Productive performance,meat quality and fatty acid profile of steers finished in confinement or supplemented at pasture

Thirty Aberdeen Angus crossbred steers (281±16 kg) were used to test the effect of finishing feeding system on growth performance, meat quality and fatty acid (FA) profile in intramuscular fat. Steers were fed in confinement (forage:concentrate ratio of 50 : 50; DM basis) or with different levels of energy supplementation (0, 0.4, 0.8 and 1.2% BW) at pasture (Avena strigosa Schreb and Lolium multiflorum L.). There were no differences between treatments for ADG (average=1.60 kg/day), hot carcass weight (HCW) (average=229 kg) and subcutaneous fat depth (average=3 mm). Dressing % (P=0.06; tendency) and carcass ADG (P=0.02) linearly increased with level of supplementation for pasture steers. No differences were observed between treatments for tenderness, marbling, pH, color b*, or cooking loss and drip loss in samples of Longissimus dorsi. However L* increased linearly (P=0.05) with level of supplementation. The concentrations of myristic, palmitic, estearic and linoleic FA did not differ among treatments. The concentration of n-3 FA increased (P<0.001) in steers at pasture compared with confinement, but n-6 FA concentrations did not differ between feeding system. Supplementation up to 0.4% BW increase (P<0.001) conjugated linoleic acid (CLA) and linolenic FA concentrations in intramuscular fat when compared with confinement. The level of supplementation on pasture linearly decreased (P<0.001) n-3 and CLA and linearly increased (P=0.001) the n-6 : n-3 ratio. Finishing of steers grazing winter pasture with energy supplementation or in confinement fed a medium-concentrate diet did not affect meat quality (tenderness, marbling, parameter b* on the CIE L*a*b* scale, cooking and drip losses) except for a* and L*. However, intramuscular fat of animals finished at pasture with moderate level of supplementation compared to animals fed in confinement had greater concentration of CLA, linolenic, and n-3, and lower n-6 : n-3 in intramuscular fat.     

Growth performance, carcass characteristics and bioavailability of isoflavones in pigs fed soy bean based diets

A growth trial with 38 weaners (castrated male pigs) was designed to compare the growth performance and carcass quality of pigs fed diets containing either soy bean meal or soy protein concentrate in a pair-feeding design. Soy bean meal (SBM) and soy protein concentrate (SPC) differed in isoflavone (daidzein plus genistein) content (782 microg/g in SBM and 125 microg/g in SPC, respectively). During the experiment, all pigs were fed four-phases-diets characterized by decreasing protein concentrations with increasing age (weaner I, weaner II, grower, finisher diets). Rations of control and experimental groups were isoenergetic, isonitrogenous, and isoaminogen. The weanling pigs with an initial live weight of 8.4 +/- 1.1 kg were allotted to flat deck boxes. During the growing/finishing period (days 70-170 of age), the pigs were housed in single boxes. Both, the weaning and the grower/finishing performances (daily body weight gain, feed intake, feed conversion ratio) were similar in both groups. No differences were found between the groups in carcass composition (percentages of cuts, tissues, and protein/fat), and meat quality of pigs. Moreover, the IGF-1R mRNA expression in longissimus muscle was not influenced by the kind of soy product. However, circulating levels of isoflavones were clearly different between pigs fed SBM (genistein 239 +/- 44; daidzein 162 +/- 42; equol 12 +/- 4 ng/ml plasma) and animals fed SPC (genistein 22 +/- 9 and daidzein 8 +/- 3, and equol 10 +/- 3 ng/ml plasma). The results confirm the expected differences in the bioavailability of soy isoflavones, yet, there were no significant differences in performance of pigs fed either soy bean meal or soy protein concentrate.     

Effect of feeding a low-vitamin A diet on carcass and production characteristics of steers with a high or low propensity for marbling

