (infectious factors): porcine reproductive and respiratory syndrome virus (PRRSV), Mycoplasma hyopneumoniae (Mh) and Aujeszky's disease Virus-gE protein (ADV-gE). Lung lesion classifications were catarrhal-purulent bronchopneumonia (CPBP), pleuropneumonia (PLP) and pleuritis. A mean lesion value (MLV) was calculated for each lesion. ANOVA and logistic regression assessed statistical associations among MLV, average daily gain (ADG) and feed conversion ratio (FCR) (dependent variables) with infectious and non-infectious factors (independent variables). Mh vaccination was associated with a significant decrease in CPBP; high Mh seroprevalences was associated with an increased level of CPBP. FCR was negatively related with high seroprevalences for ADV-gE and Mh. No significant associations were seen for ADG.     

色氨酸对5～10周龄扬州鹅生长性能和屠宰性能的影响

选用270只21日龄的扬州公鹅,随机分成6组,每组3个重复,每个重复15只鹅。采用2×3二因子试验设计,采用两种饲喂方式(自由采食和90%限制饲喂,限制饲喂组鹅饲料供给量为前一天自由采食组饲料消耗量的90%)和低、中、高3个色氨酸(Trp)水平(含量分别为0.14%,0.22%和0.30%),分别对3个不同生长阶段的生长性能和屠宰性能指标进行测定。结果表明,在28～42日龄,与低、高Trp组相比,中Trp组扬州鹅平均日采食量和平均日增重显著提高(P<0.05),饲喂方式和Trp水平对扬州鹅平均日采食量、平均日增重和饲料转化率有交互作用(P<0.05);在42～56日龄,自由采食组扬州鹅平均日采食量和饲料转化率极显著高于限制饲喂组(P<0.01),平均日增重显著高于限制饲喂组(P<0.05)。与低、高Trp组相比,中Trp组扬州鹅平均日采食量显著提高(P<0.05),Trp水平对平均日增重和饲料转化率无显著影响(P>0.05),饲喂方式和Trp水平对扬州鹅平均日采食量有交互作用(P<0.05);在56～70日龄,Trp水平对扬州鹅平均日采食量、平均日增重和饲料转化率均无显著影响(P>0.05)。饲喂方式和Trp水平对扬州鹅平均日增重和饲料转化率有交互作用(P<0.05);在28～70日龄,自由采食组扬州鹅平均日采食量和平均日增重极显著高于限制饲喂组(P<0.01)。与低、高Trp组相比,中Trp组扬州鹅平均日采食量和平均日增重显著提高(P<0.05),而Trp水平对饲料转化率无显著影响(P>0.05),饲喂方式和Trp水平对扬州鹅平均日采食量和平均日增重有交互作用(P<0.05)。自由采食组扬州鹅全净膛率、胸肌率和腹脂率显著高于限制饲喂组(P<0.01),随着Trp水平的增加,扬州鹅胸肌率显著增加(P<0.01),而Trp水平对其他屠宰性能指标无显著影响(P>0.05),饲喂方式和Trp水平对扬州鹅腹脂率有交互作用(P<0.01)。由此可知,饲粮中Trp水平过低或过高均会对扬州鹅生长性能产生不利影响,并且这种不利的影响具有阶段性,因此日粮添加适当水平的Trp能够一定程度改善扬州鹅生长性能。     

Efficacy of Sarafloxacin in Broilers after Experimental Infection with Escherichia coli

Infections of chickens with Escherichia coli serotypeO78 can be treated with the antibiotic sarafloxacin. Three experiments were conducted on the administration of this drug to chickens that had been experimentally infected with E. coli. The birds were monitored for 10 days after infection for their average daily gain (ADG) and feed conversion ratio (FCR), and the post-mortem pathology was assessed. In the first experiment, sarafloxacin (20 mg/L, equivalent to 5 mg/kg live weight per day), given in the drinking water for 3 days after infection, led to a reduction in the mortality from 75% to 27%, but the ADG of the treated birds was still less than that of the uninfected controls. In the second experiment, when the sarafloxacin was administered at the same dose in the water but over only 2 h, there was also a considerable reduction in mortality, and the ADG and the FCR also improved significantly. In the third experiment, the dose dependence of the drug was tested. The birds were given 5 and 10 mg/kg per day sarafloxacin in each group, starting within 2 h after infection. This rapid administration of the drug completely prevented mortality, while the ADG and FCR were similar to those of the uninfected controls.     

