Early metabolic imprinting events increase marbling scores in fed cattle

Fat deposition and partitioning for meat production in cattle and sheep

In markets for beef and sheep meat, an appropriate level of intramuscular fat (IMF) is highly desirable for meat-eating quality, but strategies to improve it usually lead to an undesirable excess in carcase fat, presenting a major challenge to livestock producers. To solve this problem, we need to understand the partitioning of fat among the major fat depots: IMF, subcutaneous fat (SCF) and visceral fat (VF). In most genotypes of cattle and sheep, the rate of accretion is lower for IMF than for SCF and VF, so genetic selection for a high level of IMF, or the use of an increased dietary energy supply to promote IMF deposition, will increase overall fatness and feed costs. On the other hand, feeding postnatal calves with excessive concentrates promotes IMF deposition, so a nutritional strategy is feasible. With genetic strategies, several problems arise: 1) positive genetic correlations between IMF, SCF and VF differ among genotypes in both cattle and sheep; 2) genotypes appear to have specific, characteristic rates of accretion of IMF during periods of growth and fattening; 3) most breeds of cattle and sheep naturally produce meat with relatively low levels of IMF, but IMF does vary substantially among individuals and breeds so progress is possible through accurate measurement of IMF. Therefore, an essential prerequisite for selection will be knowledge of the genetic correlations and fat accretion rates for each genotype. Currently, selection for IMF is based on existing technology that directly measures IMF in the progeny or siblings, or estimates IMF in live animals. New technology is needed to permit the simultaneous measurement of SCF and IMF in the field, thus opening up the possibility of accurate selection, particularly for fat partitioning in live animals. Specifically, there would be great value in detecting individuals with an IMF advantage at an early age so the generation interval could be shortened and genetic gain accelerated. Genetic gain would also be greatly aided if we could select for genes that control adipogenesis and lipogenesis and are also differentially expressed in the various depots.

Determining muscle plasticity and meat quality development of low-input extended fed market-ready steers

In March 2020, the World Health Organization declared COVID-19 a pandemic, which ultimately led to many meat processors temporarily shutting down or reducing processing capacity. This backlog in processing capacity forced many feedlots to retain cattle for longer periods of time and assume the risk of major market fluctuations. The aim of this study was to understand how a dietary insult affects meat quality and muscle metabolism in market-ready steers (590 kg). Sixteen market-ready (590 kg) commercial Angus crossbred steers were subjected to a maintenance diet of either forage or grain for 60 d. Longissimus lumborum (LL) muscle samples were collected immediately postmortem and processed for characteristics reflecting the underlying muscle fiber type and energy state of the tissue. Despite cattle being subjected to a 60-d feeding period, there were no detectable differences (P > 0.05) in carcass characteristics, color of lean, or ultimate pH (pHu). Moreover, our data show that muscle plasticity is rather resilient, as reflected by lack of significance (P > 0.05) in oxidative and glycolytic enzymes, myosin heavy chain isoforms (MyHC), myoglobin, and mitochondrial DNA (mtDNA) contents. These data show that market-ready steers are capable of withstanding a low-input feeding strategy up to 60 d without dramatically impacting underlying muscle characteristics and meat quality development.

Metabolic imprinting in beef calves supplemented with creep feeding on performance, reproductive efficiency and metabolome profile

This experiment evaluated the influence of creep feeding supplementation on productive and reproductive performance and on serum metabolome profile in Nelore (Bos indicus) heifers. Female calves were assigned to treatments: Creep (n = 190), with ad libitum access to a nutritional supplement from 70 to 220 days after birth, or Control (n = 140), without supplementation. After weaning (Day 220), both groups followed the same pasture and nutritional management. Body weight (BW) and backfat thickness (BFAT) were measured over time. Blood samples were collected at 220 and 360 days for LC-MS/MS targeted metabolomics. On day 408, during the synchronization timed artificial insemination (TAI) protocol, reproductive status (RS: diameter of uterine horn and largest follicle, and presence of CL) was assessed. Creep feeding increased BW and BFAT at weaning, but no differences in BW, BFAT, or RS after weaning were observed. Nonetheless, the pregnancy per AI (P/AI) for 1st service was 28.9% higher in the Creep group. On day 220, 11 significant metabolites influenced five metabolic pathways: Glucose-alanine cycle, alanine, glutathione, phenylalanine and tyrosine metabolism, and urea cycle. On day 360, 14 significant metabolites influenced eight metabolic pathways: Malate-aspartate shuttle, arginine and proline metabolism, urea cycle, aspartate, beta-alanine, glutamate metabolism, ammonia recycling and citric acid cycle. In conclusion, creep feeding supplementation improved calf performance and induced metabolic changes at weaning and 360 days of age. Although heifers had similar productive performance and reproductive status, when submitted to TAI, those supplemented with creep feeding had greater P/AI.

Effect of Post-Weaning Concentrate Feeding Prior to Forage Finishing on Intramuscular Fat Deposition

The objectives of this study were to examine the effects of feeding high-concentrate diets post-weaning (PW) prior to forage finishing on (1) changes in ultrasound intramuscular fat deposition and lipogenic/lipolytic gene expression during the post-weaning phase and (2) carcass characteristics and fatty acid composition after forage finishing to 487 kg. Steers were randomly assigned to one of four treatments (PW0, PW40, PW80, and PW120) at weaning to examine the time of high-concentrate feeding prior to forage finishing. The ultrasound intramuscular fat content was greater (p < 0.05) for PW120 compared to those for PW0, PW40, or PW80 at the end of the post-weaning phase. Feeding high concentrates (PW120) up-regulated (p < 0.01) the mRNA expression of fatty acid transporters and lipogenic genes and down-regulated lipolytic genes in the LM compared to PW0. Carcasses from PW120 were graded 83% Choice (p = 0.025), whereas carcasses from other post-weaning treatments (PW0, 40, or 80) were graded 25, 36, and 54% Choice, respectively, at the final harvest. The total fatty acid content of the muscle at slaughter was greater (p = 0.0004) for PW120 than PW0, PW40, and PW80. Feeding high-concentrate diets to steers post-weaning for 120 day enhanced early intramuscular fat deposition without causing major changes to the fatty acid composition of the longissimus muscle after forage finishing.