Our research group demonstrated that vitamin A restriction affected meat quality of Angus cross and Simmental steers. Therefore, the aim of this study is to highlight the genotype variations in response to dietary vitamin A levels. Commercial Angus and Simmental steers (n = 32 per breed; initial BW = 337.2 ± 5.9 kg; ~8 months of age) were fed a low-vitamin A (LVA) (1017 IU/kg DM) backgrounding diet for 95 days to reduce hepatic vitamin A stores. During finishing, steers were randomly assigned to treatments in a 2 × 2 factorial arrangement of genotype × dietary vitamin A concentration. The LVA treatment was a finishing diet with no supplemental vitamin A (723 IU vitamin A/kg DM); the control (CON) was the LVA diet plus supplementation with 2200 IU vitamin A/kg DM. Blood samples were collected at three time points throughout the study to analyze serum retinol concentration. At the completion of finishing, steers were slaughtered at a commercial abattoir. Meat characteristics assessed were intramuscular fat concentration, color, Warner-Bratzler shear force, cook loss and pH. Camera image analysis was used for determination of marbling, 12th rib back fat and longissimus muscle area (LMA). The LVA steers had lower (P < 0.001) serum retinol concentration than CON steers. The LVA treatment resulted in greater (P = 0.03) average daily gain than the CON treatment, 1.52 and 1.44 ± 0.03 kg/day, respectively; however, there was no effect of treatment on final BW, DM intake or feed efficiency. Cooking loss and yield grade were greater and LMA was smaller in LVA steers (P < 0.05). There was an interaction between breed and treatment for marbling score (P = 0.01) and percentage of carcasses grading United States Department of Agriculture (USDA) Prime (P = 0.02). For Angus steers, LVA treatment resulted in a 16% greater marbling score than CON (683 and 570 ± 40, respectively) and 27% of LVA Angus steers graded USDA Prime compared with 0% for CON. Conversely, there was no difference in marbling score or USDA Quality Grades between LVA and CON for Simmental steers. In conclusion, feeding a LVA diet during finishing increased marbling in Angus but not in Simmental steers. Reducing the vitamin A level of finishing diets fed to cattle with a high propensity to marble, such as Angus, has the potential to increase economically important traits such as marbling and quality grade without negatively impacting gain : feed or yield grade.     

Growth performance,carcass characteristics and bioavailability of isoflavones in pigs fed soy bean based diets

A growth trial with 38 weaners (castrated male pigs) was designed to compare the growth performance and carcass quality of pigs fed diets containing either soy bean meal or soy protein concentrate in a pair-feeding design. Soy bean meal (SBM) and soy protein concentrate (SPC) differed in isoflavone (daidzein plus genistein) content (782?μg/g in SBM and 125?μg/g in SPC, respectively). During the experiment, all pigs were fed four-phases-diets characterized by decreasing protein concentrations with increasing age (weaner I, weaner II, grower, finisher diets). Rations of control and experimental groups were isoenergetic, isonitrogenous, and isoaminogen. The weanling pigs with an initial live weight of 8.4?±?1.1?kg were allotted to flat deck boxes. During the growing/finishing period (days 70?–?170 of age), the pigs were housed in single boxes. Both, the weaning and the grower/finishing performances (daily body weight gain, feed intake, feed conversion ratio) were similar in both groups. No differences were found between the groups in carcass composition (percentages of cuts, tissues, and protein/fat), and meat quality of pigs. Moreover, the IGF-1R mRNA expression in longissimus muscle was not influenced by the kind of soy product. However, circulating levels of isoflavones were clearly different between pigs fed SBM (genistein 239?±?44; daidzein 162?±?42; equol 12?±?4?ng/ml plasma) and animals fed SPC (genistein 22?±?9 and daidzein 8?±?3, and equol 10?±?3?ng/ml plasma). The results confirm the expected differences in the bioavailability of soy isoflavones, yet, there were no significant differences in performance of pigs fed either soy bean meal or soy protein concentrate.     

Growth performance and carcass traits of steers finished on three different systems including legume–grass pasture and grain diets

Inclusion of legume in grass pastures optimizes protein values of the forage and promotes improved digestibility. Therefore, we hypothesized that finishing steers on a novel combination of legumes and grass pasture would produce carcasses with acceptable traits when compared to carcasses from steers finished in feedlot systems. In this study, we evaluated the effects of finishing steers on three systems including: grazing legume–grass pasture containing oats, ryegrass, white and red clover (PAST), grazing PAST plus supplementation with whole corn grain (14 g/kg BW (SUPP)), and on a feedlot-confined system with concentrate only (28 g/kg BW, consisting of 850 g/kg of whole corn grain and 150 g/kg of protein–mineral–vitamin supplement (GRAIN)) on growth performance of steers, carcass traits and digestive disorders. Eighteen steers were randomly assigned to one of three dietary treatments and finished for 91 days. Data regarding pasture and growth performance were collected during three different periods (0 to 28, 29 to 56 and 57 to 91 days). Subsequently, steers were harvested to evaluate carcass traits, presence of rumenitis, abomasitis and liver abscesses. The legume–grass pasture provided more than 19% dry matter of protein. In addition, pasture of paddocks where steers were assigned to SUPP and PAST treatments showed similar nutritional quality. When compared to PAST, finishing on SUPP increased total weight gain per hectare, stocking rate, daily and total weight gains. The increase of weight gain was high to GRAIN than SUPP and PAST. Steers finished on GRAIN had high hot carcass weight, fat thickness and marbling score when compared to PAST. However, these attributes did not differ between GRAIN and SUPP. Abomasum lesions were more prevalent in steers finished on GRAIN when compared to PAST. Results of this research showed that it is possible to produce carcasses with desirable market weight and fat thickness by finishing steers on legume–grass pasture containing oats, ryegrass, white and red clover. Moreover, supplementing steers with corn when grazing on legume–grass pasture produced similar carcass traits when compared to beef fed corn only.     

