A comparison between multivariate Slash, Student's t and probit threshold models for analysis of clinical mastitis in first lactation cows

Robust threshold models with multivariate Student's t or multivariate Slash link functions were employed to infer genetic parameters of clinical mastitis at different stages of lactation, with each cow defining a cluster of records. The robust fits were compared with that from a multivariate probit model via a pseudo‐Bayes factor and an analysis of residuals. Clinical mastitis records on 36 178 first‐lactation Norwegian Red cows from 5286 herds, daughters of 245 sires, were analysed. The opportunity for infection interval, going from 30 days pre‐calving to 300 days postpartum, was divided into four periods: (i) ?30 to 0 days pre‐calving; (ii) 1–30 days; (iii) 31–120 days; and (iv) 121–300 days of lactation. Within each period, absence or presence of clinical mastitis was scored as 0 or 1 respectively. Markov chain Monte Carlo methods were used to draw samples from posterior distributions of interest. Pseudo‐Bayes factors strongly favoured the multivariate Slash and Student's t models over the probit model. The posterior mean of the degrees of freedom parameter for the Slash model was 2.2, indicating heavy tails of the liability distribution. The posterior mean of the degrees of freedom for the Student's t model was 8.5, also pointing away from a normal liability for clinical mastitis. A residual was the observed phenotype (0 or 1) minus the posterior mean of the probability of mastitis. The Slash and Student's t models tended to have smaller residuals than the probit model in cows that contracted mastitis. Heritability of liability to clinical mastitis was 0.13–0.14 before calving, and ranged from 0.05 to 0.08 after calving in the robust models. Genetic correlations were between 0.50 and 0.73, suggesting that clinical mastitis resistance is not the same trait across periods, corroborating earlier findings with probit models.     

Performance and nutrient digestibility in growing pigs fed wheat dried distillers’ grain with solubles‐containing diets supplemented with phytase and multi‐carbohydrase

Effect of supplementing wheat dried distillers’ grain with solubles (DDGS)‐containing diet with enzymes on nutrient utilization by growing pigs was evaluated in two experiments. In Experiment 1, 60 pigs weighing ~30 kg were fed five diets that included a corn‐based diet (Control), Control with 10% wheat DDGS (DDGS‐PC), DDGS‐PC without inorganic P source (DDGS‐NC), and DDGS‐NC plus phytase alone or with multi‐carbohydrase for 4 weeks to determine average daily gain (ADG), average daily feed intake (ADFI) and gain‐to‐feed ratio (G:F). In Experiment 2, 30 barrows weighing 22 kg were fed five diets fed in Experiment 1 to determine nutrient digestibility and retention. Pigs fed DDGS‐PC and Control diets had similar ADG and G:F. The ADG and G:F for DDGS‐PC diet were higher (P < 0.05) than those for DDGS‐NC diet. Phytase improved (P < 0.05) ADG, G:F, total tract P digestibility and P retention by 6.6, 8.7, 86.0 and 85.5%, respectively. Addition of multi‐carbohydrase to phytase‐supplemented diet did not affected growth performance, but reduced (P < 0.05) P retention. In conclusion, inclusion of 10% wheat DDGS in growing pig diet may not affect growth performance of growing pigs. Phytase supplementation to wheat DDGS‐containing diet can eliminate the need for inorganic P supplement in pig diets.     

