Effects of days on feed,roughage sources and inclusion levels of grain in concentrate on finishing performance and carcass characteristics in cull beef cows

An experiment was conducted with 16 Japanese Black cows to determine the effects of different days on feed (89, 208, 271 and 341 days), inclusion levels of grain in concentrate (60% vs. 40%; dry matter (DM) basis) and roughage sources (hay vs. rice straw) on finishing performance. Additional four cows were slaughtered at 0 days on feed to obtain non‐fed carcass data. Maximum carcass weights were observed in cows fed for 271 days; an increase in carcass weight of only 14 kg was shown from 208 days to 271 days. The marbling score increased (P < 0.05) with days on feed. The percentage of fat in the subprimal rib linearly increased (P < 0.05) with days on feed. The percentage of lean meat was higher (P < 0.05) for cows fed rice straw than for cows fed hay as a roughage source. Increasing the days on feed decreased (P < 0.05) the yellowness of the fat. The effects of the inclusion levels of grain in concentrate on the finishing performance of cows were lower than the other two factors. In conclusion, feeding improves carcass values, but feeding over 208 days is an inefficient system of production in cows.     

The effects of feeding a low level of distiller's dried grains with solubles (DDGS) to yearling Holstein steers

We examined the effects of feeding a low percentage of distiller's dried grains with solubles (DDGS) to yearling Holstein beef steers during the late stage of the fattening period on growth performance and carcass quality. Fifteen animals were fed a total mixed ration (TMR) feed plus a DDGS supplement equal to 10% of the total feed weight for 3 months (DDGS group). The other 15 animals were fed TMR with no DDGS (Control group). The vitamin E (VE) levels in the blood from the DDGS group showed a tendency to be higher in the DDGS group (P = 0.056). Blood urea nitrogen levels in the DDGS group were also higher (P < 0.05). The Beef Color Standard (BCS) number for the DDGS group was also higher than that for the Control group (P < 0.05). Forty‐eight hours after cutting, the yellowness (b*) value for Longissimus muscle in the DDGS group was significantly higher (P < 0.05) and the redness (a*) value in the DDGS group tended to be higher than that in the Control group (P = 0.05). The study results show a potential for adding value to yearling beef by improving the ability to maintain meat color with an increase in VE content.     

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.     

Genetic effects on fatty acid composition of carcass fat of Japanese Black Wagyu steers

Two hundred ninety-three Japanese Black Wagyu steers derived from 34 sires were used to investigate genetic effects on the fatty acid composition of carcass fat. All steers were fed identical diets for 365 d and slaughtered at similar ages. If the percentage of genetic contribution of sire A, B, or C was not lower than 25%, steers were classified into groups A, B, and C, respectively. Fatty acid compositions differed depending on deposit sites. Mean percentage of monounsaturated fatty acids (MUFA) tended to be higher in the outer parts than in the inner parts of the body. Percentage of MUFA in carcass fat was negatively correlated with withers height and BW and positively correlated with meat quality score and marbling score. Fatty acid compositions of the 34 sire groups varied, and mean percentages of MUFA in i.m. fat ranged from 47.71 to 54.77%. Steers in the C group grew larger than those in the A or B group. Mean percentages of MUFA for i.m. fat in the A, B, and C groups (52.83, 51.88, and 50.33%, respectively) differed (P < 0.05) from each other. Steers in the C group had higher (P < 0.05) percentages of saturated fatty acids than those in the A or B groups. Percentages of genetic contribution of sires B (P < 0.05) and C (P < 0.001) were negatively correlated with percentage of MUFA in i.m. fat. These results suggested that genetic factors affected fatty acid composition of carcass fat in Japanese Black Wagyu cattle and that some sires had potent genetic factors affecting this composition.     

Effect of health status on fattening performance in young crossbred polish Holstein‐Friesian × Limousin Bulls and steers

The aim of this study was to determine the effect of disease incidence on selected parameters of cattle fattening performance and carcass quality, and the fatty acid profile of beef. The experimental materials comprised 16 bulls and 16 steers, Polish Holstein‐Friesian × Limousin crossbreeds (including 10 healthy and six treated animals of each category). At 5 weeks of age, bloodless castration was carried out using a rubber elastrator. The calves were fed milk replacer provided in automatic feeding stations. Until 540 days of age, the animals were fattened in an Animal Research Laboratory equipped with the Roughage Intake Control (RIC) system (Insentec, the Netherlands). In comparison with healthy (untreated) bulls and steers, sick (treated) animals had lower average body weight at 180 days of age, by 37 kg (P ≤ 0.05) and lower average final body weight at 540 days of age, by 56 kg (P ≤ 0.05). Sick animals were characterized by lower feed intake and worse feed efficiency (not statistically significant differences). Hot carcass weight reached 318 kg in healthy animals and 258 kg in treated bulls (P ≤ 0.05). In treated steers, the percentage of lean meat and bones in the three‐rib section was higher and the percentage of fat was lower, compared with their healthy counterparts (P ≤ 0.01). There was a category × health status interaction for carcass tissue composition. There were no significant influences of type of sickness on analyzed traits. In comparison with healthy steers, intramuscular fat of Musculus longissimus dorsi (MLD) from treated steers had significantly (P ≤ 0.05) higher concentrations of polyunsaturated fatty acids (n‐6 and n‐3) and a lower content of conjugated linoleic acid.     