AGHR polymorphism and its associations with carcass traits in Harrwoo cattle

The growth hormone receptor (GHR) is a membrane transmitter for the growth hormone signal transduction pathway that regulates various metabolic activities, including cell growth and expressions of cytokine genes. The presence or absence of a genetic polymorphism for the LINE-1 retroposon in the PI promoter, which specifically regulates theGHR gene expression in the liver, was screened by a novel detection method and examined for its relationships with carcass traits in Hanwoo cattle. Han woo cattle had taurine type LINE-1 present (alleleI) as well as incidine type LINE-1 absent (alleleA) promoter sequences. Three genotypes,I/I, I/A andA/A, showed frequencies of 49.1, 36.7 and 14.2%, respectively. The effects of allele A were significant on mean differences for final weight, eye muscle area, marbling score and fat color (p<0.05), but not for carcass weight, backfat thickness, final meat quality grade or meat color (p>0.05). Most 30-month old Hanwoo steers bearing the LINE-1 absent promoter had whiter fat color, heavier live weight and higher marbling score, reflecting intramuscular fat deposition inM. longissimus dorsi, compared to animals bearing a LINE-1 present promoter. This suggests that aGHR polymorphism could be a potential genetic marker for improving beef production of Hanwoo cattle.     

Effects of whole linseed supplementation and treatment duration on fatty acid profile and endogenous bioactive compounds of beef muscle

Diet supplementation with oilseeds is known to improve the fatty acid profile of meat, but few studies have been carried out to determine the time required for the incorporation of a significant quantity of n-3 polyunsaturated fatty acids (PUFA) into meat from steers. Therefore, the present study aimed to assess the effects of linseed supplementation and feeding duration on the fatty acid profile, cholesterol and bioactive compounds of bovine meat. In total, 54 Friesian steers were randomly allocated during the finishing period into six experimental treatments following a 2×3 factorial design. The six treatments consisted of two diets, the control diet (CO) with no supplemental fat and the linseed diet (LS) containing 10% whole linseed, fed 40, 75 or 120 days before slaughter. At the end of each finishing period, steers from the CO and LS groups were slaughtered. After 8 days of ageing chemical analysis, the fatty acid profile, cholesterol content and bioactive compounds were determined from the longissimus thoracis muscle. Including linseed in the diet increased the content of monounsaturated fatty acids, CLA and n-3 PUFA, and reduced the proportion of saturated fatty acids and n-6 PUFA. The percentage of myristic fatty acid increased with the duration of feeding, regardless of diet and a decrease in PUFA and n-6 PUFA was observed in the CO and LS diets, respectively. Furthermore, meat from steers fed linseed showed an increased percentage of n-3 PUFA, linolenic acid, and EPA from 40 to 75 days of feeding, whereas vaccenic acid, CLA 9c,11t, and total CLA increased from 40 and 75 days but declined at 120 days. Beef from the linseed group had a higher content of bioactive substances such as creatine, carnosine and anserine than beef from the control group. The duration of feeding significantly affected the creatine concentrations, with an increase in the LS group from 40 to 75 days of feeding. Feeding linseed did not modify the cholesterol content, on average and the lowest cholesterol content was found in meat after 75 days of linseed administration. This study demonstrates that a short-term diet manipulation is sufficient to improve the nutritional properties of meat, including n-3 PUFA and bioactive compounds.     