Early Weaning Possibly Increases the Activity of Lipogenic and Adipogenic Pathways in Intramuscular Adipose Tissue of Nellore Calves

This study aimed to evaluate by wide-expression profile analysis how early weaning at 120 days can alter the skeletal muscle metabolism of calves supplemented with a concentrated diet until the growth phase. Longissimus thoracis muscle samples were obtained by biopsy from two groups of calves, early weaned (EW; n = 8) and conventionally weaned (CW; n = 8) at two different times (120 days of age-T1 [EW] and 205 days of age-T2 [CW]). Next, differential gene expression analysis and functional enrichment of metabolic pathways and biological processes were performed. The results showed respectively 658 and 165 differentially expressed genes when T1 and T2 were contrasted in the early weaning group and when early and conventionally weaned groups were compared at T2. The FABP4, SCD1, FASN, LDLR, ADIPOQ, ACACA, PPARD, and ACOX3 genes were prospected in both comparisons described above. Given the key role of these differentially expressed genes in lipid and fatty acid metabolism, the results demonstrate the effect of diet on the modulation of energy metabolism, particularly favoring postnatal adipogenesis and lipogenesis, as well as a consequent trend in obtaining better quality cuts, as long as an environment for the maintenance of these alterations until adulthood is provided.

Effect of Cow-Calf Supplementation on Gene Expression, Processes, and Pathways Related to Adipogenesis and Lipogenesis in Longissimus thoracis Muscle of F1 Angus × Nellore Cattle at Weaning

The aim of this study was to identify differentially expressed genes, biological processes, and metabolic pathways related to adipogenesis and lipogenesis in calves receiving different diets during the cow-calf phase. Forty-eight uncastrated F1 Angus × Nellore males were randomly assigned to two treatments from thirty days of age to weaning: no creep feeding (G1) or creep feeding (G2). The creep feed offered contained ground corn (44.8%), soybean meal (40.4%), and mineral core (14.8%), with 22% crude protein and 65% total digestible nutrients in dry matter. After weaning, the animals were feedlot finished for 180 days and fed a single diet containing 12.6% forage and 87.4% corn-based concentrate. Longissimus thoracis muscle samples were collected by biopsy at weaning for transcriptome analysis and at slaughter for the measurement of intramuscular fat content (IMF) and marbling score (MS). Animals of G2 had 17.2% and 14.0% higher IMF and MS, respectively (p < 0.05). We identified 947 differentially expressed genes (log₂ fold change 0.5, FDR 5%); of these, 504 were upregulated and 443 were downregulated in G2. Part of the genes upregulated in G2 were related to PPAR signaling (PPARA, SLC27A1, FABP3, and DBI), unsaturated fatty acid synthesis (FADS1, FADS2, SCD, and SCD5), and fatty acid metabolism (FASN, FADS1, FADS2, SCD, and SCD5). Regarding biological processes, the genes upregulated in G2 were related to cholesterol biosynthesis (EBP, CYP51A1, DHCR24, and LSS), unsaturated fatty acid biosynthesis (FADS2, SCD, SCD5, and FADS1), and insulin sensitivity (INSIG1 and LPIN2). Cow-calf supplementation G2 positively affected energy metabolism and lipid biosynthesis, and thus favored the deposition of marbling fat during the postweaning period, which was shown here in an unprecedented way, by analyzing the transcriptome, genes, pathways, and enriched processes due to the use of creep feeding.

Supplementation with rumen-inert fat in the growing phase altered adipogenic gene expression and the size and number of adipocytes in Hanwoo steers

We hypothesized that the provision of rumen-inert fat (RIF) to growing cattle (9 to 13 mo of age) would affect the expression of genes involved in lipid metabolism and thereby affect the size and number of adipocytes of steers slaughtered at 30 mo of age. Thirty steers with an average initial body weight (BW) of 239 ± 25 kg were allocated to six pens, balanced for BW and genetic merit for marbling, and assigned to one of two treatment groups: control (only basal diet) or test diet (basal diet with 200 g of RIF per day, on an as-fed basis) for 5 mo. Biopsy samples of longissimus lumborum (LM) muscle were then collected for analysis of fatty acid composition and gene expression. Both groups were then fed the same basal diets during the early and late fattening phases, without RIF, until slaughter (average shrunk BW = 759 kg). Supplementation with RIF increased the longissimus thoracis (LT) intramuscular fatty acid concentration at slaughter (P = 0.087) and numerically increased the quality grade score (P = 0.106). The LM intramuscular relative mRNA expression of genes such as PPARα, ZFP423 and SREBP1, FASN, SCD, FABP4, GPAT1, and DGAT2 were downregulated (P < 0.1) following RIF supplementation. Supplementation of RIF decreased (P < 0.1) diameter and concomitantly increased intramuscular adipocytes per viewing section at slaughter. This likely was caused by promotion of triacylglycerol hydrolysis during the growing phase. Another possible explanation is that the relative mRNA expression of gene ATGL was upregulated by RIF supplementation during the growing (P < 0.1) and the fattening phases (P < 0.05), while the genes associated with fatty acid uptake (FABP4) and esterification (DGAT2) were downregulated during the growing phase and upregulated (P < 0.1) during the fattening phase. This implies that the lipid turnover rate was higher for steers during the growing than fattening phase. This study demonstrated that RIF supplementation during the growing phase induced a carryover effect on the lipogenic transcriptional regulation involved in adipocyte lipid content of intramuscular adipose tissue; increased triacylglycerol hydrolysis during the growing phase subsequently was followed by increased lipid accumulation during the fattening phases.

