Effects of milk replacer and starter diet provided as creep feed for suckling pigs on pre‐ and post‐weaning growth

This study was aimed at investigating the long‐term effects of provision of liquid milk replacer (MR) and solid starter diet (SD) during lactation on post‐weaning (PW) growth of pigs. In experiment 1, 33 cross‐bred litters were allotted to four treatments: no supplement (CON), MR ad libitum, SD ad libitum and 100 g SD/litter/day from lactation day 4 through weaning at day 21 during late fall. In experiment 2, 40 litters received MR or none in July. PW pigs received commercial diets to marketing. In experiment 1, weaning weight (WW), pre‐weaning average daily gain (ADG) and mortality (2.4%) were not influenced by creep‐feeding MR or SD. ADG was greater (P < 0.05) in the MR group versus CON during days 21–54, but did not differ across the treatments during days 54–162. In experiment 2, ADG during lactation and WW were greater in the MR group versus CON, with mortality lower in the former (5.6 vs. 10.3%). However, PW ADG to day 175 did not differ between the two groups. Results suggest that creep‐feeding MR or SD has no effect on PW growth. However, it remains possible that MR reduces PW mortality during the hot season.     

Effect of probiotics on blood fatty acid metabolism during the late middle stage of fattening period in Japanese Black cattle

This study was conducted to investigate the effects of probiotics administration on fatty acid metabolism in Japanese Black cattle as per changes in blood fatty acid concentrations and blood biochemical tests. Eighteen clinically healthy Japanese Black female fattening cattle bred on the same fattening farm were randomly classified into the probiotics administration group (n=9) or the control group (n=9). In the probiotics administration group, 50 g of probiotics were started per animal per day at the age of 18 months, and the administration period was 2 months from the start date of the study. Blood was collected twice before starting the probiotics administration and at 2 months after starting the probiotics administration. In the probiotics administration group, palmitic, linoleic, arachidonic and α-linolenic acid tended to be higher at the end of the administration compared with those before probiotics administration. Additionally, as a result of multiple comparison test, monounsaturated fatty acids at Post was significantly higher, and the ω6 / ω3 ratio was significantly lower than in the control group. Vitamin A, E and albumin were significantly higher at the end of the administration than in the control group. In this study that administering probiotics to Japanese Black cattle in the late middle stage of fattening period did not have a significant effect on fatty acid metabolism during feed digestion and absorption, but suggested that may alter some blood fatty acids concentrations.     

Effect of different feeding regimes on pre‐weaning growth rumen fermentation and its influence on post‐weaning performance of lambs

Influence of pre‐weaning live weight on post‐weaning growth performance was assessed on thirty‐nine 15‐day‐old Indian native lambs, randomly fed in three equal groups until 180 days of age. During pre‐weaning phase lambs were maintained under feeding regimen of grazing (C‐0; Control), grazing and ad lib creep mixture supplementation (C‐AL) or grazing, with ad lib creep mixture and milk replacer supplementation (C‐ALMR). Lambs were allowed to suckle respective dam in morning and evening till 90 days of age, and fed ad lib green leaves of Ailanthus excelsa after grazing. After weaning all lambs were maintained on grazing and ad lib finisher concentrates supplementation. Pre‐weaning performance of lambs in terms of weaning weight (17.2 kg), average daily gain (ADG; 154 g) and feed conversion ratio 3.73 was higher (p < 0.01) in C‐ALMR lambs but total gain and ADG were similar among three groups during post‐weaning phase. However, improved pre‐weaning plane of nutrition and growth rate increased (p < 0.01) finishing weight (FW) of lambs in C‐AL, 33 kg and C‐ALMR, 32 kg. Dry matter intake was significantly (p < 0.01) higher in C‐AL and C‐ALMR lambs due to combined effect of feeding. Rumen pH was lowest (p = 0.049) in C‐AL lambs. Rumen ciliate protozoa population (10⁴/ml) decreased in C‐ALMR lambs (4.3) but increased in C‐AL lambs (50.0) more so in C‐0 Lambs (19.8). Concentrate feeding of C‐AL lamb improved nutrient digestibility. Lambs of C‐0 group consumed more DM during post‐weaning phase that improved growth performance, while nutrient digestibility was not affected by pre‐weaning nutrition. Thus, pre‐weaning nutrition has significant influence on FW, however influence of milk replacer feeding on lamb growth need further studies.     