Evaluation of Mycoplasma hyopneumoniae inactivated vaccine in pigs under field conditions

An inactivated vaccine prepared from broth culture supernatant of Mycoplasma hyopneumoniae with an aluminum adjuvant was evaluated in three herds (herd A: specific pathogen-free herd, herd B: high health status herd with no clinical signs of respiratory infection, herd C: low health status herd with serious epidemiological and economical problems). A total of 212 pigs from the three herds were divided into two groups. One group was injected twice with the vaccine at 4-week intervals and the other was a control group. No adverse reactions were noted following the vaccinations either systematically or locally in any of the vaccinated pigs from any of the herds. In herd A, the vaccination provided antibody response within 4 weeks after the second vaccination and antibody responses continued for more than 12 weeks. In herds B and C, the number of pigs with lung lesions, mean percentage of lung lesions, and the numbers of M. hyopneumoniae recovered from pigs at slaughter in the vaccinated group were significantly (P < 0.05) reduced compared to the control group. Furthermore, vaccination resulted in improved average daily weight gain (ADG), improved feed conversion ratio (FCR), and improved days to market weight in herd C, whereas no difference in growth performance was shown in herd B. It is suggested that the inactivated vaccine prepared from broth culture supernatant of M. hyopneumoniae is effective in reducing clinical signs and lung lesions. Also, vaccination resulted in improved growth performance in herds where clinical signs and economic losses were significant.     

不同能量水平对羊生产性能及激素水平的影响

选用山羊和绵羊各21只,研究能量水平对羊采食量(DMI)、日增重(ADG)、饲料转化率(FCR)、胰岛素、生长激素和孕酮浓度的影响。结果表明:绵羊的DMI显著大于山羊的(P<0．05),低能量水平下,绵羊的DMI显著大于山羊的(P<0．05)。绵羊的ADG显著高于山羊的(P<0．05),高能量水平下两种羊的ADG显著高于低能量水平的(P <0．05),FCR在绵羊与山羊之间、不同能量水平之间及互作之间都不显著(P>0．05)。试验前期山羊血清胰岛素水平显著大于绵羊的(P<0．05),在低能量水平下,山羊的血清胰岛素浓度显著高于绵羊的(P<0．05)。试验前期山羊的孕酮水平显著高于绵羊的(P<0．05),高能量水平下的孕酮极显著地高于中、低能量水平下的孕酮(P<0．01),中等能量水平下,山羊的孕酮浓度显著高于绵羊的(P<0．05)。     

Potential value of tedera (B. bituminosa) as high protein resource for poultry feed

Bituminaria bituminosa (C.H. Stirt.) is a drought tolerant legume that grows spontaneously in subtropical areas: Canary Islands (Spain) and in North African and Mediterranean regions, traditionally used as forage for ruminants. The aim of this research was to investigate the potential of B. bituminosa as a high protein resource for poultry feed by means of feed intake, growth, feed conversion rate (FCR), protein efficiency ratio (PER), and the influence of B. bituminosa feed form (fresh green and dried) on the preference by chicks. B. bituminosa showed higher crude protein content (CP), neutral detergent fiber (NDF), and gross energy than commercial feed. Average daily feed intake (ADFI) for the commercial feed group (control group) was higher than ADFI of the B. bituminosa group (experimental group). However, both groups had no significant differences in total crude protein intake, total NDF intake, average daily gain (ADG), FCR, and PER. The poultry’s preference for fresh green B. bituminosa was higher than for dry B. bituminosa. Our results suggest that B. bituminosa (tedera) could be an alternative feedstuff in tropical countries or where protein sources are scarce and costly.