Effect of weaning strategy and backgrounding management on growth performance, carcass characteristics, and mRNA expression in the longissimus muscle of beef steers

We evaluate the effect of the weaning strategy (WS; early, 130 ± 21 d vs. normal, 187 ± 20 d) and backgrounding management (BGM) on growth, carcass characteristics, and relative mRNA expression in the longissimus muscle (LM) of beef steers. One hundred and twenty Angus × SimAngus-crossbred steers (body weight (BW) = 130 ± 11.2 kg) were used in a randomized complete block design. Steers, blocked by age and BW, were randomly assigned to one treatment (2 × 2 factorial). Treatments consisted of early weaned (EW) or normal weaned (NW) steers subsequently backgrounded (BG) on either a forage-based (FB) or concentrates-based (CB) diet. The EW steers (d 0) were ad libitum-fed a grain-based diet for 49 d until nursing calves were NW. Steers were ad libitum-fed either a FB diet for 214 d or a CB diet for 95 d afterward. Steers were finished on a high-grain diet until harvested at an estimated constant 12th-rib fat thickness (1.5 cm). Expression of mRNA in the LM was measured over time. Data were analyzed using PROC MIXED in SAS. The EW steers were heavier (P ˂ 0.01) at the beginning of the backgrounding and finishing period. When the finishing phase began, steers FB were heavier (P ˂ 0.01) than CB steers. There was a tendency for a WS × BGM interaction (P = 0.08) for final BW, where NW-FB steers were heavier than the steers on the other three treatments, which do not differ between them. In the finishing phase, steers BG on a FB diet had greater dry matter intake and average daily gain, but lower gain-to-feed ratio (P ˂ 0.01). There was a WS × BGM interaction (P = 0.03) for days on feed (DOF) in the finishing diet, where backgrounding steers in a FB diet decreased DOF required to reach the harvesting target among EW steers, but not within NW steers. No interactions or treatment effects (P ≥ 0.17) were detected for marbling score (MS). For ZFP423, EW steers showed a greater mRNA expression on d 112 and a lower expression on d 255 than NW steers (P ˂ 0.01). In d 57, steers BG on a CB diet presented a greater delta-like homolog 1 mRNA expression than steers BG on a FB diet, whereas in d 255, this was inverted (P ˂ 0.01). For CCAAT/enhancer binding protein D (C/EBPD) mRNA expression, a tendency for a WS × BGM interaction was observed (P = 0.06), where a greater expression of C/EBPD was observed in steers BG on a FB diet among EW steers, but not within NW steers. In this study, early grain feeding followed by different BGM does not support MS improvements of beef carcasses.

Effect of grain inclusion rates in diets provided to early-weaned calves and steroidal implants utilization on growth performance and carcass characteristics of beef steers

One hundred and twenty-one Angus × SimAngus-crossbred steers (body weight (BW) = 159 ± 22 kg) were used to evaluate the effects of different grain inclusion (GI) rates in diets provided to early-weaned calves and steroidal implants (SI) utilization on growth performance and carcass characteristics, particularly intramuscular fat deposition, of beef steers. The experiment was conducted as a randomized complete block design with a 2 × 2 factorial arrangement of treatments, consisting of two GI rates (35% vs. 58%, dry matter (DM) basis), each one associated or not to steroidal implant utilization (no implants vs. 80 mg trenbolone acetate (TA) + 16 mg estradiol followed by 120 mg TA + 24 mg of estradiol). After being early-weaned (124 ± 14 d of age), steers were offered an average of 4.5 kg/d (DM basis) of a concentrate-based diet with a greater or lesser GI rate for 60 d. After being fed a concentrate-based diet with different GI rates for 60 d, steers were fed a common backgrounding diet for 56 d and subsequently fed a common high-grain diet until harvested at a constant final BW (620 kg). Steers were not implanted until the beginning of the backgrounding phase and then re-implanted when initiating the finishing phase. Data were analyzed using PROC MIXED in SAS. There were no GI × SI interactions (P ≥ 0.62) for any of the growth performance parameters throughout the experimental period. Implanted steers tended to have a greater average daily gain (P = 0.10) during the finishing phase than nonimplanted steers. For the 12th rib fat thickness and yield grade (YG), a GI × SI interaction (P = 0.03) and a tendency for a GI × SI interaction (P = 0.10) was detected, respectively. Nonimplanted steers fed diets with greater GI rates presented the greatest 12th rib fat thickness and tended to have the greatest YG among treatments. No other interactions (P ≥ 0.33) were observed for the hot carcass weight, Longissimus muscle (LM) area, quality grade, marbling score, and kidney-pelvic-heart fat content. Steers fed diets with lesser GI rates tended to have a greater LM area than steers fed diets with greater GI rates (P = 0.10). Results from this experiment indicate that varying GI rates in diets provided to early-weaned calves and subsequent implantation with steroidal hormones did not affect marbling deposition.

Main regulatory factors of marbling level in beef cattle

The content of intramuscular fat (IMF), that determines marbling levels is considered as one of the vital factors influencing beef sensory quality including tenderness, juiciness, flavour and colour. The IMF formation in cattle commences around six months after conception, and continuously grows throughout the life of the animal. The accumulation of marbling is remarkably affected by genetic, sexual, nutritional and management factors. In this review, the adipogenesis and lipogenesis process regulated by various factors and genes during fetal and growing stages is briefly presented. We also discuss the findings of recent studies on the effects of breed, gene, heritability and gender on the marbling accumulation. Various research reported that feeding during pregnancy, concentrate to roughage ratios and the supplementation or restriction of vitamin A, C, and D are crucial nutritional factors affecting the formation and development of IMF. Castration and early weaning combined with high energy feeding are effective management strategies for improving the accumulation of IMF. Furthermore, age and weight at slaughter are also reviewed because they have significant effects on marbling levels. The combination of several factors could positively affect the improvement of the IMF deposition. Therefore, advanced strategies that simultaneously apply genetic, sexual, nutritional and management factors to achieve desired IMF content without detrimental impacts on feed efficiency in high-marbling beef production are essential.

