母猪乳头数及哺乳位置等对哺乳仔猪早期日增重的影响

为了解母猪乳头数、仔猪哺乳位置(前、中、后)、性别和初生重等因素对哺乳仔猪早期日增重的影响,本研究选取了预产期、胎次相近的沙乌头、杜×沙、长×大母猪各5头以及它们产后的哺乳仔猪,记录母猪左右两侧乳头数并将乳头分为前、中、后区。同时记录仔猪哺乳位置,初生重(1日龄)、3日龄、6日龄、9日龄体重。结果表明:不同品种或杂交组合母猪乳头数有显著差异;不同性别仔猪初生重无显著差异,性别对仔猪1~9日龄日增重的影响也不显著;不同哺乳位置间仔猪初生重无显著差异,但仔猪日增重与其初生重显著相关;哺乳位置对沙乌头母猪所产仔猪1~9日龄日增重影响不显著,但是对杜沙和长大母猪所产仔猪3-9日龄日增重有显著影响。     

Factors associated with average daily gain, fever and lameness in beef bulls at the Saskatchewan Central Feed Test Station.

Data obtained from the Saskatchewan Central Feed Test Station in Saskatoon, Saskatchewan, Canada were examined for evidence of factors related to average daily gain and the diseases occurring in 326 beef bulls during the 1983-84 test. Average daily gain was found to be significantly associated with breed, pen assignment and initial test weight but was not associated with disease or age upon arrival at the test station. Lameness was associated with breed and initial weight, while fever (suspected respiratory disease) was associated with age. The predicted odds of lameness was approximately seven times greater in the animal with the heaviest as compared to the lightest initial test weight and the predicted odds of fever was approximately five times greater in the youngest as compared to the oldest animal.     

Estimation of genetic parameters for average daily gain using models with competition effects

Components of variance for ADG with models including competition effects were estimated from data provided by the Pig Improvement Company on 11,235 pigs from 4 selected lines of swine. Fifteen pigs with average age of 71 d were randomly assigned to a pen by line and sex and taken off test after approximately 89 d (off-test BW ranged from 61 to 158 kg). Models included fixed effects of line, sex, and contemporary group and initial test age as a covariate, with random direct genetic, competition (genetic and environmental), pen, litter, and residual effects. With the full model, variances attributable to direct, direct-competition, genetic competition, and litter (co)variance components could be partitioned; genetic competition variance was small but statistically significantly different from zero. Variances attributable to environmental competition, pen, and residual effects could not be partitioned, but combinations of these environmental variances were estimable. Variances could be partitioned with either pen effects or environmental competition effects in the model. Environmental competition effects seemed to be the source of variance associated with pens. With pen as a fixed effect and without environmental competition effects in the model, genetic components of variance could not be partitioned, but combinations of genetic (co)variances were estimable. With both pen and environmental competition effects ignored, estimates of direct-competition and genetic competition (co)variance components were greatly inflated. With competition (genetic and environmental) effects ignored, the estimate of pen variance increased by 39%, with little change in estimates of direct genetic or residual variance. When both pen and competition (genetic and environmental) effects were dropped from the model, variance attributable to direct genetic effects was inflated. Estimates of variance attributable to competition effects were small in this study. Including environmental competition effects as permanent environmental effects in the model did not change estimates of genetic (co)variances. We concluded that including either pen effects or environmental competition effects as random effects in the model avoids bias in estimates of genetic variances but that including pen effects is much easier.     

浅谈哺乳仔猪的培育措施

由于仔猪有许多和成年猪、生长猪生理特点上的不同之处,所以不能用饲养成年猪的方法饲养仔猪.从猪场经营的角度看,仔猪培育的好坏直接关系到猪场的经济效益.从个体发育角度看,仔猪阶段的生长性能对以后的生产性能有很大的影响.因此,在哺乳仔猪阶段要从以下6个方面加以注意并采取措施,以保证仔猪的健康生长和快速增重.     

Association between lean meat percentage and average daily weight gain in Danish slaughter pigs

Danish pigs that are within optimal weight limits and have a high lean meat percentage (LMP) obtain the best prices at slaughter. Another reason to consider the variation in LMP is the assumed association between LMP and average daily weight gain (ADG) at the individual level. The aim of this study was to test whether high ADG was associated with low LMP and vice versa. A cohort of 99 pigs from a conventional Danish herd was followed from 30kg to slaughter. The data included days in the herd, start- and end-weights, calculated ADG and LMP, reported from the abattoir. The study also included existing data from 13,057 boars from a Danish boar test station. The results of the study demonstrated a significant negative association between LMP and ADG: Pearson's correlation coefficient (r)=-0.42 (95% CI: -0.57; -0.24) (p<0.0001) for the cohort and r=-0.42 (95% CI: -0.48; -0.36) (p<0.0001) for the boars.     