Effect of nutrient intake on intramuscular glucose metabolism during the early growth stage in cross‐bred steers (Japanese Black male × Holstein female)

The objective was to investigate the impact of nutrient intake during the early growth period on the expression of glucose metabolism‐related genes in skeletal muscle of cross‐bred cattle. From 1.5 to 5 months of age, group H (n = 7) animals were intensively fed a high‐protein and low‐fat milk replacer [crude protein (CP) 28%; ether extracts (EE) 18%; max: 2.0 kg, 12 l/day], and group R (n = 7) animals were fed a restricted amount of normal milk replacer (CP 25%; EE 23%; max 0.5 kg, 4 l/day). From 6 to 10 months of age, group H cattle were fed a high‐nutrition total mixed ration mainly prepared from grain feed, and group R cattle were fed only roughage. Blood samples were taken from each animal at three biopsy times (1.5, 5 and 10 months of age), and the blood plasma concentration of glucose and insulin was analysed. In glucose concentration, there were no significant differences; however, the concentrations of insulin were higher in group H than in group R at 5 and 10 months of age. Muscle samples were taken by biopsy from longissimus thoracis muscle (LT) at 1.5, 5 and 10 months of age. We analysed mRNA expression levels using the quantitative real‐time polymerase chain reaction (PCR) assay for glucose transporters (GLUT1 and GLUT4), insulin receptor, phosphatidylinositol 3‐kinase (PI‐3K), protein kinase B (PKB, also known as Akt), hexokinase 1 (HK1) and tumour necrosis factor alpha (TNFα). Although no differences were detected at 1.5 and 5 months of age, at 10 months of age, GLUT1, HK1 and TNFα mRNA expression levels were significantly higher in group H than in group R. These results suggested Glut1 that affects insulin‐independently mediated glucose uptake was more responsive to improved nutrition during early growth stage than GLUT4 that insulin‐dependently mediated glucose uptake in LT of cattle.     

Effects at early stage of life of elevated milk replacer feeding on growth rate,plasma IGF‐I concentration and intestinal nutrient transporter expression in Holstein bull calves

In order to evaluate the effects of an elevated amount of modified milk replacer on body weight, daily gain, starter intake, plasma endocrine parameters and expression of nutrient transporters in small intestinal epithelia, Holstein bull calves (n = 24) were fed for 60 days either with the usual amount of 24% crude protein (CP) and 20% fat milk (CF) replacer (C group), or with a double amount of a modified milk replacer of 28% CP and 16% CF (E group). Body weight from D20 to D60 and daily gain before D40 was greater or tended to be greater for the E group than the C group. Plasma concentrations of insulin‐like growth factor‐1 (IGF‐I) and insulin were greater for the E group than the C group on D28 but not on D56, without changing plasma growth hormone levels. Gene expression for sodium‐dependent glucose transporter 1 and fatty acid translocase (CD36) was altered in day‐ and intestine‐dependent manners. From these findings, we conclude that an elevated intake of milk replacer given up to 40 days old is sufficient to enhance body weight, which may be associated with increased plasma IGF‐I concentrations, in Holstein bulls.     

Parent‐of‐origin effects on carcass traits in Japanese Black cattle

Variances caused by the differential expression of paternally and maternally imprinted genes controlling carcass traits in Japanese Black cattle were estimated in this study. Data on marbling score (BMS), carcass weight, rib thickness, rib‐eye area (REA) and subcutaneous fat thickness (SFT) were collected from a total of 13,115 feedlot steers and heifers in a commercial population. A sire–maternal grandsire model was used to analyse the data, and then, imprinting parameters were derived by replacing the genetic effect of the dam with the effect of the maternal grandsire in the imprinting model to calculate the genetic parameter estimates. The proportions of the total genetic variance attributable to imprinted genes ranged from 8.7% (SFT) to 35.2% (BMS). The remarkably large imprinting variance of BMS was mainly contributed by maternally expressed inheritance because the maternal contribution of the trait was much larger than that of the paternal trait. The parent‐of‐origin effect originating from maternal gene expression was also observed for REA. The results suggested the existence of genomic imprinting effects on the traits of the Japanese Black cattle. Hence, the parent‐of‐origin effect should be considered for the genetic evaluation of Japanese Black cattle in breeding programmes.     