Effects of Megasphaera elsdenii administration on performance and carcass traits of finishing Bos indicus feedlot cattle

This study evaluated the effects of Megasphaera elsdenii administration at the beginning of the feedlot period on performance of Bos taurus indicus bulls. On d 0, 383 Nellore bulls (initial shrunk body weight 384 ± 29.2 kg; initial age = 24 ± 2 mo) were assigned to treatments in a randomized complete block design. Treatments consisted of 1) 14 d adaptation diet and transition to a finishing diet (CONT), 2) CONT plus oral administration of 20 mL of Lactipro-NXT (M. elsdenii) on d 0 of the study (MEG-14), 3) CONT diet, consisting of 6 d of adaptation diet plus oral administration of 20 mL of Lactipro-NXT on d 0 of the study (MEG-6), and 4) No adaptation diet and oral administration of 20 mL of Lactipro-NXT on d 0 of the study (MEG-0). Experimental period lasted 119 d. No treatment effects were observed for any of the performance parameters evaluated herein (P ≥ 0.15). Nonetheless, a treatment × wk interaction was observed for DM, NE_m, and NE_g intakes (P < 0.0001). For all these parameters, MEG-0 and MEG-6 had a reduced intake vs. MEG-14 and CONT in the first wk of the study (P ≤ 0.05). For the carcass traits, no effects were observed for HCW (P ≥ 0.24), whereas MEG-6 had a greater REA when compared with MEG-0 and MEG-14 (quadratic effect; P = 0.04) and MEG-administered bulls tended to have a greater BFT vs. CONT (P = 0.08). In summary, M. elsdenii administration at the beginning of the feedlot period did not improve performance, whereas reducing the length of the adaptation period for 6 d improved REA of finishing Bos taurus indicus bulls.

Impacts of Nutritional Management During Early Postnatal Life on Long-Term Physiological and Productive Responses of Beef Cattle

Effective early postnatal nutritional management is a crucial component of livestock production systems, and nutrient manipulation during this period has been shown to exert long-term consequences on beef cattle growth and physiology. Metabolic imprinting defines these biological responses to a nutritional intervention early in life that permanently alter physiological outcomes later in life. Early weaning has been used to study metabolic imprinting effects, given that it allows for nutritional manipulation of animals at a young age. This practice has been shown to enhance carcass characteristics in feedlot cattle and accelerate reproductive development of females. Another strategy to study the effects of metabolic imprinting without the need for early weaning is to provide supplements via creep feeding. Providing creep feed to nursing cattle has resulted in transient and long-term alterations in cattle metabolism, contributing to increased reproductive performance of developing heifers and enhanced carcass quality of feeder cattle. Collectively, results described herein demonstrate nutrient manipulation during early postnatal life exerts long-term consequences on beef cattle productivity and may be a strategy to optimize production efficiency in beef cattle systems.

Effects of early high nutrition related to metabolic imprinting events on growth, carcass characteristics, and meat quality of grass-fed Wagyu (Japanese Black cattle)

The study was conducted to clarify how early high plane of nutrition related to metabolic imprinting affected growth, carcass characteristics, and meat quality of grass-fed Wagyu (Japanese Black cattle). Wagyu steers were allocated randomly into 2 dietary groups: (1) steers fed milk replacer (crude protein 26.0%, crude fat 25.5%; maximum intake 0.6 kg/d) until 3 mo of age and then fed roughage (orchard grass hay) ad libitum from 4 to 10 mo of age (roughage group, RG; n = 11); (2) steers fed milk replacer (maximum intake of 1.8 kg/d) until 3 mo of age and then fed a high-concentrate diet from 4 to 10 mo of age (early high nutrition, EHN; n = 12). After 11 mo of age, all steers were fed roughage ad libitum until 31 mo of age and then slaughtered. Growth performance, carcass traits, longissimus muscle (LM) meat quality and intramuscular fat (IMF) content, plasma insulin-like growth factor I (IGF-I) concentration, and bone mineral density were measured. Body weight was greater in EHN steers (571 kg) than RG steers (520 kg; P < 0.01). Plasma IGF-I levels were higher in EHN steers than in RG steers at 3, 10, and 14 mo of age (P < 0.01, P < 0.005, P < 0.001, respectively); however, plasma IGF-I levels were lower in EHN steers compared with RG steers at 30 mo of age (P < 0.01). The total weight of the muscles and bones of the left half of the carcass was not different between the 2 groups (P = 0.065). Five of the 19 muscles investigated (semimembranosus, P = 0.036; infraspinatus, P = 0.024; supraspinatus, P = 0.0019; serratus ventralis cervicis, P = 0.032; serratus ventralis thoracis, P = 0.027) were heavier in EHN steers. Total fat weight in the left half of the carcass was 30% greater (P = 0.025) in HNE carcasses. Subcutaneous and perirenal fat weights were 53% and 84% greater (P = 0.008, P = 0.002, respectively) in EHN carcasses. The LM IMF content was greater in EHN loins (13.2%) compared with RG loins (9.4%) at 31 mo of age (P = 0.038); however, no differences were found for shear force, tenderness, and cook loss. These results suggested early high-nutrition affected the growth and meat quality of livestock.

The Effects of Age at Weaning and Length of Lipid Supplementation on Growth, Metabolites, and Marbling of Young Steers

Simple Summary

Consumers value quality beef and producers are starting to look at the ways production decisions affect the long-term performance of the animals. Early weaning is a production option in many beef cattle production environments. We are looking at the addition of rumen by-pass lipids in addition to early weaning to increase the marbling of steers. The supplementation of rumen protected lipids’ increased plasma concentrations of fatty acids. Supplementation of rumen-protected lipids improved carcass quality of young steers by increasing marbling scores and lipid concentration of steaks without negatively impacting dressing percentage. Therefore, a combination of early weaning and rumen by-pass lipid supplementation can be used as management practices to meet current consumer demands.