EFFECTS OF FLUID AND COMPUTED TOMOGRAPHIC TECHNICAL FACTORS ON CONSPICUITY OF CANINE AND FELINE NASAL TURBINATES

Turbinate destruction is an important diagnostic criterion in canine and feline nasal computed tomography (CT). However decreased turbinate visibility may also be caused by technical CT settings and nasal fluid. The purpose of this experimental, crossover study was to determine whether fluid reduces conspicuity of canine and feline nasal turbinates in CT and if so, whether CT settings can maximize conspicuity. Three canine and three feline cadaver heads were used. Nasal slabs were CT‐scanned before and after submerging them in a water bath; using sequential, helical, and ultrahigh resolution modes; with images in low, medium, and high frequency image reconstruction kernels; and with application of additional posterior fossa optimization and high contrast enhancing filters. Visible turbinate length was measured by a single observer using manual tracing. Nasal density heterogeneity was measured using the standard deviation (SD) of mean nasal density from a region of interest in each nasal cavity. Linear mixed‐effect models using the R package ‘nlme’, multivariable models and standard post hoc Tukey pair‐wise comparisons were performed to investigate the effect of several variables (nasal content, scanning mode, image reconstruction kernel, application of post reconstruction filters) on measured visible total turbinate length and SD of mean nasal density. All canine and feline water‐filled nasal slabs showed significantly decreased visibility of nasal turbinates (P < 0.001). High frequency kernels provided the best turbinate visibility and highest SD of aerated nasal slabs, whereas medium frequency kernels were optimal for water‐filled nasal slabs. Scanning mode and filter application had no effect on turbinate visibility.     

Nutritive value and non‐toxicity of Botryosphaeria zeae‐infected wheat for weaner pigs

A novel fungal infection of wheat by Botryosphaeria zeae was identified on the Darling Downs of Queensland, Australia and called ‘white grain’ because of its bleached appearance. The only nutritional changes in the wheat grain infected with B. zeae were decreases in nitrogen and total amino acids (～5%), and slight increases in the lysine, fibre and fat content, with starch unaffected. Nutrient digestibility and potential toxicity were assessed in weaner pigs housed in metabolism crates and fed this grain over a 4‐week period, as they grew from 15 to 35 kg. Digestibility of energy and nitrogen in white grain was not different from that of normal wheat. The piglets were then bled for biochemical and haematological testing, slaughtered and the entire viscera subjected to gross pathological inspection, followed by histological examination of the liver, kidney, pancreas, spleen, heart, lung, muscle and intestine. White grain did not affect palatability of diets, pig growth rates; no abnormalities were detected in tissues, while biochemical and haematological parameters did not suggest any toxic effect. Hence, wheat with white grain appears suitable for use in pig diets, but the use of this wheat for human food should be restricted until additional longer term studies are conducted.     

Genetic determination of mothering ability and piglet growth in indigenous Mukota sows of Zimbabwe

The objective of this study was to determine genetic parameters of individual and sow records on litter size and weights at 21 and 35 days in Mukota pigs. Data gathered from 1961 pigs at the University of Zimbabwe between January 1998 and August 2003, were analysed. Individual pig traits analysed were the weight at 21 days of age (THRWT), weight at weaning (WWT) and average daily gain from birth to weaning (ADGWW). Sow performance traits considered were the litter weight after 21 days (LTHRWT), litter weight at weaning (LWWT), number of pigs weaned (NW) and mothering ability (MA). An animal model was used to estimate genetic parameters using the average information restricted maximum likelihood procedure. Individual pig records were analysed using models with or without litter effects and maternal genetic effects. Incorporating the maternal genetic variance component drastically reduced the standard errors of the heritability estimates. The heritabilities for LTHRWT, LWWT and MA were 0.18, 0.15 and 0.05, respectively. The LWWT and NW were positively correlated. There were no genetic relationships between MA and LTHRWT and LWWT. No antagonisms should be expected when selecting for MA and increasing litter weights in Mukota pigs.     

Feeding value of whole raw soya beans as a protein supplement for beef cattle consuming low‐quality forages