Identification of the core rumen bacterial taxa and their population dynamics during the fattening period in Japanese Black cattle

The rumen microbiota comprises a vast range of bacterial taxa, which may affect the production of high-quality meat in Japanese Black cattle. The aim of this study was to identify core rumen microbiota in rumen fluid samples collected from 74 Japanese Black cattle raised under different dietary conditions using 16S rRNA gene amplicon sequencing. In the rumen of fattening Japanese Black cattle, 10 bacterial taxa, showing >1% average relative abundance and >95% prevalence, irrespective of the dietary conditions and the fattening periods, were identified as the core rumen bacterial taxa, which accounted for approximately 80% of the rumen microbiota in Japanese Black cattle. Additionally, population dynamics of the core rumen bacterial taxa revealed two distinct patterns: Prevotella spp. and unclassified Bacteroidales decreased in the mid-fattening period, whereas unclassified Clostridiales, unclassified Ruminococcaceae, Ruminococcus spp., and unclassified Christensenellaceae increased during the same period. Therefore, the present study reports the wide distribution of the core rumen bacterial taxa in Japanese Black cattle, and the complementary nature of the population dynamics of these core taxa, which may ensure stable rumen fermentation during the fattening period.     

Effects of feeding different levels of concentrate on growth and carcass characteristics in younger Japanese Black cattle

The effects of a higher concentrate feed during the raising period on the growth and carcass of Japanese Black cattle being fattened at a younger age were investigated using three pairs of artificially bred identical twins and three pairs of full‐sibs. The animals were fed the concentrate at 2.4%/day (2.4% group) and 1.2%/day (1.2% group) comparative bodyweight (BW) during the raising period. The BW and subcutaneous fat thickness were measured every month using ultrasonic equipment. The animals were slaughtered at the age of 24 months. The BW of the 2.4% group from the age of 6–10 months appeared to be higher than that of the 1.2% group (P < 0.1). The subcutaneous fat of the 2.4% group from the age of 7–11 months was thicker than that of the 1.2% group (P < 0.1). After those ages, the BW and subcutaneous fat of the two groups did not differ and there was no difference in the carcass characteristics between the two groups. Using a higher concentrate feed during the raising period for younger fattening of Japanese Black cattle influenced growth from the late half of the raising period to the early part of the fattening period.     

Effects of feeding high volumes of milk replacer on reproductive performance and on concentrations of metabolites and hormones in blood of Japanese black heifer calves

We evaluated the effects of feeding high volumes of milk replacer on growth and reproductive performances in Japanese black heifers. Fifty-one heifers were fed milk replacer at 9 L/day for 60 days (9 L × 60 days; n = 18) or 41 days (9 L × 41 days; n = 15), or at 7 L/day for 40 days (7 L × 40 days; n = 18). Artificial insemination (AI) was performed on heifers with ≥270 kg body weight and ≥116 cm body height at 300 days of age. The age at the first AI was 0.35 month later for 7 L × 40 days than the other groups (p < .01). However, age at calving did not differ among treatments (22.1 months). The interval from the first AI to pregnancy tended to be ~2 months longer for the 9 L × 60 days than the other groups (p = .07). Our results showed that feeding high volumes of milk replacer may reduce the age at calving via an improved rate of growth. In addition, we propose that feeding a maximum of 7 L milk replacer for 40 days may be the most appropriate rearing regime because the success of pregnancy per AI may be reduced in calves fed a maximum of 9 L for 41 and 60 days.     