Effects of castration and time-on-feed on Mertolenga breed beef quality

Physicochemical characteristics were determined in the longissimus lumborum muscle, after 8 days of ageing of steers (n=12) and bulls (n=12) from Mertolenga breed slaughtered directly from pasture (day 0) or after a finishing period of 50, 100 and 150 days in a feed-lot facility. Bulls and steers presented similar live weight (averaging 388 kg), carcass weight (CW; averaging 213 kg), dressing percentage (averaging 60%), carcass fatness (11.9% CW) and carcass fat thickness (averaging 3.03 mm). Live weight, CW, carcass fatness and fat thickness increased along time-on-feed. Gender only had a negligible effect on meat characteristics, with b* and h* being the only parameters of colour affected by gender, also presenting a significant interaction gender×time-on-feed. Nevertheless, both the genders presented a high-quality grade concerning tenderness (Warner–Bratzler shear force (WBSF)). L* increased until 50 days on feed and decreased afterwards, whereas a* and C* values increased along time-on-feed. Pigment content was also affected by time-on-feed and showed a gender×time-on-feed interaction. Beef colour became darker and redder along time-on-feed, but still in a colour range highly acceptable by Portuguese consumers. Despite the increase in intramuscular fat and myofibrillar fragmentation index, as well as the decrease in collagen content of steers and bulls along time-on-feed, it did not affect the tenderness/hardness, indicating a small effect of time-on-feed in meat characteristics. Despite only small differences in carcass characteristics and meat-quality parameters that have been noticed along time-on-feed, those differences were only significant after 100 days on feed. Principal component analysis (PCA) was performed. The first PC axis (39.6% of the total variance) included colour variables a*, b* and C*, and carcass fatness, fat thickness, CW and live weight, whereas the second one (12.7% of the total variance) included h*, cooking losses and dressing-out. The principal component (PC) analysis confirmed the lack of differences between bulls and steers and indicates a differentiation of the first two periods of feeding (0 and 50 days on feed) from the two latter (100 and 150 days on feed) periods of feeding.     

Blood profile and meat quality of Holstein-Friesian steers finished on total mixed ration or flaxseed oil-supplemented pellet mixed with reed canary grass haylage

Holstein-Friesian steer beef production is renowned globally as a secondary product of the milk industry. Grass feeding is a common practice in raising Holstein steers because of its low cost. Furthermore, grass feeding is an alternative way to produce beef with a balanced n-6 to n-3 fatty acids (FAs) ratio. However, the performance and meat quality of Holstein-Friesian cattle is more likely to depend on a high-quality diet. The aim of this study was to observe whether feeding two mixed diets; a corn-based total mixed ration (TMR) with winter ryegrass (Lolium perenne) or flaxseed oil-supplemented pellets with reed canary grass haylage (n-3 mix) provided benefits on carcass weight, meat quality and FA composition compared with cattle fed with reed canary grass (Phalaris arundinacea) haylage alone. In all, 15 21-month-old Holstein-Friesian steers were randomly assigned to three group pens, were allowed free access to water and were fed different experimental diets for 150 days. Blood samples were taken a week before slaughter. Carcass weight and meat quality were evaluated after slaughter. Plasma lipid levels and aspartate aminotransferase (AST), γ-glutamyl transpeptidase (GGT), creatine kinase (CK) and alkaline phosphatase (ALP) activities were determined. Diet did not affect plasma triglyceride levels and GGT activity. Plasma cholesterol levels, including low-density and high-density lipoproteins, were higher in both mixed-diet groups than in the haylae group. The highest activities of plasma AST, CK and ALP were observed in the haylage group, followed by n-3 mix and TMR groups, respectively. Carcass weight was lower in the haylage group than in the other groups and no differences were found between the TMR and n-3 mix groups. Although the n-3 mix-fed and haylage-fed beef provided lower n-6 to n-3 FAs ratio than TMR-fed beef, the roasted beef obtained from the TMR group was more acceptable with better overall meat physicochemical properties and sensory scores. According to daily cost, carcass weight and n-6 to n-3 FAs ratio, the finishing diet containing flaxseed oil-supplemented pellets and reed canary grass haylage at the as-fed ratio of 40 : 60 could be beneficial for the production of n-3-enriched beef.     

Carcass and meat quality of finished and non-finished Limousin heifers from alpine livestock systems differing in altitudinal origin of the forage