Experiments (Exp) I and II were conducted to compare raw whole soya beans (WSB), roasted (rWSB) or other protein sources as supplements of low‐quality forages fed ad libitum to beef cattle, upon DM intake (DMI), ruminal and blood parameters, and animal performance. Exp I: treatments for wheat straw fed to four ruminally cannulated steers were (i) Control‐WS: no supplement; (ii) WSB‐WS: whole soya beans; (iii) rWSB‐WS: roasted WSB; and (iv) SBM‐WS: soybean meal–wheat midds mixture; all fed at 1.4 kg DM/day. Exp II: 12 steers grazed deferred grain sorghum (DS) receiving these treatments: (i) Control‐DS: no supplement; (ii) WSB‐DS: 1.26 kg DM/day whole soya beans; and (iii) SFM‐DS: 1.35 kg DM/day of sunflower meal. In Exp I, WS DMI resulted 47, 52 and 41% greater for WSB‐WS, rWSB‐WS and SBM‐WS, respectively, than Control‐WS (p < .05). In Exp II, the DMI of DS was unaffected by supplementation; a substitution of DS by supplement was found for WSB‐DS (p < .05); however, total diet and digestible DMI increased with supplementation (p < .05). Rumen pH in Exp I remained unaffected by supplementation, but N‐NH₃ as well as blood urea‐N in Exp II increased (p < .05). In Exp II, average daily weight gains improved similarly with both supplements compared with Control‐DS. Additionally, feed‐to‐gain ratio decreased (p < .05), being lower for WSB‐DS (8.3) vs. SFM‐DS (9.9). Roasting effects of WSB as a supplement for low‐quality forages were not detected, and all protein sources increased total diet DMI and forage utilization. Only moderate cattle weight gains could be expected for unsupplemented DS.     

The use of near infrared transmittance kernel sorting technology to salvage high quality grain from grain downgraded due to Fusarium damage

The mycotoxins associated with specific Fusarium fungal infections of grains are a threat to global food and feed security. These fungal infestations are referred to as Fusarium Head Blight(FHB) and lead to Fusarium Damaged Kernels(FDK). Incidence of FDK 0.25% will lower the grade, with a tolerance of 5%FDK for export feed grain. During infestation, the fungi can produce a variety of mycotoxins, the most common being deoxynivalenol(DON). Fusarium Damaged Kernels have been associated with reduced crude protein(CP), lowering nutritional, functional and grade value. New technology has been developed using Near Infrared Transmittance(NIT) spectra that estimate CP of individual kernels of wheat, barley and durum. Our objective is to evaluate the technology's capability to reduce FDK and DON of downgraded wheat and ability to salvage high quality safe kernels. In five FDK downgraded sources of wheat,the lowest 20% CP kernels had significantly increased FDK and DON with the high CP fractions having decreased FDK and DON, thousand kernel weights(TKW) and bushel weight(Bu). Strong positive correlations were observed between FDK and DON(r = 0.90); FDK and grade(r = 0.62) and DON and grade(r = 0.62). Negative correlations were observed between FDK and DON with CP(r =-0.27 and-0.32);TKW(r =-0.45 and-0.54) and Bu(r =-0.79 and-0.74). Results show improved quality and value of Fusarium downgraded grain using this technology.     

Use of robust multivariate linear mixed models for estimation of genetic parameters for carcass traits in beef cattle

Assumptions of normality of residuals for carcass evaluation may make inferences vulnerable to the presence of outliers, but heavy‐tail densities are viable alternatives to normal distributions and provide robustness against unusual or outlying observations when used to model the densities of residual effects. We compare estimates of genetic parameters by fitting multivariate Normal (MN) or heavy‐tail distributions (multivariate Student's t and multivariate Slash, MSt and MS) for residuals in data of hot carcass weight (HCW), longissimus muscle area (REA) and 12th to 13th rib fat (FAT) traits in beef cattle using 2475 records from 2007 to 2008 from a large commercial operation in Nebraska. Model comparisons using deviance information criteria (DIC) favoured MSt over MS and MN models, respectively. The posterior means (and 95% posterior probability intervals, PPI) of v for the MSt and MS models were 5.89 ± 0.90 (4.35, 7.86) and 2.04 ± 0.18 (1.70, 2.41), respectively. Smaller values of posterior densities of v for MSt and MS models confirm that the assumption of normally distributed residuals is not adequate for the analysis of the data set. Posterior mean (PM) and posterior median (PD) estimates of direct genetic variances were variable with MSt having the highest mean value followed by MS and MN, respectively. Posterior inferences on genetic variance were, however, comparable among the models for FAT. Posterior inference on additive heritabilities for HCW, REA and FAT using MN, MSt and MS models indicated similar and moderate heritability comparable with the literature. Posterior means of genetic correlations for carcass traits were variable but positive except for between REA and FAT, which showed an antagonistic relationship. We have demonstrated that genetic evaluation and selection strategies will be sensitive to the assumed model for residuals.     