     

Broiler responses to digestible threonine at different ages: a neural networks approach

Three experiments were conducted with broiler chickens to evaluate the effects of digestible threonine (DThr) and crude protein (CP) on their performance at three different phases of age: 1–14, 15–28 and 29–42 days. The measured traits included the following: average daily gain (ADG), feed intake (FI), feed conversion ratio (FCR), carcass crude protein (CCP), body lipid (BL), feather weight gain (FWG), protein deposited in feather (FCP), carcass plus feather protein (CFCP), carcass Thr deposition (CDThr) and nitrogen excretion (NE). A dilution technique was used to create seven diets (with eight replicates) increasing the DThr content from 1.5 to 10 g/kg of diet for phase 1, 1.3–8.9 g/kg of diet for phase 2, and 1.2–8.2 g/kg of diet for phase 3. Data measured were imported into neural networks (NNs) to: (i) predict the measured traits in response to DThr and CP, (ii) rank the importance of DThr and CP on these traits through sensitivity analysis and (iii) find the optimal levels of DThr and CP that lead to the desired (maximum or minimum) responses. For each trait investigated, 50 different random groups of data were generated using a bootstrapping method. These 50 data groups were then used to develop 50 separate NNs which were subsequently combined to construct the final ensemble NN model. In general, accuracy of the models constructed was acceptable, although models of high (ADG, FCR, CFCP, BL, DThr and NE; 0.64 ≤ R² ≤ 0.99) and low (CCP, FWG and FCP; 0.26 ≤ R² ≤ 0.79) accuracy were obtained. All models developed showed the greatest sensitivity to DThr. This may be explained by the dilution technique diet preparation used in these experiments. Optimization results showed decreases in optimal values of DThr and CP with increasing age for all traits. The highest level of DThr was suggested for minimum BL, followed by minimum FCR, maximum ADG, maximum CFCP, minimum NE and maximum CCP respectively. Results showed that the optimal values of DThr for minimum FCR in phases 1–3 were 8.5, 7.4 and 6.4 g/kg of diet, while these values for maximum ADG were 8.2, 7.2 and 6.4 g/kg of diet respectively.     

Effect of quantitative feed restriction on broiler performance

The objective of the current study was to determine the effect of quantitative feed restriction on the performance of broilers. A total of 270 unsexed broilers were randomly allocated to three treatments: with no feed restriction (T1), one week (T2) and two (T3) weeks of feed restriction from 22 days of age and then fed ad libitum until the age of 42 days. Treatments were replicated three times with 30 birds per replicate. Birds were fed with starter, grower and finisher diets. The feed consumed and body weights were recorded every week from the third to the sixth week. The average daily gain (ADG), average daily feed intake (ADFI) and the feed conversion ratio (FCR) were computed for each week. At Week 6, body weights of T3 birds were similar (P > 0.05) to those of T1 and T2 birds. There were also no treatment effects on the ADG at Week 6. In addition, no treatment effects (P > 0.05) were observed on ADFI at each stage of growth. Since ADFI and FCR were similar among the three groups, it was concluded that feed restriction by limiting the time to eat was not successful. There was also no evidence of compensatory growth in the restricted groups.     