The effects of grazing and supplemental protein concentrations during the grazing period on subsequent finishing performance and carcass quality in Japanese Black cattle steers

The effects of grazing and supplemental protein concentrations, provided during the grazing period, on subsequent finishing performance and carcass quality were investigated. This experiment was carried out using 15 Japanese Black cattle (Wagyu) steers. The steers were fed as follows: (i) grazing supplemented with moderate protein concentrate (GMP) (18% crude protein (CP); dry matter (DM) basis) before finishing, followed by feeding in a barn until slaughter; (ii) grazing supplemented with low protein concentrate (GLP) (14% CP; DM basis) before finishing, followed by feeding in the barn until slaughter; and (iii) no grazing before finishing (NG). From the end of the grazing season to the end of the growing period, the GMP and GLP steers were managed in the same way as the NG steers. All of the animals were fed the same diet in the finishing period (9 months to 28 months). None of the three treatments affected the average daily gains. For all treatments, chilled carcass weights were more than 450 kg and did not differ significantly among the groups. The longissimus muscle areas in the grazed steers were numerically larger than in those receiving the NG treatment. Fat thickness was significantly greater (P < 0.05) in the NG steers than in the grazed steers. The intramuscular fat and marbling scores were not affected in the grazed steers. In conclusion, the carcass quality of grazed steers was similar to that of the NG steers at a similar final age, and the quantity of meat in the NG steers would be less than that of the GMP and GLP steers. Therefore, spring‐born Wagyu steers should be grazed using the GLP supplement before fattening.     

Growth performance,carcass traits,physiochemical characteristics and intramuscular fatty acid composition of finishing Japanese black steers fed soybean curd residue and soy sauce cake

This study was conducted to determine the effects of dietary soybean curd residue (SCR) and soy sauce cake (SSC) on the growth performance, carcass traits and physiochemical and intramuscular fatty acid (FA) characteristics in Japanese Black steers. Ten steers (29.7 ± 0.3 months old, 856.6 ± 24.4 kg body weight) were assigned to either treatment C, fed a conventional concentrate or T, fed the test diet including dried SCR and SSC for 3 months. In growth performance, dry matter (DM) intake and average daily gain, and carcass traits did not differ significantly between the treatments. Color of beef was affected by the dietary treatments and meat samples from T showed higher a^* value and chroma than those in C. On FA composition, there was no significant difference between the treatments in neutral lipids, whereas in polar lipids, meat samples from T had higher C16:1 (P < 0.05) and tended to have higher C16:0 (P = 0.05) and C18:1 (P = 0.08), but lower C17:0 (P = 0.098), C18:2 (P = 0.06) and C20:4 (P = 0.07) than those from C. The study suggested that SCR and SSC could be used as a substitute for conventional concentrate and would influence meat color and intramuscular FA composition of polar lipids.     

Fat depot‐specific differences in leptin mRNA expression and its relation to adipocyte size in steers

ABSTRACT This experiment was conducted to investigate leptin mRNA expression, adipocyte size, and their relationship in several adipose tissues of fattening steers. Subcutaneous, perirenal, intermuscular and intramuscular adipose tissues were collected from three crossbred steers (Japanese Black cattle X Holstein) aged 21 months. The mRNA level and adipocyte diameter were determined in these adipose tissues. The intramuscular adipose tissue had a lower leptin mRNA level than the intermuscular and perirenal adipose tissues (P < 0.05). Leptin mRNA level was lower in the subcutaneous depot than in the intermuscular depot (P < 0.05). Adipocyte diameter was larger in the intermuscular adipose tissue than in the subcutaneous and intramuscular adipose tissues (P < 0.05). Leptin mRNA level was positively correlated with adipocyte diameter (r² = 0.81, P < 0.05). These results suggest that the cattle have fat depot‐specific differences in leptin gene expression, which are a result of a difference in adipocyte size.     