Effects of the alpine origin of the forage and of finishing on carcass and beef quality were quantified by modelling different alpine livestock system alternatives. Thirty-five Limousin heifers, initially weighing 383 ± 45 kg, were fed fresh grass at 400 or 2000 m above sea level, or a 1:1 mixture of alpine grass and lowland grass hay at 2000 m. After 9 weeks, the six heaviest and oldest animals per group were slaughtered. The remaining animals were finished for 8 weeks on a silage-concentrate diet in the lowlands to similar age and body weight as the first slaughtered group. Carcass and meat quality (M. longissimus thoracis) were assessed in various respects. The average daily gains achieved were of about 600 g/d and similar between forage-type groups. Dressing percentage was 53.5% in the alpine and 57.2% in the lowland group. Carcass conformation and fat cover scores did not differ between forage-type groups. The meat from the alpine groups had greater ultimate pH and smaller redness, yellowness and protein contents. Still, these differences were of minor practical relevance. There was no forage-type effect on water-holding capacity and shear force of the meat. The alpine systems enhanced the proportion of α-linolenic acid in intramuscular fat and decreased the levels of some volatile compounds in perirenal fat. Finishing resulted in compensatory growth, especially in the animals previously fed lowland grass. There was a trend for the finished compared with the non-finished groups towards greater carcass fat cover and intramuscular fat content. Additionally, ultimate pH was smaller and cooking loss was greater with than without finishing. Meat colour differences were also observed. Shear force was not affected by finishing. The finished animals had a smaller α-linolenic acid proportion in the intramuscular fat. In conclusion, the forage type had small effects on carcass and meat quality. Finishing did not substantially improve carcass and meat quality. The (alpine) grass-specific differences in fatty acid profile found in the unfinished cattle were not present in the finished animals.     

Effect of feeding food waste-broiler litter and bakery by-product mixture to pigs

This study was conducted to evaluate the effects of feeding aerobically processed and vacuum-dried food waste-broiler litter and bakery by-product mixture to finishing pigs on performance, carcass characteristics, meat quality and taste panel test. A corn-soy diet (Control) was replaced with food waste mixture (FWM) at dietary levels of 25% (25% FWM) and 50% (50% FWM) on a dry matter (DM) basis. Diets were fed to a total of 45 pigs (mean body weight 69.4kg) during the eight wk of finishing period. After slaughtering, longissmus muscle at 24h postmortem was used for meat quality analysis. Restaurant food waste was high in protein (22.0%) and fat (23.9%). Supplementing a corn-soy diet with FWM increased (P<0.05) feed DM intake, did not alter (P>0.05) average daily gain, decreased (P<0.05) feed efficiency especially for 50% FWM treatment, and substantially reduced (P<0.05) feed cost, compared with feeding a corn-soy diet only. Feeding FWM up to 50% did not affect (P>0.05) carcass characteristics (carcass weight, dressing percentage, backfat thickness and carcass grade), meat fatty acid composition, meat quality (marbling score, pH, water holding capacity, drip loss, L*, a*, b* values, Warner-Bratzler shear force, cooking loss), and taste panel test (flavor, taste, tenderness, juiciness, and overall acceptance) compared with feeding a corn-soy diet. However, meat color was paler (P<0.05) for 50% FWM fed animals than a corn-soy diet fed animals. Meat color was the only limiting factor when FWM was fed to finishing pigs. In conclusion, aerobically processed and vacuum-dried food waste-broiler litter and bakery by-product mixture was similar to a corn-soy diet in feed value for finishing pigs.     

Effects of carcass maturity on meat quality characteristics of beef semitendinosus muscle for chinese native yellow steers

This work was designed to study the effects of carcass maturity on meat quality characteristics and intramuscular connective tissue of beef semitendinosus muscle from Chinese native Yellow steers. Chemical determinations, histological and mechanical measurements were performed on the raw and cooked meat at 4 days post mortem. In raw meat, intramuscular fat, collagen solubility, mechanical strength and transition temperature of intramuscular connective tissue increased (P < 0.05) with carcass maturity before body maturation, whilst moisture, total collagen, fibre diameter decreased after body maturation. Warner-Bratzlar shear force (WBSF) of cooked meat increased with maturity before body maturation due to the muscle atrophy, and thus the decline of moisture content and the increase of cooking losses. After body maturation, the increase of WBSF was neutralised by the increase of intramuscular fat, the decrease of total collagen and the elongation of sarcomere length.     

Association of the leptin gene E2-169T > C and E3-299T > A mutations with carcass and meat quality traits of the Chinese Simmental-cross steers

Leptin is a hormone affecting the regulation of body composition, energy balance, and meat quality in mammals. The objective of this study was to evaluate the association of novel single nucleotide polymorphisms in coding region for leptin gene with carcass and meat quality traits of Chinese Simmental-cross steers. Two SNPs (E2-169 T > C and E3-299 T > A) were genotyped on 135 crossbred bulls. The 45 traits being measured included dressing percentage, dressed weight, marbling score, muscle color score, backfat thickness, fatty acid content, etc. Statistical analysis revealed that two SNPs in the exon of leptin gene were associated with the carcass and meat quality traits. The C-bearing genotypes (CC or TC) of E2-169 T > C (C57R) showed higher dressed weight, thickness of loin, MCS, FCS, intramuscular fat content, and polyunsaturated fatty acid content (P < 0.05). E3-299  > A(S100T) also showed a significant association with the carcass traits (dressing percentage, living QIB) and fatty acid content in Simmental-cross steers(P < 0.05). Our findings suggested that polymorphisms in leptin might be one of the important genetic factors that influence carcass yield and meat quality in beef cattle, and it may be a useful marker for meat quality traits in future marker-assisted selection programs in beef cattle breeding and production.     