Genetic relationship of litter traits between farrowing and weaning in Landrace and Large White pigs

We estimated genetic parameters in Landrace and Large White pig populations for litter traits at farrowing (total number born, number born alive, number stillborn, total litter weight at birth (LWB), and mean litter weight at birth) and those at weaning (litter size at weaning (LSW), total litter weight at weaning (LWW), mean litter weight at weaning (MWW), and survival rate from farrowing to weaning). We analyzed 65,579 records at farrowing and 6,306 at weaning for Landrace, and 52,557 and 5,360, respectively, for Large White. Single‐trait and two‐trait repeatability animal models were exploited to estimate heritability and genetic correlation respectively. Heritability estimates of LSW were 0.09 for Landrace and 0.08 for Large White. Genetic correlations of LSW with MWW were –0.43 for Landrace and –0.24 for Large White. Genetic correlations of LSW with LWW and LWB ranged from 0.5 to 0.6. The genetic correlation of MWW with LWW was positive, but that with LWB was negligible. The results indicate that utilizing LWW or LWB could improve LSW efficiently, despite the antagonistic genetic correlation between LSW and MWW.     

Genetic variation in litter size and kit survival of mink (Neovison vison)

The aims of this study are to estimate variance components of litter size and kit survival rate and estimate genetic correlations of litter size and kit survival rate with dam's juvenile body weight and pregnancy length. Variance components for litter size and kit survival were analysed using an AI-REML approach, based on data from 1940 litters of the black colour type mink from 1996 to 2001. The models included (i) additive genetic effect of dam; (ii) dam and sire genetic effects; (iii) additive genetic effect of dam in relation to litter size and dam and sire genetic effects in relation to survival rate; (iv) additive genetic effect of dam to estimate the correlations of litter size or kit survival with dam juvenile body weight and pregnancy length on yearling dams (1357 litters). The dam heritabilities were of litter size (0.02-0.08) and survival rate (0.05-0.10). The permanent effects of dam were important for litter size (0.15-0.19) but not for survival rate. A positive dam genetic correlation between litter size and survival rate was found at 1 week postpartum (0.42), and a positive sire genetic correlation between number of weaned kits and survival rate at the age of 6 month (0.72). Litter size and survival rate were genetically antagonistically related to dam's juvenile body weight (-0.34 to -0.53). These results indicate the following: (i) it is possible to improve litter size and kit survival by selection, (ii) effective improvement of kit survival rate in the suckling period requires selection for maternal effect on kit survival and kit's own capacity to survive and later in the growth period for kit's own ability to survive and (iii) antagonistic genetic correlation of dam juvenile body weight with litter size and survival rate should be taken into consideration in mink breeding programs.     

Effect of allele frequencies,effect sizes and number of markers on prediction of quantitative traits in chickens

The objective was to assess goodness of fit and predictive ability of subsets of single nucleotide polymorphism (SNP) markers constructed based on minor allele frequency (MAF), effect sizes and varying marker density. Target traits were body weight (BW), ultrasound measurement of breast muscle (BM) and hen house egg production (HHP) in broiler chickens. We used a 600 K Affymetrix platform with 1352 birds genotyped. The prediction method was genomic best linear unbiased prediction (GBLUP) with 354 564 single nucleotide polymorphisms (SNPs) used to derive a genomic relationship matrix ( G ). Predictive ability was assessed as the correlation between predicted genomic values and corrected phenotypes from a threefold cross‐validation. Predictive ability was 0.27 ± 0.002 for BW, 0.33 ± 0.001 for BM and 0.20 ± 0.002 for HHP. For the three traits studied, predictive ability decreased when SNPs with a higher MAF were used to construct G . Selection of the 20% SNPs with the largest absolute effect sizes induced a predictive ability equal to that from fitting all markers together. When density of markers increased from 5 K to 20 K, predictive ability enhanced slightly. These results provide evidence that designing a low‐density chip using low‐frequency markers with large effect sizes may be useful for commercial usage.     