Relationship between the activity of mitochondrial respiratory chain complexes and feed efficiency in fat-tailed Ghezel lambs

This study was conducted to investigate relationships between mitochondrial respiratory chain complex activities, feed efficiency, and carcass traits in sheep. A group of Ghezel male lambs sired by a single ram were randomly allotted to individual pens. The lambs were fed ad libitum with a fattening diet containing 30% roughage (corn silage and alfalfa hay) and 70% concentrate for 70 d to individually phenotype each lamb for feed conversion ratio (FCR), adjusted FCR (aFCR), and residual feed intake (RFI). The lambs were then humanely killed and the liver, abdominal fat, pelvic fat, cardiac fat, warm carcass weight, and cold carcass weight, as well as the cross-sectional area of the LM and the fat depth over the 12th rib, were determined. A portion of LM was obtained to determine mitochondrial protein and respiratory chain complex activities (complexes I to V). Statistical analysis was carried out based on lambs exhibiting high and low RFI (n = 8), FCR (n = 8), or aFCR (n = 8) phenotypes. The lambs exhibiting the high-RFI phenotype consumed 110 g more feed daily (P < 0.05) than did the phenotype exhibiting low RFI, with no difference in ADG. Conversely, there was no difference in feed intake between the low- or high-FCR groups, but sheep exhibiting the low-FCR phenotype gained 70 g more (P < 0.05) per day compared with those exhibiting the high-FCR phenotype. It was determined that all 5 respiratory chain complex activities were greater (P < 0.05) in sheep exhibiting the low-RFI phenotype compared with those exhibiting the high-RFI phenotype, with significant (P < 0.001) negative correlation coefficients between RFI and respiratory chain complex activity. When efficiency was assessed using FCR, only activities of respiratory chain complexes III, IV, and V were less (P < 0.05) in the low-FCR phenotype compared with the high-FCR phenotype, and there were no differences (P > 0.1) in respiratory chain complex activities between groups when FCR was adjusted for metabolic BW (aFCR). There were no differences (P > 0.1) in carcass traits among any of the feed efficiency phenotypes. The results suggest that the inclusion of respiratory chain complex activities in breeding programs may be helpful in selecting for sheep exhibiting the low-RFI phenotype.     

Evaluation of peripheral lymphocytes after weaning and vaccination for Mycoplasma hyopneumoniae

This study evaluated immune cell populations in pigs following weaning and vaccination for Mycoplasma hyopneumoniae. Piglets (n = 24) were weaned (day 0) at 16 (±1) days of age, and randomly assigned to the vaccination group (n = 16) or control group (n = 8). Complete blood cell counts, flow cytometry and serology were completed for blood samples collected on days 0 (within hours of weaning), 3, 7, 14, 30 and 60. The M. hyopneumoniae S:P ratios (sample optical density: positive control optical density) were negative in the vaccination group until days 30 and 60, when the S:P ratios were 1.3 and 1.0, respectively. Control animals remained serologically negative. The percentage of CD4⁺ T cells was less (P < 0.01) in control pigs than vaccinated pigs at day 3. In contrast, numbers of CD8⁺ and CD4⁺CD8⁺ T cells were greater (P < 0.01) in control pigs than in vaccinated pigs at days 3 and 7. After day 7, few differences in immune cell types were evident between the groups. Differences in lymphocyte populations could not be solely attributed to vaccination, due at least in part, to the confounding influence of weaning. It was difficult to distinguish the influence of vaccination from the impact of weaning on peripheral immune cell populations.     

Variance components due to direct genetic, maternal genetic and permanent environmental effect for growth and feed-efficiency traits in young male Japanese Black cattle

Variance components and genetic parameters were estimated using data recorded on 740 young male Japanese Black cattle during the period from 1971 to 2003. Traits studied were feed intake (FI), feed‐conversion ratio (FCR), residual feed intake (RFI), average daily gain (ADG), metabolic body weight (MWT) at the mid‐point of the test period and body weight (BWT) at the finish of the test (345 days). Data were analysed using three alternative animal models (direct, direct + maternal environmental, and direct + maternal genetic effects). Comparison of the log likelihood values has shown that the direct genetic effect was significant (p < 0.05) for all traits and that the maternal environmental effects were significant (p < 0.05) for MWT and BWT. The heritability estimates were 0.20 ± 0.12 for FI, 0.14 ± 0.10 for FCR, 0.33 ± 0.14 for RFI, 0.19 ± 0.12 for ADG, 0.30 ± 0.14 for MWT and 0.30 ± 0.13 for BWT. The maternal effects (maternal genetic and maternal environmental) were not important in feed‐efficiency traits. The genetic correlation between RFI and ADG was stronger than the corresponding correlation between FCR and ADG. These results provide evidence that RFI should be included for genetic improvement in feed efficiency in Japanese Black breeding programmes.     