Effects of genomic estimated breeding value and dietary energy to protein ratio on growth performance,carcass trait,and lipogenic gene expression in Hanwoo steer

“Genome-based precision feeding” is a concept that involves the application of customised diets to different genetic groups of cattle. We investigated the effects of the genomic estimated breeding value (gEBV) and dietary energy to protein ratio (DEP) on growth performance, carcass traits, and lipogenic gene expression in Hanwoo (Korean cattle) steers. Forty-four Hanwoo steers (BW = 636 kg, age = 26.9 months) were genotyped using the Illumina Bovine 50 K BeadChip. The gEBV was calculated using genomic best linear unbiased prediction. Animals were separated into high gEBV of marbling score or low-gMS groups based on the upper and lower 50% groupings of the reference population, respectively. Animals were assigned to one of four groups in a 2 × 2 factorial arrangement: high gMS/high DEP (0.084 MJ/g), high gMS/low DEP (0.079 MJ/g), low gMS/high DEP, and low gMS/low DEP. Steers were fed concentrate with a high or low DEP for 31 weeks. The BW tended to be higher (0.05 < P < 0.1) in the high-gMS groups compared to the low-gMS groups at 0, 4, 8, 12, and 20 weeks. The average daily gain (ADG) tended to be lower (P = 0.08) in the high-gMS group than in the low-gMS group. Final BW and measured carcass weight (CW) were positively correlated with the gEBV of carcass weight (gCW). The DEP did not affect ADG. Neither the gMS nor the DEP affected the MS and beef quality grade. The intramuscular fat (IMF) content in the longissimus thoracis (LT) tended to be higher (P = 0.08) in the high-gMS groups than in the low-gMS groups. The mRNA levels of lipogenic acetyl-CoA carboxylase and fatty acid binding protein 4 genes in the LT were higher (P < 0.05) in the high-gMS group than in the low-gMS group. Overall, the IMF content tended to be affected by the gMS, and the genetic potential (i.e., gMS) was associated with the functional activity of lipogenic gene expression. The gCW was associated with the measured BW and CW. The results demonstrated that the gMS and the gCW may be used as early prediction indexes for meat quality and growth potential of beef cattle.     

Feeding dried distillers grains with solubles to lactating beef cows: impact of excess protein and fat on post-weaning progeny growth,glucose tolerance and carcass traits

Feeding dried distillers grains with solubles (DDGS), a feed high in fat and protein, to lactating beef cows can alter milk production and composition, resulting in improved pre-weaning growth of progeny. This alteration in milk profile may consequently alter the growth and carcass composition of the offspring after weaning. Therefore, Angus×Simmental steers (n=48) whose dams were fed one of two diets supplemented with either DDGS or soybean meal (CON) from calving to mid-lactation were placed in a feedlot to determine the effects of maternal nutrition during lactation on progeny development and carcass composition. Cow–calf pairs were allotted to two treatments at birth based on cow and calf BW, breed and age. Maternal diets were isocaloric (3.97 MJ/kg NE_g) and consisted of rye hay supplemented with DDGS at 1% of BW (19.4% CP; 8.76% fat) or rye hay and corn silage supplemented with CON (11.7% CP; 2.06% fat). After conclusion of the treatments at 129 days postpartum, cow–calf pairs were comingled and managed as one group until weaning at 219 days postpartum. Steers were then transitioned to a common diet composed of 60% DDGS, 34% corn silage and 6% vitamin/mineral supplement and were placed indoors in individual pens with slatted floors. An intravenous glucose tolerance test (IVGTT) was performed 134 days after feedlot entry on 16 steers (CON, n=7; DDGS, n=9) to determine the effect of maternal diet on glucose and insulin sensitivity. Steers were slaughtered at a target BW of 645 kg. Categorical and continuous data were analyzed using the GLIMMIX and MIXED procedures of SAS, respectively. Steers from DDGS dams tended to be heavier on day 85 of feedlot finishing (P=0.09) compared with steers from CON dams. However, there were no differences in final weight, average daily gain, dry matter intake or efficiency (gain:feed, P⩾0.18). Maternal treatments did not affect progeny days on feed (P=0.15), despite a mean difference of 9 days in favor of DDGS. Glucose and insulin concentrations and area under the curve of progeny as measured by IVGTT were not affected by maternal diet (P⩾0.16). Maternal DDGS supplementation decreased marbling score (P=0.04), but did not influence carcass grading percentage or any other carcass characteristic (P⩾0.17).     