Analysis of litter size and days to lambing in the Ripollesa ewe. I. Comparison of models with linear and threshold approaches

The analysis focused on model fitting of 2 ewe reproductive traits, litter size, and days to lambing (interval between the introduction of the ram into the flock and the subsequent parturition of the ewes). The experimental data set of the Universitat Autònoma of Barcelona flock was used, including 1,598 records of litter size and 1,699 records of days to lambing from 376 Ripollesa ewes between 1986 and 2005. Univariate and bivariate models were considered as beginning points with linear or threshold approximation for litter size. Model fitting was evaluated in terms of goodness-of-fit and predictive ability, using the mean square error and the correlation between phenotypic and predicted records (rho(y,?)) as reference parameters. The bivariate model was preferable for both variables, minimizing mean square error and maximizing rho(y,?). A threshold approximation for litter size was preferable over a linear approximation. Models were also compared with a simulation study, comparing the correlation coefficient between simulated and predicted breeding values (rho(a,a)). The bivariate threshold model was favored, with a rho(y,?) of 0.677 and 0.834 for litter size and days to lambing, respectively. Correlation coefficients between simulated and predicted breeding values in the bivariate linear model were reduced slightly to 0.651 and 0.831, respectively, and they were lowest with linear univariate models (0.642 and 0.802). Although the bivariate models for ewe litter size and days to lambing were more accurate than the univariate models, the threshold approaches showed a greater advantage under the bivariate model. For the purpose of genetic evaluation of litter size in sheep, use of the threshold-linear model seems justified. In the Ripollesa breed, the evaluation of litter size can benefit from recording birth weight.     

Improving the Quality of Miniature Pig Somatic Cell Nuclear Transfer Blastocysts: Aggregation of SCNT Embryos at the Four‐cell Stage

Miniature pigs share many similar characteristics such as anatomy, physiology and body size with humans and are expected to become important animal models for therapeutic cloning using embryonic stem cells (ESCs) derived by somatic cell nuclear transfer (SCNT). In the present study, we observed that miniature pig SCNT blastocysts possessed a lower total number of nuclei and a lower percentage of POU5F1‐positive cells than those possessed by in vitro fertilized (IVF) blastocysts. To overcome these problems, we evaluated the applicability of aggregating miniature pig SCNT embryos at the four‐cell stage. We showed that (i) aggregation of two or three miniature pig SCNT embryos at the four‐cell stage improves the total number of nuclei and the percentage of POU5F1‐positive cells in blastocysts, and (ii) IVF blastocysts with low cell numbers induced by the removal of two blastomeres at the four‐cell stage did not exhibit a decrease in the percentage of POU5F1‐positive cells. These results suggest that the aggregation of miniature pig SCNT embryos at the four‐cell stage can be a useful technique for improving the quality of miniature pig SCNT blastocysts and indicating that improvement in the percentage of POU5F1‐positive cells in aggregated SCNT embryos is not simply the consequence of increased cell numbers.     