Effects of animal and supplement characteristics on average daily gain of grazing beef cattle

Effects of animal gender and age, use of a growth stimulant, and supplementation with grain alone or grain plus other substances on ADG by growing beef cattle grazing bermudagrass paddocks with sod-seeded rye, wheat, and ryegrass were determined. Two grazing experiments (Exp. 1: late winter through mid-spring; Exp. 2: late spring through mid-summer) were conducted. Experiment 1 used 96, 12- to 13-mo-old Simmental-cross calves (heifers, 240 kg; steers, 272 kg), half of which were implanted with zeranol. Within each implant treatment, cattle received no supplement or .5% BW (DM) of ground corn alone or plus a mix of protein meals, zinc sulfate, thiamin-HCl, or salt. Daily gain was higher (P less than .05) with than without supplementation and was similar (P greater than .10) among supplement treatments. In Exp. 2, 96 crossbred beef steers, approximately 7 (230 kg) or 15 mo old (250 kg), were not supplemented (control) or received .5% BW (DM) of ground corn on d 1 to 84 (C-C), corn plus a protein meal mix on d 1 to 84 (CP-CP), corn on d 43 to 84 (O-C), corn plus the protein meal mix on d 43 to 84 (O-CP), or corn on d 1 to 42 and corn plus the protein meal mix on d 43 to 84 (C-CP). Daily gain on d 1 to 84 was affected (P less than .05) by supplement, age, implant, and the supplement x implant interaction (nonimplanted: .37, .56, .68, .40, .49, and .49; implanted: .37, .62, .54, .49, .70, and .71 kg for control, C-C, CP-CP, O-C, O-CP, and C-CP, respectively).     

Effects of social interactions on empirical responses to selection for average daily gain of boars

Effects of social interactions on responses to selection for ADG were examined with records of 9,720 boars from dam lines (1 and 2) and sire lines (3 and 4) provided by Pig Improvement Company. Each line was analyzed separately. Pens contained 15 boars. Average daily gains were measured from about 71 to 161 d of age and BW from 31 to 120 kg. Models included fixed effects of contemporary groups and initial test age as a covariate and random direct genetic (a), social genetic (c), social environmental (ce), and litter (lt) effects. Estimates of direct heritability with model 1 (the full model with a, c, ce, and lt) were 0.21, 0.28, 0.13, and 0.15 for lines 1 to 4. Estimates of heritability of social effects were near zero. Estimates of total heritable variance were 55, 52, 38, and 96% of phenotypic variance for lines 1 through 4. Empirical responses to selection with model 1 were calculated using the parameter estimates from model 1. For response of 1 genetic SD for both components (a and c), the proportions of expected total gain due to social effects (with economic weights of 1 and pen size-1 = 14) were 54, 28, 65, and 65% for the 4 lines. Genetic superiorities of the top 10% of boars were calculated for boars ranked using reduced models, but with EBV calculated using the full model (model 1). Average total breeding values (ETBV = EBV(a)+14EBV(c)) for the top 10% of boars selected with model 1 were 74.08, 94.26, 31.79, and 92.88 g for lines 1 through 4, respectively. For rankings based on model 2 (a, ce, and lt), but EBV calculated with model 1, average total breeding values for the top 10% were 68.15, 94.03, 7.33, and 84.72 g with empirical correlated responses for genetic social effects from selection for direct effects of 0.93, 1.89, -2.19, and 3.52 g for lines 1 to 4.     

Quantifying the effect of inbreeding on average daily gain and Kleiber ratio in Mazandaran native chickens

Tropical Animal Health and Production - The aims of this study was to evaluate inbreeding effects for growth rate (average daily gain from hatch to 8&nbsp;weeks of age (ADG1–8), average...     