Inclusion of sunflower seed and wheat dried distillers’ grains with solubles in a red clover silage-based diet enhances steers performance,meat quality and fatty acid profiles

The current study compared beef production, quality and fatty acid (FA) profiles of yearling steers fed a control diet containing 70 : 30 red clover silage (RCS) : barley-based concentrate, a diet containing 11% sunflower seed (SS) substituted for barley, and diets containing SS with15% or 30% wheat dried distillers’ grain with solubles (DDGS). Additions of DDGS were balanced by reductions in RCS and SS to maintain crude fat levels in diets. A total of two pens of eight animals were fed per diet for an average period of 208 days. Relative to the control diet, feeding the SS diet increased (P<0.05) average daily gain, final live weight and proportions of total n-6 FA, non-conjugated 18:2 biohydrogenation products (i.e. atypical dienes) with the first double bond at carbon 8 or 9 from the carboxyl end, conjugated linoleic acid isomers with the first double bond from carbon 7 to 10 from the carboxyl end, t-18:1 isomers, and reduced (P<0.05) the proportions of total n-3 FA, conjugated linolenic acids, branched-chain FA, odd-chain FA and 16:0. Feeding DDGS-15 and DDGS-30 diets v. the SS diet further increased (P<0.05) average daily gains, final live weight, carcass weight, hot dressing percentage, fat thickness, rib-eye muscle area, and improved instrumental and sensory panel meat tenderness. However, in general feeding DGGS-15 or DDGS-30 diets did not change FA proportions relative to feeding the SS diet. Overall, adding SS to a RCS-based diet enhanced muscle proportions of 18:2n-6 biohydrogenation products, and further substitutions of DDGS in the diet improved beef production, and quality while maintaining proportions of potentially functional bioactive FA including vaccenic and rumenic acids.     

Performance,profitability and greenhouse gas emissions of alternative finishing strategies for Holstein-Friesian bulls and steers

Modifying finishing strategies within established production systems has the potential to increase beef output and farm profit while reducing greenhouse gas (GHG) emissions. Thus, the objectives of this study were to investigate the effects of finishing duration on animal performance of Holstein-Friesian (HF) bulls and steers and evaluate the profitability and GHG emissions of these finishing strategies. A total of 90 HF calves were assigned to a complete randomised block design; three bull and three steer finishing strategies. Calves were rotationally grazed in a paddock system for the first season at pasture, housed and offered grass silage ad libitum plus 1.5 kg DM of concentrate per head daily for the first winter and returned to pasture for a second season. Bulls were slaughtered at 19 months of age and either finished indoors on concentrates ad libitum for 100 days (19AL), finished at pasture supplemented with 5 kg DM of concentrate per head daily for 100 (19SP) or 150 days (19LP). Steers were slaughtered at 21 months of age and finished at pasture, supplemented with 5 kg DM of concentrate per head daily for 60 (21SP) and 110 days (21LP) or slaughtered at 24 months of age and finished indoors over the second winter on grass silage ad libitum plus 5 kg DM of concentrate per head daily (24MO). The Grange Dairy Beef Systems Model and the Beef Systems Greenhouse Gas Emissions Model were used to evaluate profitability and GHG emissions, respectively. Average daily gain during the finishing period (P<0.001), live weight at slaughter (P<0.01), carcass weight (P<0.05) and fat score (P<0.001) were greater for 19AL than 19SP and 19LP, respectively. Similarly, concentrate dry matter intake was greater for 19AL than 19SP; 19LP was intermediate (P<0.001). Live weight at slaughter (P<0.001), carcass weight (P<0.001), conformation score (P<0.05) and fat score (P<0.001) were greater for 24MO than 21SP and 21LP, respectively. During the finishing period concentrate dry matter intake was greater for 21LP than 21SP with 24MO intermediate; 542, 283 and 436 kg DM, respectively. Although pasture-based finishing strategies had lower gross output values, concentrate feed costs were also reduced thus net margin was greater than indoor finishing strategies. Reducing concentrate input increased GHG emissions for bulls and steers slaughtered at the same age, respectively. Although prolonging the finishing duration reduced GHG emissions for bull and steer production systems, finishing bulls and steers over a longer period at pasture did not enhance animal performance and profit.     