Polymorphisms in growth hormone gene and their associations with calf weight in Japanese Black cattle

The objectives of this study were to detect effective genetic polymorphisms of bovine growth hormone (bGH) gene associated with calf weight in Japanese Black cattle. Fifty‐eight sires and 47 breeding cows were used to detect the polymorphisms in exons by single‐strand conformation polymorphism (SSCP). Four homozygous and six heterozygous SSCP genotypes were identified in exon 5. Although each single nucleotide polymorphism (SNP) had been reported, these genotypes were caused by three SNPs at the nucleotide positions 2141, 2277 and 2291. Four haplotypes C‐C‐A, G‐C‐A, C‐C‐C and G‐T‐A were newly identified. It was suggested that other haplotypes not detected in this study may not exist, considering the allele frequencies reported in Bos taurus and Bos indicus, and the migrating process of native Japanese cattle. Thereafter, we examined associations between the detected polymorphic sites in exon 5 by PCR – restriction fragment length polymorphism and calf weight using 53 breeding dams and 135 calves. The birth weights of calves with haplotype G‐C‐A are significantly lighter and calves' weights produced by cows with such haplotype are also lighter at 30 days old, using regression analysis. Although further research is necessary, these results may serve as a useful criterion to select breeding stocks, especially in maternal abilities.     

An intrauterine catch‐up growth regimen increases food intake and post‐natal growth in rats

Nutritional conditions during the intrauterine stage are an important developmental programming factor that can affect the growth and metabolic status during foetal development and permanently alter the phenotypes of newborn offspring and adults. This study was performed to examine the effects of intrauterine catch‐up growth (IUCG) on food intake, post‐natal body growth and the metabolic status of offspring and growing rats. Control pregnant rats were fed ad libitum during the entire gestation period. For the IUCG regimen, pregnant rats were fed 50% of the food of the controls from pregnancy days 4 through 11 (8 days), followed by ad libitum feeding from pregnancy days 12 through parturition. The birth weight of offspring was not affected by the IUCG regimen. At weaning, offspring from each treatment group were assigned to two groups and given either a normal diet or high‐fat diet (HFD) for 12 weeks until 103 days of age. In the normal diet group, the IUCG offspring showed a 9.0% increase (P < 0.05) in total food intake, were 11.2% heavier (p < 0.05) at 103 days of age and had an 11.0% greater (p < 0.05) daily weight gain compared with control offspring. The IUCG regimen did not affect body glucose and lipid metabolism. After exposure to the HFD, the IUCG regimen has not exacerbated metabolic disorders. In conclusion, our findings suggest that the IUCG nutritional regimen during pregnancy can increase the food intake and post‐natal body growth of offspring without inducing metabolic disorders such as obesity and insulin resistance. The IUCG nutritional regimen might be used to improve the food intake and post‐natal body growth of domestic animals.     

Identification of divergently selected regions between Japanese Black and Holstein cattle using bovine 50k SNP array

Differences between average allelic frequencies of genes that relate to traits suggest that it would be evidence of artificial selections. Sliding window approach is a useful method to identify genomic regions that have been differently selected between two breeds. The objective of this study was to identify the divergently selected regions between Japanese Black (JB) and Japanese Holstein (JH) cattle based on genotypic information obtained through a high‐density single nucleotide polymorphism (SNP) panel. After genotyping of 54 001 SNP markers on 100 animals (50 JB and 50 JH), 40 635 SNPs were suitable for the analysis. For each of these SNPs, the absolute difference between allelic frequencies of JB and JH was calculated. In the current study, 10 consecutive SNPs were defined as components of a window. For each window, the average difference in allelic frequency was calculated. This was termed sliding window average difference (SWAD). Among 40 055 windows, we focused on 39 windows with the largest SWAD. This was equivalent to 0.1% of all windows and the SWAD was more than 0.435. Some of these windows overlapped and were distributed in 11 regions. These regions were in good agreement with reported quantitative trait locus, therefore would be selection signatures and good candidates that harbor the causative mutations.     

Effects of butyrate supplementation in antibiotic‐free milk replacer and starter on growth performance in suckling calves

The aim of this study was to evaluate butyrate supplementation of antibiotic‐free milk replacer and starter on growth performance in male Holstein calves. Twenty‐nine calves were divided into two groups. Group C (n = 13) was fed antibiotic‐free milk replacer without supplementation, and Group B (n = 16) was fed antibiotic‐free milk replacer supplemented with butyrate (1.6 % DM of Gustor BP70^®). Starter in Group B contained 0.3 % DM of Gustor BP70^®. The intake of milk replacer was lower in group B than in C (p = 0.07 for the treatment x week interaction). Body weight (BW) and heart girth (HG) in group B was higher than in C during the experimental period (p = 0.07 and 0.01 for the treatment × week interaction, respectively). The duration of the weaning period in group B was shorter than in group C (p = 0.02). β‐hydroxybutyrate (BHBA) was higher in group B than in C (p = 0.04). Insulin like growth factor‐1 (IGF‐1) concentrations tended to be higher in group B than in C (p = 0.07 for treatment × week interaction). Our results show that butyrate supplementation in antibiotic‐free milk replacer and starter exerted positive effects on growth performance in suckling calves.     