Variations in genes involved in fat metabolism and their association with ultrasonic and carcass traits in Japanese Black steers

Polymorphisms in genes involved in lipid metabolism have been reported to be associated with fatty acid composition of adipose tissue. However, the relationship of these polymorphisms with premortem ultrasonic traits is unknown. The objective of this study, therefore, was to assess the association between polymorphisms in fatty acid synthase, stearoyl‐coenzyme A desaturase (SCD), sterol regulatory element‐binding protein 1 (SREBP1), diacylglycerol acyltransferase 1, and nuclear receptor subfamily 1, group H, number 3 genes with ultrasonic and carcass traits in Japanese Black steers (n = 300) under progeny testing at the Livestock Improvement Association of Miyazaki. To have a comprehensive analysis of the association between the aforementioned genetic polymorphisms and ultrasonic traits, longitudinal measurements of ultrasonic traits were taken. Furthermore, the association of these genetic polymorphisms and carcass traits was evaluated. The polymorphisms in the SCD gene and SREBP1 were associated (P < 0.05) with some ultrasonic traits at multiple stages. To add to that, the polymorphisms were associated (P < 0.05) with some carcass traits. These findings suggest that the polymorphisms in SCD and SREBP1 are functional mutations or could be related to mutations that can aid in selection to improve some ultrasonic and carcass traits.     

Genomic imprinting variances of beef carcass traits and physiochemical characteristics in Japanese Black cattle

The objective of this study was to estimate variance components related to imprinting for carcass traits and physiochemical characteristics in Japanese Black cattle. The carcass records obtained from 4,220 Japanese Black feedlot cattle included carcass weight (CW), rib eye area (REA), rib thickness, subcutaneous fat thickness, and beef marbling score (BMS), and the physiochemical characteristics were fat, moisture, glycogen per proportion of moisture content, oleic acid, and monounsaturated fatty acids (MUFA). To detect gametic effects, an imprinting model was fitted. High additive heritabilities were estimated for all traits (from 0.516 for glycogen to 0.853 for fat) and were reduced in Mendelian heritability. The range of the differences was from 0.002 (CW) to 0.331 (fat and moisture), and the reductions were due to their imprinting variances. The ratio of the imprinting variance to the total additive genetic variance for REA (0.374), BMS (0.291), fat (0.387), moisture (0.388), and MUFA (0.337) were large (p < 0.05). These imprinting variances were due to the maternal contribution and suggested the existence of maternally expressed genomic imprinting effects on the traits in Japanese Black cattle. Therefore, maternal gametic effects should be considered in breeding programs for Japanese Black cattle.     

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.     

Effect of feeding wood kraft pulp on the growth performance,feed digestibility,blood components,and rumen fermentation in Japanese Black fattening steers

This study aimed to examine the effects of feeding kraft pulp (KP) on the growth performance, feed digestibility, and rumen fermentation of Japanese Black fattening steers. Ten Japanese Black fattening steers (aged 26 months) were randomly divided into control and KP groups. The control group (n = 5) was fed concentrate feed without KP, and the KP group (n = 5) was fed concentrate feed containing 10% KP. Both the groups were provided rice straw as roughage. The experiment was conducted over a period of 12 weeks. There was no significant difference in dry matter intake, daily body weight gain, and nutrient digestibility between both groups. No difference was observed in the ruminal concentrations of volatile fatty acids among the groups. At weeks 8 and 12 after the onset of the experiment, the acetate‐to‐propionate ratio in the ruminal fluid of the KP group was significantly higher than that of the control group. The average daily pH of ruminal fluid and activity of ruminal lipopolysaccharide did not differ between the groups. Our results suggested that the growth performance and feed digestibility in the Japanese Black fattening steers were not influenced by replacing concentrate feed with KP.     

玉米不同加工方式对肉牛育肥性能的影响

本试验旨在探讨玉米加工利用的适宜方法,以提高玉米的利用效率。选用120头利木赞杂交阉牛(590 kg±10 kg),随机分为4组,分别饲喂蒸汽压片(A)、粉碎后过七目筛(B)、十目筛(C)和十四目筛(D)的玉米型日粮,研究日粮玉米不同加工方法对阉牛育肥性能的影响。结果表明,玉米不同加工方式对肉牛的生产性能和大多数胴体指标都没有显著影响(P＞0.05)。蒸汽压片玉米组的胴体产肉率高于十目筛组,骨重低于十目筛组(P<0.05)。十四目筛组的高档肉块比例和上脑重显著高于其它3个处理组,牛柳重显著低于其它处理组,七目筛组西冷重高于十目筛组(P<0.05)。养殖效益则以十目筛组阉牛最高。     