Utilization of milk amino acids by the suckling Iberian piglet

Sixteen pure-bred Iberian (IB) sows were used in two trials to determine the efficiency of utilization of milk protein and amino acid (AA) for growth in suckling piglets. It was hypothesized that there may be one or more strongly limiting essential AA (EAA) responsible for the slow rate of growth of the IB piglet. This AA will show the highest fractional retention. Daily milk yield and composition were determined weekly over a 34-day lactation period. Within each litter, one piglet at birth and four piglets on d 35 of life were slaughtered. The protein content of the IB sow milk was similar to that reported for conventional breeds. However, branched-chain AA, Thr, Pro, Asp and Ala were in concentrations somewhat below the range of literature values and Arg and Met, substantially above it. Milk intake per piglet tended to be greater in Trial 2 (832 vs. 893 g/day respectively; p = 0.066). However, the IB piglets grew at 168 ± 3.3 g/day, irrespective of the trial. The whole-body protein of piglets at weaning and the protein deposited in their body during the lactating period showed very close AA pattern. Among EAA, His and Arg show the highest fractional retentions (g AA retained/g AA ingested) in whole-body tissues (1.019 ± 0.025 and 0.913 ± 0.017 respectively) and also the highest body to milk ratios (1.50 and 1.41 respectively). Gly and Ala presented, among non essential AA, the highest efficiencies of utilization for tissue deposition (1.803 ± 0.057 and 1.375 ± 0.026 respectively) and body to milk ratios (2.75 and 2.12 respectively). These results suggest that the low efficiency of utilization of milk protein and the low rate of gain of the IB suckling piglet can be explained by a marked shortage in His supply, in addition to the suboptimal milk provision of Arg, Gly and Ala.     

The effects of spaying and anabolic implants on the average daily weight gain of heifers on pasture

Two studies were carried out to determine the effects of spaying and implanting on the growth of heifers and compare Ralgro and Synovex-S for spayed heifers. In the first study, 121 crossbred heifers were randomly allocated to four groups: intact and no implant; intact and progesterone and estradiol benzoate (Synovex-S); spayed and no implant; and spayed and Synovex-S. The average daily gain (ADG) and body weight (BW) data were analyzed as a 2 × 2 factorial experiment with a pasture effect which was considered as a block. Based on ADG for days 0-120, the response to implanting was 17.6% for spayed heifers and 1.8% for intact heifers. In the second study, 31 spayed heifers implanted with zeranol (Ralgro) were compared with 30 spayed heifers implanted with Synovex-S. The data were analyzed as a one-way analysis of variance. The ADG for spayed heifers on Ralgro did not differ significantly (p>0.05) from those implanted with Synovex-S over a period of 92 days, suggesting that both implants produce similar growth responses.     

Association between average daily gain,faecal dry matter content and concentration of Lawsonia intracellularis in faeces

Background

The objective of this study was to investigate the association between average daily gain and the number of Lawsonia intracellularis bacteria in faeces of growing pigs with different levels of diarrhoea.

Methods

A longitudinal field study (n = 150 pigs) was performed in a Danish herd from day 29 to 47 post weaning. Every third day all pigs were weighed, subjected to a clinical examination and faecal samples were obtained. Faecal samples were subjected to dry matter determination and absolute quantification by PCR for L. intracellularis and porcine circovirus type 2 (PCV2). Association between average daily gain, faecal dry matter content, numbers of L. intracellularis bacteria and PCV2 genome copies in faeces was investigated in a multilevel mixed-effects linear model.

Results

Increasing numbers of L. intracellularis log₁₀ bacteria/g faeces were significantly associated with decreasing average daily gain (P < 0.001). The association was decreasing with increasing faecal dry matter content (P < 0.01). The number of PCV2 log₁₀ copies/g faeces was not significantly associated with average daily gain of the pigs (P > 0.5).

Conclusion

The results suggest a potential application of a PCR quantifying L. intracellularis in growing pigs. Faecal dry matter content must be taken into consideration in interpretation of such test results.     

Feed conversion ratio,residual feed intake and cholecystokinin type A receptor gene polymorphisms are associated with feed intake and average daily gain in a Chinese local chicken population

Background: The feed conversion ratio(FCR) and residual feed intake(RFI) are common indexes in measuring feed efficiency for livestock. RFI is a feed intake adjusted for requirements for maintenance and production so these two traits are related. Similarly, FCR is related to feed intake and weight gain because it is their ratio. Cholecystokinin type A receptor(CCKAR) plays an important role in animal digestive process. We examined the interplay of these three parameters in a local Chinese chicken population.Results: The feed intake(FI) and body weights(BW) of 1,841 individuals were monitored on a daily basis from 56 to 105 d of age. There was a strong correlation between RFI and average daily feed intake(ADFI) and a negative correlation between the FCR and daily gain(r_g=-0.710). Furthermore, we identified 51 single nucleotide polymorphisms(SNPs) in the CCKAR and 4 of these resulted in amino acid mutations. The C334A mutation was specifically associated with FI and the expected feed intake(EFI)(P 0.01) and significantly associated with the average daily gain(ADG)(P 0.05). G1290A was significantly associated with FI and EFI(P 0.05).Conclusion: FCR is apply to weight selecting, and RFI is more appropriate if the breeding focus is feed intake. And C334A and G1290A of the CCKAR gene can be deemed as candidate markers for feed intake and weight gain.     