Improved tenderness of beef from bulls supplemented with active dry yeast is related to matrix metalloproteinases and reduced oxidative stress

Supplementing diets with active dry yeast (ADY, Saccharomyces cerevisiae) improves the carcass quality grade of beef cattle and the tenderness of beef. The relevant mechanisms have not been fully elucidated, but may be related to the effect of ADY on oxidative stress and the activity of matrix metalloproteinases (MMPs). To provide further insight into these mechanisms, this study evaluated the influence of ADY supplementation on growth performance, carcass traits, meat quality, concentrations of MMPs in serum (MMP-2, MMP-9 and MMP-13), oxidative stress indices and antioxidant capacity indices in beef cattle. Forty-six crossbred Simmental × Yanbian bulls (～18 months of age, BW 436 ± 35 kg) participated in a 145-day finishing trial. ADY supplementation significantly improved marbling deposition, intramuscular fat content, and beef tenderness (P < 0.05); altered individual fatty acid proportions in the beef and increased saturated fatty acids while decreasing polyunsaturated fatty acids (P < 0.05); significantly decreased the abundance of reactive oxygen species in serum and meat; significantly increased the level of superoxide dismutase in meat (P < 0.05); tended to increase the level of catalase (P = 0.075) in serum and glutathione reductase (P = 0.066) in meat; and increased the secretion of MMPs. The improvement of beef tenderness following ADY supplementation of finishing bulls is related to the effects of ADY on the secretion of MMPs and the lowering of oxidative stress.     

Effects of supplementation with fish oil and barium selenate on performance, carcass characteristics and muscle fatty acid composition of late season lamb finished on grass-based or concentrate-based diets

The objectives of this study were to investigate the effects of fish oil supplementation on performance and muscle fatty acid composition of hill lambs finished on grass-based or concentrate-based diets, and to examine the interaction with selenium (Se) status. In September 2006, 180 entire male lambs of mixed breeds were sourced from six hill farms after weaning and finished on five dietary treatments: grazed grass (GG), grass +0.4 kg/day cereal-based concentrate (GC), grass +0.4 kg/day cereal-based concentrate enriched with fish oil (GF), ad libitum cereal-based concentrate (HC) and ad libitum fish oil-enriched concentrate (HF). Within each treatment, half of the lambs were also supplemented with barium selenate by subcutaneous injection. At the start of the trial, the proportion of lambs with a marginal (<0.76 μmol/l) or deficient (<0.38 μmol/l) plasma Se status was 0.84 and 0.39, respectively. Compared with control lambs, GG lambs treated with Se had higher (P < 0.01) plasma Se levels, whereas erythrocyte glutathione peroxidase activity was higher (P < 0.01) for Se-supplemented lambs fed diets GG and GF. However, Se supplementation had no effects on any aspect of animal performance. Fish oil increased (P < 0.05) levels of 22:5n-3 and 22:6n-3 in the Longissimus dorsi of HF lambs but otherwise had no effect on the health attributes of lamb meat. There were no significant effects of fish oil on dry matter intake, animal performance or lamb carcass characteristics. Daily carcass weight gain (CWG; P < 0.001), carcass weight (P < 0.01) and conformation score (P < 0.01) increased with increasing concentrate inputs. Lambs fed concentrate-based diets achieved a higher mean CWG (P < 0.001), dressing proportion (P < 0.001) and carcass weight (P < 0.011), and were slaughtered up to 8.3 days earlier (P < 0.05) and at 1.2 kg lower (P < 0.05) live weight than pasture-fed lambs. However, carcasses from grass-fed lambs contained lower levels of perinephric and retroperitoneal fat (P < 0.05), and had less fat over the Iliocostalis thoracis (P < 0.001) and Obliquus internus abdominis (P < 0.05). Meat from grass-fed lambs also had lower levels of 18:2n-6 and total n-6 fatty acids compared with those finished indoors. The results of this study demonstrate that fish oil supplementation has some benefits for the health attributes of meat from lambs fed concentrate-based diets but not grass-based diets. Supplementing Se-deficient lambs with barium selenate will improve Se status of lambs fed zero-concentrate diets, but has no additional benefit when lambs are already consuming their daily Se requirement from concentrates or when fish oil-enriched diets are fed.