An acute reversible experimental model of pneumonia in pigs: time‐related histological and clinical signs changes

The objective of this study was to evaluate the long‐term survival rates, clinical response, and lung gross and microscopic changes in pigs treated intratracheally with lipopolysaccharide of Escherichia coli 0111:B4 (LPS‐Ec). Healthy pigs were randomly allocated to three groups: (i) no‐LPS‐Ec (n = 1), (ii) LPS‐Ec‐T1 (1 mg/mL, 10 mL/pig) (n = 7), and (iii) LPS‐Ec‐T2 (0.5 mg/mL, 10 mL/pig) (n = 6). Two pigs from each dose group were euthanized at 24 (n = 3 for T1), 48 and 144 h post‐LPS‐Ec challenge. LPS‐Ec‐treated animals showed macroscopic lesions in middle lobes of the lung. A reversible recruitment of macrophages and neutrophils was observed at 24, 48, and 144 h post‐LPS‐Ec challenge. The highest cellular infiltration level was observed at 24 h after challenge. The highest clinical scores were evident in both experimental dose levels within 3 and 5 h after LPS‐Ec administration. Administration of LPS‐Ec, under the conditions evaluated, can be used to induce a reproducible model of acute pulmonary inflammation in pigs.     

Effect of Porcine and Ovine FSH on Nuclear Maturation of Pig Oocytes In Vitro

The effect of porcine or ovine FSH on the maturation rate of porcine oocytes and on the time course of meiotic progression was studied. Groups of 20 grade‐A cumulus oocyte complexes, aspirated from slaughterhouse cycling‐gilt ovaries, were cultured in vitro in 400 μl of Modified Parker's Medium supplemented with oestrous cow serum and porcine FSH (Folltropin®‐V, 0.50 mg/ml) or ovine FSH (Ovagen^TM, 0.44 iu/ml), in four‐well dishes under mineral oil, at 38.5°C, 5% CO₂ in humidified air. At the end of each 3‐h interval, from 3 to 42 h of culture, the nuclear status of oocytes was assessed microscopically (1000×), after fixation (methanol/acetic acid: 3/1) and orcein (2%) staining. Oocytes were classified as (i) immature (IMM), i.e. oocytes at germinal vesicle stage, germinal vesicle break down and prophase I, (ii) metaphase I (MI) and (iii) metaphase II (MII), i.e. oocytes at anaphase I, telophase I and metaphase II. Data were analysed using regression analysis, chi‐square and t‐test. Nuclear status was assessed in 1610 oocytes (porcine FSH: 787, ovine FSH: 823). Most of the oocytes were at MI from 24 to 33 h (porcine FSH 60.27%, ovine FSH 42.80%, p < 0.001) and at MII from 36 to 42 h (porcine FSH 80.38%, ovine FSH 67.45%, p < 0.01) of culture. Significantly higher maturation rate was observed in porcine FSH than in ovine FSH treated oocytes (86.69 ± 12.97%, 71.34 ± 9.86%, mean ± SD, p < 0.05), after 42 h of culture. In conclusion, under the specific culture conditions, porcine FSH seems to support pig oocyte maturation better than ovine FSH.     

Ultrasound during mid‐gestation: Agreement with physical foetal and placental measurements and use in predicting gestational age in sheep

To determine the effects of poor maternal nutrition and litter size on foetal growth during mid‐gestation, pregnant ewes (n = 82) were fed 100%, 60% or 140% of NRC TDN beginning at day 30.2 ± 0.2 of gestation. Transabdominal ultrasound was performed weekly between day 46.0 ± 0.4 and 86.0 ± 0.7 to monitor foetal heart width (HW), umbilical diameter (UMB), rib width (RW) and placentome outer (OD) and inner diameter (ID). Data were analysed with repeated‐measures using the mixed procedure for effects of maternal diet, litter size and gestation, and equations predictive of gestational age were generated using the regression procedure. To determine the agreement of ultrasound measurement and actual size, ewes (n = 20–21) were euthanized at day 45 or 90 to obtain corresponding postmortem measurements for Bland–Altman analysis. The HW, UMB and placentome OD and ID increased with gestation (p < .0001) but were unaffected by maternal diet or litter size (p ≥ .12). Ultrasound underestimated postmortem measurements of HW (14.8%), UMB (7.3%), placentome OD (4.5%) and ID (37.3%) at day 90 of gestation. Ultrasound underestimated RW at day 45 (7.7%) but overestimated RW (23.8%) at day 90, indicating inconsistent bias when reporting RW by ultrasound. Combining the HW, UMB, RW and placentome OD generated the strongest equation predictive of gestational age (R² = .91). These findings indicate that during mid‐gestation, maternal diet or litter size did not affect HW, UMB or placentome diameters and these factors can be used to estimate gestational age.     