Abstract

The objective of this study was to determine how weaning age, days on supplements, and lipid supplementation affected the growth and marbling deposition of steers. Steers from a single sire were early weaned (n = 24) at 150 ± 11 days of age or traditionally weaned (n = 24) at 210 ± 11 days of age. Steers were assigned to control (n = 12/weaning group) or an isocaloric, isonitrogenous rumen by-pass lipid (RBL, n = 12/weaning group) for either 45 (n = 6/treatment) or 90 (n=6/treatment) days then harvested. Steer body weight (BW) was recorded on days −14 and −7, then BW and blood samples were collected on days 0, 22, 45, 66, and 90. The right rib section of each animal was collected for proximate analysis. Longissimus dorsi from RBL steers had increased lipids compared with control steers (3.6 ± 0.2 vs. 2.4 ± 0.2% on a wet basis; p < 0.0001). Steers fed for 90 days had greater (p = 0.02) concentrations of Longissimus dorsi lipid (3.3 ± 0.2%) than those fed for 45 days (2.7 ± 0.2%). There was a weaning age by treatment by days on feed interaction for intramuscular adipocyte diameter (p = 0.02) in which early weaned RBL fed for 90 days steers had an increased adipocyte diameter compared to the early weaned control fed for 90 and early weaned fed for 45 days steers with all other treatment groups as intermediates. Supplementation of RBL increased concentrations of C18:2, C20:4, and total fatty acids on days 45 and 90 (p ≤ 0.05). Data show that RBL supplementation increased the marbling content of the Longissimus dorsi. Furthermore, a longer period of supplementation resulted in increased adipose diameter.

Influence of Megasphaera elsdenii and feeding strategies on feedlot performance, compositional growth, and carcass parameters of early weaned, beef calves

Simmental–Angus calves [n = 135; 72 steers and 63 heifers; body weight (BW) = 212.4 kg ± 36.1] were early weaned (~5 mo) to evaluate multiple feeding regimens (conventional vs. aggressive energy diets ± Megasphaera elsdenii NCIMB 41125 (M. elsdenii culture (MEC); Lactipro Advance; MS Biotec Inc., Wamego, KS) in order to elucidate the optimal development strategy. Objectives were measured by tracking the effects of caloric density and oral drenching of growing phase performance and subsequent carcass traits. The 72-d experiment featured three groups: 1) control (CON), fed exclusively a 35% roughage diet; 2) aggressive (AGR), fed a blend of a 10% and 35% roughage diets; 3) MEC, fed the same diet as AGR and drenched with 50 mL of M. elsdenii NCIMB 41125 on day 1. A subset of calves (n = 45) was equipped with wireless rumination tags (Allflex Flex Tag; SCR Engineers, Ltd; Netanya, Israel), which logged daily rumination and general activity. Skeletal growth variables were assessed by measuring wither and hip height pretrial and posttrial. Ultrasonography provided additional resolution concerning growing phase compositional gain, which was later verified by carcass data collection. Data were analyzed as a nested analysis of variance with BW and gender serving as blocking factors. The increased caloric density of the diets administered to MEC and AGR calves resulted in greater average daily gain and gain:feed values compared with CON even during the first 21 d of diet acclimation (P ≤ 0.05). Additional fiber concentration of CON diets led to increased rumination times in 9 of the 10 wk of trial (P ≤ 0.10). No differences amongst treatments were detected for skeletal variables or ultrasound 12th rib fat. Cattle fed CON diets posted 3.4% inferior BW at the end of the growing period trial and a 3.8% reduction in hot carcass weight (HCW), reinforcing the theory that intensifying caloric intake during the growing phase does not compromise future feedlot performance. Ultrasound marbling scores for MEC-treated cattle were 19° greater than AGR treated cattle (P ≤ 0.05) at the end of the growing phase trial. Nearly the exact same advantage (22°) was observed in the cooler 5 mo later (P = 0.42). Implying MEC metabolically imprinted cattle to favor marbling development. It appears that maximizing dietary caloric density in light-weight calves does not adversely affect the growth curve, while oral dosing of MEC during the growing period may be a precursor for enhanced quality grade.

Supplementing calcium salts of soybean oil to beef steers early in life to enhance carcass development and quality1

This study evaluated the effects of supplementing Ca salts of soybean oil (CSSO) to beef steers at 2 mo of age via creep-feeding, and/or during a 40-d preconditioning period on performance and carcass development responses. A total of 64 steers were enrolled in this study over 2 yr (32 steers per year), with 4 periods each year: creep-feeding (CF; day 0 to 60), preweaning (day 61 to weaning on day 124 and 127 of year 1 and 2, respectively), preconditioning (PC; day 132 to 172 in year 1 and day 135 to 175 of year 2), and feedlot (feedlot arrival to slaughter, day 173 to 378 in year 1 and day 176 to 385 in year 2). On day 0 steers were ranked by body weight (BW) and age (114 ± 4 kg of BW; 66.1 ± 0.9 d of age) and allocated to 1 of 16 pens. Pens were randomly assigned to receive CSSO during CF (80 g/d per steer) and/or PC (150 g/d per steer) in a 2 × 2 factorial arrangement of treatments. During CF and PC, nonsupplemented steers (CON) were provided an isolipidic prilled saturated fat supplement. Steer BW was recorded on day 0, 60, at weaning, and prior to feedlot shipping. Carcass traits were recorded upon slaughter. On day 0, 60, at weaning, prior to feedlot shipping, and during the feedlot period, blood samples were collected and longissimus muscle (LM) biopsies were collected. On day 60, steers that received CSSO during CF had greater (P < 0.01) plasma concentrations of linoleic and ω-6 compared with CON (CF treatment × day; P ≤ 0.05). Steers that received CSSO during PC had greater (P < 0.01) plasma concentrations of linoleic, ω-6, and total fatty acids compared with CON at feedlot shipping (PC treatment × day; P ≤ 0.05). A PC treatment × day interaction was also detected (P = 0.04) for mRNA expression of peroxisome proliferator-activated receptor gamma (PPAR-γ), which was greater (P = 0.04) at feedlot shipping for steers receiving CSSO during PC. Interactions between CF treatment × day were detected (P ≤ 0.01) for mRNA expression of adipocyte fatty acid-binding protein, fatty acid synthase, PPAR-γ, and stearoyl-CoA desaturase, which were greater (P ≤ 0.02) in the feedlot in steers receiving CSSO during CF. No treatment differences were detected for (P ≥ 0.18) performance or carcass traits, including marbling and backfat thickness. Results from this study suggest that supplementing CSSO to suckled beef steers via creep-feeding upregulated mRNA expression of the adipogenic genes investigated herein later in life. These outcomes, however, were not translated into improved carcass quality.