The effect of monensin against swine dysentery

The use of monensin sodium against naturally transmitted swine dysentery was evaluated in 4-week-old piglets, with an average weight of 8 kg, over a period of 112 days. Three treatments were compared using between two and four pens per treatment and 12 pigs per pen. Monensin was administered via the feed, either immediately post weaning to four pens of pigs (T1), or after 12 days (T2, two pens). The T1 group received monensin at the rate of 100 ppm (days 0-56), 50 ppm (days 57-84) and 25 ppm until the end of the trial. In the other group monensin was given at 100 ppm (days 12-84) and at 50 ppm (days 85-112). Unmedicated feed was given to two pens (T3). The continuous administration of monensin from weaning was effective in the control or prevention of swine dysentery. A significant (P less than 0.05) improvement, in comparison with the other two groups, was observed in terms of mortality, diarrhoea score, average daily gain (ADG) and feed conversion ratio (FCR). There was a reduction in mortality, diarrhoea score/days and an improvement in growth performance parameters in pigs treated with monensin after the disease had been established, with ADG and FCR values significantly (P less than 0.05) different compared with the untreated controls.     

Estimating direct genetic and maternal effects affecting rabbit growth and feed efficiency with a factorial design

The aim of this experiment was to evaluate the significance of neonatal environment on feed efficiency. For that purpose, rabbits from a line selected for residual feed intake (RFI) during 10 generations (G10 kits) were cross‐fostered with non‐selected control does (i.e., G0 line), and reciprocally. In parallel, sibs were fostered by mothers from their original line. Nine hundred animals were raised in individual (N = 456) or collective (N = 320) cages. Traits analysed in this study were body weight at 32 days and at 63 days, average daily gain (ADG), feed intake between weaning and 63 days (FI), feed conversion ratio (FCR) and RFI. The maternal environment offered by does from the line selected for RFI deteriorated the FCR of the kits, independently of their line of origin, during fattening (+0.08 ± 0.02) compared to FCR of kits nursed by G0 does. The line, the type of housing and the batch were significant effects for all the measured traits: G10 kits were lighter than their G0 counterparts at 32 days (?82.9 ± 9 g, p < 0.0001) and at 63 days (?161 ± 16 g, p < 0.0001). They also had a lower ADG (?2.36 ± 0.36 g/day, p < 0.0001), RFI (?521 ± 24 g/day, p < 0.0001) and a lower FI (?855 ± 31 g, p < 0.0001), resulting in a more desirable feed efficiency (FCR: ?0.35 ± 0.02). There was no significant difference in the contrast of G10 and G0 performances between collective and individual/digestive cages (p > 0.22): ?2.35 g/day versus 2.94 g/day for ADG, ?0.39 versus ?0.40 for FCR, ?577 g versus ?565 g for RFI and ?879 g versus ?859 g for FI, respectively). Thus, no genotype‐by‐environment (housing) interaction is expected at the commercial level, that is, no re‐ranking of the animals due to collective housing.     