Changes in concentrations of plasma metabolites and insulin-like growth factor-1 after feeding in Japanese Black and Japanese Shorthorn cattle

The aim was to characterize the changes of plasma component concentrations after feeding in Japanese Black (B) and Japanese Shorthorn (S) cattle. Eight females, five B and three S, with a mean bodyweight (standard deviation) of 282.0 (20.3) kg were selected and supplied with only water for 28 h after feeding. Blood was taken from the jugular vein at 4‐h intervals for 32 h after feeding. Metabolite (cholesterol, CL; glucose, GLU; nonesterified fatty acid, NEFA; triacylglycerol, TG; total protein, TP) and insulin‐like growth factor‐1 (IGF‐1) concentrations in plasma were measured. In both breeds GLU tended to decrease linearly with a similar slope. Differences between the initial mean NEFA at 4 h after feeding (Start) and that at 24 h after the start (End) were significant in both breeds, but S increased significantly more than B at and after 8 h from the Start. The TG in S tended to change more than in B, and CL and IGF‐1 in both breeds changed continuously at similar levels. The TP in B tended to decrease more slowly and be lower than S. The change in NEFA, especially, suggests that nutritional status sensitively reflects genetic background.     

Effects of genetic and environmental factors on muscle glycogen content in Japanese Black cattle

Monosaccharides such as glucose contribute to the development of meat flavor upon heating via the Maillard reaction; therefore, monosaccharide content is related to beef palatability. Here, we analyzed the effects of genetic and environmental factors on the content of glycogen, one of the precursors of monosaccharides, in the muscles of 958 fattened Japanese Black cattle from Yamagata Prefecture. Analysis of variance showed that muscle glycogen content was affected by the farm and postmortem periods, but not by sex, slaughter age, slaughter month or number of days detained at the slaughter yard. Additionally, consumption of digestible brown rice feed elevated muscle glycogen levels. Glycogen heritability was estimated to be 0.34, and genetic correlations between glycogen and carcass weight (CW) or beef marbling standard (BMS) were weak. The predicted breeding values varied among paternal lines. These results demonstrated that genetic factors might improve muscle glycogen content and therefore beef palatability, but do not influence CW or BMS.     

Accuracy of imputation of single nucleotide polymorphism marker genotypes from low‐density panels in Japanese Black cattle

Using target and reference fattened steer populations, the performance of genotype imputation using lower‐density marker panels in Japanese Black cattle was evaluated. Population imputation was performed using BEAGLE software. Genotype information for approximately 40 000 single nucleotide polymorphism (SNP) markers by Illumina BovineSNP50 BeadChip was available, and imputation accuracy was assessed based on the average concordance rates of the genotypes, varying equally spaced SNP densities, and the number of individuals in the reference population. Two additional statistics were also calculated as indicators of imputation performance. The concordance rates tended to be lower for SNPs with greater minor allele frequencies, or those located near the ends of the chromosomes. Longer autosomes yielded greater imputation accuracies than shorter ones. When SNPs were selected based on linkage disequilibrium information, relative imputation accuracy was slightly improved. When 3000 and 10 000 equally spaced SNPs were used, the imputation accuracies were greater than 90% and approximately 97%, respectively. These results indicate that combining genotyping using a lower‐density SNP chip with genotype imputation based on a population of individuals genotyped using a higher‐density SNP chip is a cost‐effective and valid approach for genomic prediction.     