Palatability of Beef Strip Loin Steaks Following Variable Length High-Concentrate Diet Exposure Prior to Pasture-Finishing

Proximate composition, Warner-Bratzler shear force (WBSF), consumer sensory traits, fatty acid composition, and volatile flavor compounds were assessed on steaks from USDA Select strip loins (n = 40; 8/treatment) representing grass-fed beef sourced from New Zealand (NZ) with marbling consistent with USDA Select along with strip loins from four feeding treatments designed to evaluate the effects of early exposure to grain-based diets for 0 d (0D), 40 d (40D), 80 d (80D), or 120 d (120D) prior to pasture-finishing on meat quality and composition. Percent fat, moisture, and protein and WBSF did not differ (P > 0.05), but percent ash was decreased in 120D samples compared to those from NZ, 0D, and 40D (P < 0.05). Consumer scores for all traits differed among samples from the treatments (P < 0.05), with steaks from NZ receiving greater scores for flavor liking than those from 0D, 40D, and 80D (P < 0.05). Consumers also rated NZ and 120D samples greatest for overall liking (P < 0.05). Saturated fatty acids were decreased, and monounsaturated fatty acids were increased in NZ samples compared to samples from all other treatments (P < 0.05), and conjugated linoleic acid was least in samples from NZ (P < 0.05). The ratio of omega-6 to omega-3 fatty acids was greater in 80D and 120D samples than those from all other treatments (P < 0.05). Non-enzymatic browning-derived ketones and 2-pentylfuran were increased in samples from NZ compared to those from all other treatments (P < 0.05), and differences among treatments in lipid-derived compounds were primarily of alcohols and aldehydes. Early exposure to grain-based diets for 120 d prior to pasture-finishing produces beef that is comparable to grass-fed beef from New Zealand in palatability but differs in chemical composition.

Timing of Exposure to High-Concentrates versus High-Quality Forages on Growth and Marbling Deposition in Steers

Forty Angus-cross steers (280 ± 21.4 kg BW, 8 mo.) were used to examine the effects of exposure to 2 diets [high concentrate diets (CONC) versus high quality forages (FOR)] during 2 time periods [early (EARLY; at 30-d post weaning) or late (LATE; just prior to slaughter)] on animal growth, marbling deposition and tenderness. Steers were blocked by weight and randomly assigned to four dietary treatments: 1) CONC-FOR, 2) CONC-CONC, 3) FOR-CONC, or 4) FOR-FOR. Exposure to CONC during the EARLY or LATE period increased (P < 0.05) growth and fat deposition compared to FOR-FOR. Hot carcass weight was greater (P < 0.05) for CONC-CONC and FOR-CONC steers than FOR-FOR and CONC-FOR due to changes in dressing percent. Marbling score was greater (P < 0.05) for CONC-CONC and CONC-FOR compared to FOR-FOR. Exposure to CONC during the EARLY period (CONC-FOR and CONC-CONC) increased (P < 0.05) n-6 polyunsaturated fatty acids (PUFA) deposition in longissimus muscle (LM) and subcutaneous adipose tissue (SQ); whereas, exposure to CONC during the LATE period (CONC-CONC and FOR-CONC) reduced (P < 0.05) n-3 PUFA, trans-11 octadecenoic acid and cis-9 trans-11 isomer of conjugated linoleic acid (CLA). Warner-Bratzler shear force at d 2 and 7 of postmortem aging in ribeye steaks from CONC-CONC and FOR-CONC was greater (P < 0.05) than FOR-FOR and CONC-FOR. Lipogenic gene expression was up-regulated (P < 0.05) and lipolytic gene expression was downregulated (P < 0.06) in SQ from CONC-CONC and FOR-CONC compared to FOR-FOR. Overall, exposure to CONC in both periods increased growth rate and marbling deposition but LATE exposure had the greatest impact on adipose lipogenesis and lipolysis, fatty acid composition, and tenderness.

The Japanese Wagyu beef industry: current situation and future prospects - A review

In Japan, Wagyu cattle include four Japanese breeds; Black, Brown, Shorthorn, and Polled. Today, the renowned brand name Wagyu includes not only cattle produced in Japan, but also cattle produced in countries such as Australia and the United States. In recent years, the intramuscular fat percentage in beef (longissimus muscle) from Japanese Black cattle has increased to be greater than 30%. The Japanese Black breed is genetically predisposed to producing carcass lipids containing higher concentrations of monounsaturated fatty acids than other breeds. However, there are numerous problems with the management of this breed including high production costs, disposal of untreated excrement, the requirement for imported feed, and food security risks resulting from various viral diseases introduced by imported feed. The feeding system needs to shift to one that is more efficient, and improves management for farmers, food security for consumers, and the health environment for residents of Japan. Currently, we are developing a metabolic programming and an information and communications technology (ICT, or Interne of Things) management system for Wagyu beef production as future systems. If successful, we will produce safe, high-quality Wagyu beef using domestic pasture resources while solving the problems of how to utilize increasing areas of abandoned agricultural land and to make use of the plant-based feed resources in Japan’s mountainous areas.