Field Study on the Efficacy of Two Different Vaccination Schedules with HYORESP® in a Mycoplasma hyopneumoniae‐Infected Commercial Pig Unit

A trial was carried out with HYORESP® a Mycoplasma hyopneumoniae (M. hyo) vaccine in order to confirm the benefit of vaccination under field conditions in a commercial industrial farrow‐ to‐finish unit, contaminated with M. hyo. Infection with M. hyo was confirmed through positive blood and colostrum samples [enzyme‐linked immunosorbent assay (ELISA) test] combined with positive gross lesions of the lung at slaughter. Two different vaccination schedules were tested. Pigs were randomly allocated to three groups: control non‐vaccinated group (n=130, given a placebo injection at 3, 25 and 70 days of age); early vaccinated group (n=128, given vaccination at 3 and 25 days of age and a placebo at 70 days of age); late vaccinated group (n=132, given a placebo at 3 and 25 days of age and vaccination at 70 days of age). Both growth rate and feed conversion ratio were significantly (P < 0.05) improved in the vaccinated groups compared with the control group. The lung lesion score was also significantly (P < 0.05) improved in both vaccinated groups. In this trial, it was clearly demonstrated that vaccination is highly effective in improving performance in pig units infected with M. hyo. The improvement in the feed conversion ratio in the vaccinated groups was especially impressive: – 0.411 (13% improvement) in the group vaccinated twice at 3 and 25 days of age; – 0.162 (5% improvement) in the group vaccinated once at 70 days of age. Performances were better when two shots were given early in life compared with one shot later – probably due to an infection taking place rather early in life for most of the pigs. Moreover, a significant reduction in the cost of supportive (injectable) medication was noticed in vaccinated pigs. In conclusion, HYORESP® proved to be a very efficacious tool to control M. hyo in infected herds with its remarkable flexibility that allows the vaccination schedule to be adapted to the specific field conditions.     

Genetic relationship of feed efficiency traits of bulls with growth and carcass traits of their progeny for Japanese Black (Wagyu) cattle

Genetic parameters for feed efficiency traits of 740 Wagyu bulls and growth and carcass traits of 591 of their progeny, and the genetic relationship between the traits of bulls and their progeny were estimated with the residual maximum likelihood procedure. The estimations were made for the test periods of 140 days (77 bulls), 112 days (663 bulls) and 364 days (591 steer progeny). Feed efficiency traits of bulls included feed conversion ratio (FCR), phenotypic residual feed intake (RFI_phe) and genetic residual feed intake (RFI_gen). Progeny traits were bodyweight at the start of the test (BWS), bodyweight at finish (BWF), average daily gain (ADG), rib eye area (REA), marbling score (MSR), dressing percentage (DRS) and subcutaneous fat thickness (SFT). The estimated heritability for MSR (0.52) was high and for BWS (0.35), BWF (0.40) and ADG (0.30) were moderate, whereas REA, DRS and SFT were low. Positive genetic correlations among BWS, BWF, ADG and SFT and negative genetic correlations between MSR and DRS and between REA and SFT were found. The genetic correlations between residual feed intake (RFI_phe and RFI_gen) of bulls and bodyweights (BWS and BWF) of their progeny ranged from ?0.27 to ?0.61. Residual feed intake was positively correlated with REA and DRS and negatively correlated with MSR and SFT. No responses in ADG and weakly correlated responses in REA and DRS of progeny were found to select against feed efficiency traits of bulls. The present experiment provides evidence that selection against lower RFI (higher feed efficiency) would be better than selection against lower FCR for getting better correlated responses in bodyweights.     

Different measures of energetic efficiency and their phenotypic relationships with growth, feed intake, and ultrasound and carcass merit in hybrid cattle