胎次对母猪产仔性能的影响

根据福建某种猪场的生产记录,应用SPSS软件对不同胎次的3588窝大白、长白和杜洛克纯种母猪的窝产仔数、窝产活仔数等进行统计分析。结果表明,在大白、长白和杜洛克纯种母猪中,胎次对窝产仔数和窝产活仔数的影响极显著(P<0.01),平均窝产仔数、窝产活仔数最高均为第6胎,分别为11.44和10.26头,最少均为第1胎,分别为9.49头和8.56头。     

Genetic analysis of the rates of conception using a longitudinal threshold model with random regression in dairy crossbreeding within a tropical environment

This study was designed to: (i) estimate genetic parameters and breeding values for conception rates (CR) using the repeatability threshold model (RP‐THM) and random regression threshold models (RR‐THM); and (ii) compare covariance functions for modeling the additive genetic (AG) and permanent environmental (PE) effects in the RR‐THM. The CR was defined as the outcome of an insemination. A data set of 130 592 first‐lactation insemination records of 55 789 Thai dairy cows, calving between 1996 and 2011, was used in the analyses. All models included fixed effects of year × month of insemination, breed × day in milk to insemination class and age at calving. The random effects consisted of herd × year interaction, service sire, PE, AG and residual. Variance components were estimated using a Bayesian method via Gibbs sampling. Heritability estimates of CR ranged from 0.032 to 0.067, 0.037 to 0.165 and 0.045 to 0.218 for RR‐THM with the second, third and fourth‐order of Legendre polynomials, respectively. The heritability estimated from RP‐THM was 0.056. Model comparisons based on goodness of fit, predictive abilities, predicted service results of animal, and pattern of genetic parameter estimates, indicated that the model which fit the desired outcome of insemination was the RR‐THM with two regression coefficients.     

Feeding value for finishing beef steers of wheat grain conserved by different techniques

The objective was to determine the feeding value of high moisture grain as an alternative to dry grain for finishing beef cattle. Winter wheat grain was harvested sequentially for rolling, acid treatment and ensilage (ER; 705 g dry matter (DM)/kg), urea whole grain treatment and anaerobic storage (UN; 746 g DM/kg) and whole grain propionic acid treatment and aerobic storage (rolled before feeding; PR; 849 g DM/kg). Friesian steers (n = 120; mean starting live-weight 518 kg) were allocated on a live-weight basis to 12 replicate blocks and then randomly assigned from within blocks to ten treatments. Treatments were grass silage offered ad libitum together with (i) no wheat, (ii–iv) PR at 3 or 6 kg/head daily, or ad libitum, (v–vii) UN at equivalent DM allowances to (ii) and (iii) above, or ad libitum, (viii–x) ER at equivalent DM allowances to (ii) and (iii) above, or ad libitum. Mean daily live-weight gains were 852 (ER), 726 (UN) and 855 g (PR) (s.e. = 65.5; P < 0.05) with corresponding values for carcass gain of 522, 425 and 528 g (s.e. = 35.6; P < 0.001) and daily silage DM intakes of 3.5, 4.0 and 3.6 kg (s.e. = 0.15; P < 0.001). Wheat DM intake when offered ad libitum was 7.8, 8.3 and 8.2 kg (s.e. = 0.10; P < 0.05) for ER, UN and PR, respectively. The content of apparently undigested whole grains and starch in faeces was higher (P < 0.001) for UN than for ER and PR, particularly at higher rates of wheat ingestion. It is concluded that ER treatment of wheat grain can be an acceptable alternative to the more traditional PR and superior to the UN treatment in the diets of finishing beef cattle.