Genetic, management, and nutritional factors affecting intramuscular fat deposition in beef cattle - A review

Intramuscular fat (IMF) content in skeletal muscle including the longissimus dorsi muscle (LM), also known as marbling fat, is one of the most important factors determining beef quality in several countries including Korea, Japan, Australia, and the United States. Genetics and breed, management, and nutrition affect IMF deposition. Japanese Black cattle breed has the highest IMF content in the world, and Korean cattle (also called Hanwoo) the second highest. Here, we review results of research on genetic factors (breed and sex differences and heritability) that affect IMF deposition. Cattle management factors are also important for IMF deposition. Castration of bulls increases IMF deposition in most cattle breeds. The effects of several management factors, including weaning age, castration, slaughter weight and age, and environmental conditions on IMF deposition are also reviewed. Nutritional factors, including fat metabolism, digestion and absorption of feed, glucose/starch availability, and vitamin A, D, and C levels are important for IMF deposition. Manipulating IMF deposition through developmental programming via metabolic imprinting is a recently proposed nutritional method to change potential IMF deposition during the fetal and neonatal periods in rodents and domestic animals. Application of fetal nutritional programming to increase IMF deposition of progeny in later life is reviewed. The coordination of several factors affects IMF deposition. Thus, a combination of several strategies may be needed to manipulate IMF deposition, depending on the consumer’s beef preference. In particular, stage-specific feeding programs with concentrate-based diets developed by Japan and Korea are described in this article.

The effect of supplementing rumen undegradable unsaturated fatty acids on marbling in early-weaned steers

The objective of this study was to determine if supplementation with a rumen undegradable unsaturated fatty acids (FA) source improved marbling deposition in early-weaned steers. All steers (Angus, = 23; Angus × Hereford, = 24) were weaned at 150 ± 5 d of age. Steers were blocked by BW and breed and then randomly assigned to either control (CON; average 1.5 kg of corn gluten feed [CGF], = 23) or isocaloric supplementation containing a rumen undegradable fat source (RUF; 200 g of Megalac-R added to an average of 1.06 kg of CGF, = 24) offered 5 d/wk for 110 d. All steers had ad libitum access to pastures throughout treatment and received supplements individually. Steer BW and blood samples were collected at 0, 55, and 110 d of supplementation, and real-time ultrasound measurements were collected at d 110. Following treatment, steers were transported to Oklahoma State University for finishing and subsequent harvesting at a commercial plant. All data were analyzed using the PROC MIXED procedure of SAS either as repeated measures or ANOVA depending on parameters. There were no significant changes in BW from the beginning of treatment to harvest due to treatment. Ultrasound data showed that RUF steers tended ( = 0.08) to have more i.m. fat than CON at d 110. Serum concentrations of FA showed a treatment × day interaction ( < 0.02) for 16:0, 18:0, 18:1-9, 18:2, 20:4, and total FA. These specific FA concentrations slightly increased in CON steers, but there was a more pronounced increase in the concentration of these FA across the supplementation period in RUF steers. Serum triglyceride and cholesterol concentrations were increased ( < 0.01) on d 55 and 110 in RUF steers compared with those in CON steers. Serum leptin concentration in RUF steers was greater ( < 0.01) than CON steers at d 110. After harvest, RUF carcasses had greater ( = 0.01) marbling scores than those of CON carcasses. All other carcass measures were similar between treatments. The percentage of total lipids was increased ( = 0.011) in steaks from RUF compared to CON. There was a decrease ( < 0.05) in adipocyte diameter in i.m. fat depot of RUF steers compared to CON. There was also a tendency ( = 0.06) for RUF steers to have a greater percentage of 20 to 30 μm adipocytes in their i.m. depot than CON steers. This study indicates that supplementation of unsaturated FA can positively impact marbling deposition in early-weaned steers without impacting other carcass measures.

Postweaning substitution of grazed forage with a high-energy concentrate has variable long-term effects on subcutaneous fat and marbling in Bos taurus genotypes

The objective of this study was to quantify the effects and interactions of stage of growth and genotype on commercial carcass traits and intramuscular fat (IMF) content in 5 muscles of steers ( = 165) and to test the hypothesis that substituting pasture with a high-energy concentrate during the immediate postweaning period increases IMF. Cattle of 3 genotypes (Angus, Hereford, and Wagyu × Angus; = 55/genotype) were selected at weaning from commercial herds, targeting genotypic differences in marbling and subcutaneous fatness. Following weaning, steers were fed for 168 d within 2 different improved, temperate pasture-based nutritional systems: a forage-only system (FS) and forage with high-energy supplemented system (SS), with 2 replicates per system. The supplement was fed at a level of 1% of average BW adjusted every 2 wk to provide an estimated 50% of energy requirements for 168 d from weaning. Pasture on offer in both systems was managed to match the BW of the FS and SS steers during the postweaning treatment period to avoid confounding due to differences in growth rate during this period. Steers were then regrouped into 2 replicates and backgrounded on improved, temperate pasture for 158 d and then grain fed within 1 group for 105 d (short fed) or 259 d (long fed). Groups were slaughtered at commencement (d 0) and end of postweaning nutritional treatments (d 168), end of backgrounding (d 326), and after short (d 431) or long feedlotting (d 585). Serial slaughter stage had an effect on all traits assessed ( < 0.01). The FS steers had more rib fat ( < 0.01) and higher Meat Standards Australia marbling score ( < 0.05) and a tendency ( < 0.10) to have greater eye muscle area than the SS steers throughout the study. Genotypic differences were evident ( < 0.05) for all traits assessed except HCW, dressing percentage, rib fat depth, ossification score, ultimate pH, and IMF in the semitendinosus muscle. The results for marbling and IMF do not support the use of a high-energy feed as a substitute for an equivalent amount of energy from pasture during the immediate postweaning period to enhance development of marbling.