Residual feed intake (RFI) has been proposed as an index for determining beef cattle energetic efficiency. Although the relationship of RFI with feed conversion ratio (FCR) is well established, little is known about how RFI compares to other measures of efficiency. This study examined the phenotypic relationships among different measures of energetic efficiency with growth, feed intake, and ultrasound and carcass merit of hybrid cattle (n = 150). Dry matter intake, ME intake (MEI), ADG, metabolic weight (MWT), and FCR during the test averaged 10.29 kg/d (SD = 1.62), 1,185.45 kJ/(kg0.75 x d) (SD = 114.69), 1.42 kg/d (SD = 0.25), 86.67 kg0.75 (SD = 10.21), and 7.27 kg of DM/kg of gain (SD = 1.00), respectively. Residual feed intake averaged 0.00 kg/d and ranged from -2.25 kg/d (most efficient) to 2.61 kg/d (least efficient). Dry matter intake (r = 0.75), MEI (r = 0.83), and FCR (r = 0.62) were correlated with RFI (P < 0.001) and were higher for animals with high (>0.5 SD) RFI vs. those with medium (+/-0.5 SD) or low (<0.5 SD) RFI (P < 0.001). Partial efficiency of growth (PEG; energetic efficiency for ADG) was correlated with RFI (r = -0.89, P < 0.001) and was lower (P < 0.001) for high- vs. medium- or low-RFI animals. However, RFI was not related to ADG (r = -0.03), MWT (r = -0.02), relative growth rate (RGR; growth relative to instantaneous body size; r = -0.04), or Kleiber ratio (KR; ADG per unit of MWT; r = -0.004). Also, DMI was correlated (P < 0.01) with ADG (r = 0.66), MWT (r = 0.49), FCR (r = 0.49), PEG (r = -0.52), RGR (r = 0.18), and KR (r = 0.36). Additionally, FCR was correlated (P < 0.001) with ADG (r = -0.63), PEG (r = -0.83), RGR (r = -0.75), and KR (r = -0.73), but not with MWT (r = 0.07). Correlations of measures of efficiency with ultrasound or carcass traits generally were not different from zero except for correlations of RFI, FCR, and PEG, respectively, with backfat gain (r = 0.30, 0.20, and -0.30), ultrasound backfat (r = 0.19, 0.21, and -0.25), grade fat (r = 0.25, 0.19, and -0.27), lean meat yield (r = -0.22, -0.18, and 0.24), and yield grade (r = 0.28, 0.24, and -0.25). These phenotypic relationships indicate that, compared with other measures of energetic efficiency, RFI should have a greater potential to improve overall production efficiency and PEG above maintenance, and lead to minimal correlated changes in carcass merit without altering the growth and body size of different animals.     

Growth performance and intestinal morphology of Hyline chickens fed diets with different diet particle sizes

The effect of feed particle size on the growth performance and intestinal morphology of Hyline chickens was studied. Sixty one‐day‐old chickens were randomly assigned into two groups with five replicates per group and six chickens per replicate. The control group (CG) was fed pelleted feed and the experimental group (EG) was fed crumbled feed. The geometric mean diameter (GMD) of the pelleted and crumbled feed was approximately 1.2 and 0.8 mm respectively. The trial was carried out from day 15 to day 69 of the lives of the chickens. During the experimental period, the average daily feed intake (ADFI), average daily gain (ADG) and feed conversion rate ( FCR) were calculated. At 42 and 69 days of age, fifteen chickens from each group were slaughtered for the intestinal morphology analyses. The morphologies of various segments of the intestine were observed by scanning electron microscopy (SEM). The results showed that from 15 to 42 days of age, the FCR of the CG was higher than that of the EG, but the final body weight was lower in the CG than in the EG (p < 0.05). The villi heights in the duodenum, jejunum and ileum were shorter in the CG than in the EG (p < 0.05). The villi tips in the duodenum and jejunum of the CG were broken, but they were protected in the EG. At 69 days of age, the BW and the whole intestinal villi height of the CG were greater than those of the EG (p < 0.05). The villi in the duodenum and jejunum in the CG were better than 42 days, but the tips of the duodenal villi in the EG were slightly broken. In conclusion, feeding chickens crumbled feed from 15 to 42 days of age and then feeding them pelleted feed was beneficial to the growth performance of the Hyline chickens, as the pelleted feed would break the intestinal villi of young chickens, but the intestinal villi become stronger with the chicken growth.