Genome‐wide association study for feedlot average daily gain in Nellore cattle (Bos indicus)

The genome‐wide association study (GWAS) results are presented for average daily gain (ADG) in Nellore cattle. Phenotype of 720 male Bos indicus animals with information of ADG in feedlots and 354 147 single‐nucleotide polymorphisms (SNPs) obtained from a database added by information from Illumina Bovine HD (777 962 SNPs) and Illumina BovineSNP50 (54 609) by imputation were used. After quality control and imputation, 290 620 SNPs remained in the association analysis, using R package Genome‐wide Rapid Association using Mixed Model and Regression method GRAMMAR‐Gamma. A genomic region with six significant SNPs, at Bonferroni‐corrected significance, was found on chromosome 3. The most significant SNP (rs42518459, BTA3: 85849977, p = 9.49 × 10^?8) explained 5.62% of the phenotypic variance and had the allele substitution effect of ?0.269 kg/day. Important genes such as PDE4B, LEPR, CYP2J2 and FGGY are located near this region, which is overlapped by 12 quantitative trait locus (QTLs) described for several production traits. Other regions with markers with suggestive effects were identified in BTA6 and BTA10. This study showed regions with major effects on ADG in Bos indicus in feedlots. This information may be useful to increase the efficiency of selecting this trait and to understand the physiological processes involved in its regulation.     

Effect of monensin and tylosin on average daily gain, feed efficiency and liver abscess incidence in feedlot cattle

Fourteen trials were conducted to evaluate the effects of feeding monensin at 33 ppm alone, tylosin at 11 ppm alone and the two feed additives in combination on the average daily gain, average daily feed intake, feed:gain ratio and the incidence of liver abscesses in feedlot cattle. Monensin reduced feed intake and improved feed efficiency (P less than .05), and had no effect on average daily gain. Tylosin improved average daily gain (P less than .05) and had no effect on daily feed intake. The effect of tylosin on feed efficiency approached significance. The interaction of monensin and tylosin was nonsignificant for daily gain, daily feed intake and feed:gain ratio. Monensin had no effect on liver abscess incidence, while tylosin reduced abscess incidence from 27 to 9%.     

浅谈规模养猪场哺乳仔猪腹泻的原因及其控制

目前,规模化的养猪场、养殖大户在实际生产中,经常发生由环境中不良因素诱发引起的仔猪条件性腹泻,危害相当严重,不仅给养猪业带来直接的经济损失,还间接影响到病猪愈后的生长发育,成为影响提高养猪业经济效益的重要因素.     

Estimates of covariance components and genetic parameters for growth,average daily gain and Kleiber ratio in Harnali sheep

Tropical Animal Health and Production - The aim of the present study was to estimate the (co)variance components and genetic parameters for various growth traits (weight at birth (BWT) and 3 (WT3),...     

Breed means for average daily gain, feed conversion and intake of beef bulls during postweaning feedlot performance tests

Comparisons of ADG, feed/gain, daily feed intake and daily feed intake as percentage of body weight may be important to beef cattle producers and researchers in breed selection and computer modeling. Data evaluated were postweaning feedlot performance test records collected from 1967 to 1986 of 3,661 individually fed bulls. Bulls originated from University of Arkansas purebred herds, Fayetteville, and the University of Arkansas Cooperative Bull Tests at Fayetteville, Hope and Monticello. Data were analyzed separately for years 1967 to 1976 (P1) (n = 1,654) and 1977 to 1986 (P2) (n = 2,007). Breeds in P1 were Hereford (HH), Angus (AN), Charolais (CH), Polled Hereford (HP) and Santa Gertrudis (SG). Breeds in P2 were HH, AN, CH, HP, SG, Simmental (SM), Maine-Anjou (MA), Brangus (BN) and Beefmaster (BM). The model fitted included initial age, breed and test number (all P less than .01 except for initial age on ADG in P1). Test number included variation of year, location and season. Breed rankings from highest to lowest for ADG in P1 were CH, SG, HH, HP and AN and in P2 were MA, CH, SM, AN, HP, SG, HH, BN and BM. Breed rankings from highest to lowest for feed/gain in P1 were AN, SG, CH, HP and HH and in P2 were BM, BN, AN, SG, HP, SM, HH, MA and CH. Breeds highest to lowest for daily feed intake (as-fed basis) in P1 were CH, SG, AN, HP and HH and in P2 were SM, MA, CH, AN, BN, HP, SG, HH and BM.(ABSTRACT TRUNCATED AT 250 WORDS)