Acetate and glucose incorporation into subcutaneous, intramuscular, and visceral fat of finishing steers

The objectives of this study were to assess the effects of early grain feeding on acetate and glucose turnover rates and acetate and glucose preference for palmitate synthesis by subcutaneous fat (SCF), intramuscular fat (IMF), and visceral fat (VF) in finishing steers. Sixteen Angus × Simmental steers were used in the study; 8 were early weaned (EW) and fed a high-grain diet immediately after weaning for 100 or 148 d, and 8 remained with their dams on pasture until weaning at 202 ± 5 or 253 ± 5 d of age. Normal weaned (NW) and EW animals were combined and grazed to 374 ± 5 or 393 ± 5 d of age, when they were placed on a corn silage-based finishing ration until they achieved a SCF thickness of 1.0 to 1.2 cm (494 ± 17 d of age for EW steers and 502 ± 12 d of age for NW steers). Immediately before harvest, steers were continuously infused for 12 h with [2H3] acetate (1.63 mmol/min; n = 8) or [U-13C6] glucose (0.07 mmol/min; n = 8). Blood samples were collected before initiation of infusions and at the end of the infusion from 8 animals or at 1-h intervals for the first 11 h and at 15-min intervals for the last hour of infusion for the other 8 animals. Adipose tissue samples from SCF, IMF, and VF depots were collected at harvest, and lipids were extracted. Plasma enrichments of acetate and glucose and palmitate enrichment in each depot were used to calculate plasma turnover rates and fractional synthesis rates (FSR; % per h) of palmitate from each isotope. Early weaned steers had greater marbling scores compared to NW steers ( P< 0.05). Plasma turnover rates and FSR for EW and NW steers were similar except for SCF, where a greater FSR from acetate was observed for EW steers. It is possible the greater FSR for SCF was due to harvesting the animals at a slightly more advanced stage of conditioning as evidenced by the trend for greater 12th rib fat (P = 0.07). Plasma acetate turnover and palmitate FSR from acetate were much greater (P < 0.05) than the corresponding rates from glucose, supporting the primary role of acetate as an energy source and the primary substrate for lipid synthesis across fat depots. However, FSR from acetate and glucose were not different among depots, suggesting that any potential effects of dietary starch on differential deposition of energy in SCF and IMF are not substrate driven.

Creep-feeding to stimulate metabolic imprinting in nursing beef heifers: impacts on heifer growth, reproductive and physiological variables

This experiment compared growth, physiological, and reproductive responses of beef heifers with (MI) or without (CON) access to a creep-feeder, as a manner to stimulate metabolic imprinting while nursing their dams. On day 0, 60 Angus × Hereford heifers were ranked by BW and age (140 ± 3 kg and 68±3 days), and assigned to pairs so all ranking criteria were similar between heifers within each pair. On day 1, pairs were randomly assigned to MI (n=15) or CON (n=15). From day 1 to 51, MI pairs and their dams were allocated to 15 drylot pens where heifers had ad libitum access to a corn-based supplement through a creep-feeder. The CON pairs and their dams were maintained in an adjacent single drylot pen. From day 52 to 111, treatments were managed as a single group on a semiarid range pasture. On day 111, heifers were weaned and allocated to two pastures (one pasture/treatment), receiving hay and a corn-based concentrate until day 326. Heifer BW was recorded before and at the end of the creep-feeding period (day 1 to 51), and on days 112 and 326. On days 0, 51, 111, 187, 261, and 325, jugular blood was collected and real-time ultrasonography for longissimus muscle depth and backfat thickness assessment was performed. Blood was also collected every 10 days from days 113 to 323 for puberty evaluation via plasma progesterone. Liver and subcutaneous fat biopsies were performed on days 51, 111, 261 and 325. Average daily gain was greater (P<0.01) for MI than CON from day 1 to 51, tended (P=0.09) to be greater for CON than MI from day 112 to 326, while BW on day 326 was similar between treatments. On day 51, MI had greater (P ⩽ 0.01) plasma IGF-I and glucose concentrations, as well as mRNA expression of hepatic pyruvate carboxylase and adipose fatty acid synthase than CON. On days 261 and 325, plasma insulin concentrations were greater (P ⩽ 0.03) in CON than MI. Mean mRNA expression of hepatic IGF-I and adipose peroxisome proliferator-activated receptor gamma were greater (P ⩽ 0.05) in MI than CON. No treatment effects were detected for puberty attainment rate. In conclusion, supplementing nursing heifers via creep-feeding for 50 days altered physiological and biochemical variables suggestive of a metabolic imprinting effect, but did not hasten their puberty attainment.

Potential of the application of epigenetics in animal production

Our many current environmental challenges, including worldwide abnormal weather, global warming, and pollution, necessitate a new and innovative strategy for animal production for the next generation. This strategy should incorporate not only higher-efficiency production, but also advanced biological concepts and multi-functional agricultural techniques, into environmentally friendly systems. Recent research has discovered a unique phenomenon referred to as ‘foetal and neonatal programming’, which is based on ‘the developmental origins of health and disease (DOHaD)’ concept. These studies have shown that alterations in foetal and early postnatal nutrition and endocrine status may result in developmental adaptations that permanently change the structure, physiology and metabolism of affected animals during adult life. Ruminants fill an important ecological niche that capitalises on the symbiotic relationship between fibre-fermenting ruminal microbes and the mammalian demand for usable nutrients. The timing of the perturbation in maternal nutrient availability plays an important role in determining the effect that the foetal and neonatal programming will have on the developing placenta or foetus and offspring performance. Developmental programming through nutritional manipulations may help the ruminant, as an effective grass–protein converter, fulfil its production potential.