液体饲料饲喂量对哺乳期犊牛生长性能、消化代谢的影响

研究液态饲料的饲喂量对犊牛生长发育、营养物质消化吸收的影响。选取16头犊牛,分为2个处理组,按照体重的9.5%和11.0%分别饲喂代乳粉乳液,试验全期为8周,测定犊牛的体重、测量体尺,进行消化代谢试验。两组犊牛在增重、体长指数、体躯指数上没有显著性差异(P0.05);在营养物质的消化代谢上,11.0%组在3～4周时干物质吸收量、粗蛋白吸收量及代谢能均优于9.5%组(P0.05),而在5～6周时无显著差异(P0.05)。在本试验中,液体饲料的饲喂量为犊牛体重11.0%时对犊牛的生长性能具有较好的促进作用,并且对犊牛消化吸收营养物质有积极的影响。     

A genome‐wide association study for fat‐related traits computed by image analysis in Japanese Black cattle

The objective of this study was to identify genomic regions associated with fat‐related traits using a Japanese Black cattle population in Hyogo. From 1836 animals, those with high or low values were selected on the basis of corrected phenotype and then pooled into high and low groups (n = 100 each), respectively. DNA pool‐based genome‐wide association study (GWAS) was performed using Illumina BovineSNP50 BeadChip v2 with three replicate assays for each pooled sample. GWAS detected that two single nucleotide polymorphisms (SNPs) on BTA7 (ARS‐BFGL‐NGS‐35463 and Hapmap23838‐BTA‐163815) and one SNP on BTA12 (ARS‐BFGL‐NGS‐2915) significantly affected fat percentage (FAR). The significance of ARS‐BFGL‐NGS‐35463 on BTA7 was confirmed by individual genotyping in all pooled samples. Moreover, association analysis between SNP and FAR in 803 Japanese Black cattle revealed a significant effect of SNP on FAR. Thus, further investigation of these regions is required to identify FAR‐associated genes and mutations, which can lead to the development of DNA markers for marker‐assisted selection for the genetic improvement of beef quality.     

Whole‐genome resequencing to identify candidate genes for the QTL for oleic acid percentage in Japanese Black cattle

In our previous study, we detected a QTL for the oleic acid percentage (C18:1) on BTA9 in Japanese Black cattle through a genome‐wide association study (GWAS). In this study, we performed whole‐genome resequencing on eight animals with higher and lower C18:1 to identify candidate polymorphisms for the QTL. A total of 39,658 polymorphisms were detected in the candidate region, which were narrowed to 1993 polymorphisms within 23 genes based on allele differences between the high and low C18:1 groups. We subsequently selected three candidate genes, that is, CYB5R4, MED23, and VNN1, among the 23 genes based on their function in fatty acid metabolism. In each candidate gene, three SNPs, that is, CYB5R4 c.*349G > T, MED23 c.3700G > A, and VNN1 c.197C > T, were selected as candidate SNPs to verify their effect on C18:1 in a Japanese Black cattle population (n = 889). The statistical analysis showed that these SNPs were significantly associated with C18:1 (p < 0.05), suggesting that they were candidates for the QTL. In conclusion, we successfully narrowed the candidates for the QTL by detecting possible polymorphisms located within the candidate region. It is expected that the responsible polymorphism can be identified by demonstrating their effect on the gene's function.     

Detection of candidate polymorphisms around the QTL for fat area ratio to rib eye area on BTA7 using whole‐genome resequencing in Japanese Black cattle

In our previous study, we performed genome‐wide association study (GWAS) to identify the genomic region associated with Fat area ratio to rib eye area (FAR) and detected a candidate in BTA7 at 10–30 Mbp. The present study aims to comprehensively detect all polymorphisms in the candidate region using whole‐genome resequencing data. Based on whole‐genome resequencing of eight animals, we detected 127,090 polymorphisms within the region. Of these, 31,945 were located within the genes. We further narrowed the polymorphisms to 6,044 with more than five allele differences between the high and low FAR groups that were located within 179 genes. We subsequently investigated the functions of these genes and selected 170 polymorphisms in eight genes as possible candidate polymorphisms. We focused on SLC27A6 K81M as a putative candidate polymorphism. We genotyped the SNP in a Japanese Black population (n = 904) to investigate the effect on FAR. Analysis of variance revealed that SLC27A6 K81M had a lower p‐value (p = .0009) than the most significant SNP in GWAS (p = .0049). Although only SLC27A6 K81M was verified in the present study, subsequent verification of the remaining candidate genes and polymorphisms could lead to the identification of genes and polymorphisms responsible for FAR.