Effects of growth rate during the early fattening period on growth, carcass characteristics and circulating hormones in the different growth hormone genotypes of Japanese black steers

One of the bovine growth hormone (GH) genetic variants is a substitution of leucine (Leu) to valine (Val) at amino acid position 127 of the protein. The GH genotypes of 14 Japanese black steers used in the present study were Leu/Leu (A, n = 7) and Val/Val (B, n = 7). The steers in each genotype group were divided into two groups based on intended growth rate (high, 1.0 kg/day; low, 0.6 kg/day) during 10–17 months of age. The overall mean concentration of plasma GH was higher (P < 0.05) in the A group than in the B group. The serum concentration of insulin‐like growth factor‐I was higher (P < 0.05) in the B group than in the A group. The carcass weight of the A group was greater (P < 0.01) than that of the B group. However, there was no significant difference in carcass weights between the 1.0 kg/day and 0.6 kg/day groups (P > 0.05). The rib thickness of the 1.0 kg/day group was greater (P < 0.05) than that of the 0.6 kg/day group. The crude fat content of longissimus muscle was greater (P < 0.05) for the 0.6 kg/day group compared with the 1.0 kg/day group.     

Tenderization potential of Hanwoo beef muscles from carcasses with differed genders and loin intramuscular fat content levels during post mortem ageing

Carcasses from Hanwoo steers (n = 15) and cows (n = 15) were classified into three groups: group 1 (G1), the carcasses had 10% to < 11.5% intramuscular fat (IMF) in loin muscles; group 2 (G2), the carcasses had 13% to < 14.5% IMF in loin muscles; and group 3(G3), the carcasses had 17% to < 18.5% IMF in loin muscles. These were used to evaluate the effects of gender and carcass group on quality traits and Warner–Bratzler shear force (WBSF) of Psoas major (PM), Longissimus thoracis (LT), Longissimus lumborum (LL), Longus colli (LC), Supraspinatus (SS), Latissimus dorsi (LAD), Semimembranosus (SM), Quadriceps femoris (QF), Biceps femoris (BF) and Semitendinosus (ST) muscles. Our results showed that pH values of LT, LL, LC, BF and QF muscles were lower in steers than in cows (P < 0.05). Water holding capacity (WHC) was found higher in LC, SS, LAD and QF muscles of steers (P < 0.05). At day 2 of ageing, gender affected the WBSF values of only PM, LD and QF muscles in G1, and QF muscle in G3; however, with additional ageing, the gender effect was observed for most of the muscles. Most muscles showed ageing responses; however, the rates of ageing response significantly varied depending on gender and carcass groups. The muscles of G1 and G2 had generally higher tenderization potentials than those of G3. Furthermore, most muscles in G3 had generally lower WBSF values than in G1 and G2. These results clearly indicate that ageing has a significant effect on quality and WBSF of beef muscles, and the classification by loin IMF level may be useful for prediction of the tenderness of other muscles.     

Feedlot and Carcass Performance of Angus-, Brangus-, Gelbvieh-, and Gelbray-Sired Crossbred Steers

Feedlot and carcass traits were evaluated for steers (n = 231) sired by Angus (A), Brangus (BA), Gelbvieh (G), and Gelbray (GB) bulls (n = 29) out of first cross (F₁) Brahman-Hereford cows. Steers were produced over 4 y and were born during spring and fall calving seasons. Brahman inheritance was 25% in A- and G-sired steers, and 44% in BA- and GB-sired steers. After weaning, steers were stockered before entering the feedlot. Steers produced in 1993 and 1994 were fed in Louisiana and individually harvested at a targeted backfat thickness of 10 mm. Steers born in 1995 and 1996 were fed in Oklahoma and group harvested at an average backfat thickness of 10 mm. Data were analyzed separately by feedlot location because of significant location and sire breed x location effects. Angus-sired steers had smaller (P<0.05) longissimus areas (LMA) and higher (P<0.01) marbling scores(MS) and quality grades than G-sired steers across both locations. Tenderness was more desirable (P<0.05) for A-sired steers compared with G-sired steers when fed in Louisiana. Angus- and G-sired steers had larger (P<0.01) LMA than BA- and GB-sired steers across both locations. Tenderness was similar (P>0.10) between steers with 25% and 44% Brahman inheritance. These data suggest that more desirable carcass quality and tenderness can be achieved with the use of A sires, relative to the other sire breeds, when mated to F₁ Brahman-Hereford dams. Improved carcass cutability resulted with the use of G sires, and in steers with 25% Brahman inheritance.     

Estimation of the carcass composition from a cross-section of the rib-loin from crossbred Japanese Black × Limousin F2 cattle by computer image analysis

The carcass composition of crossbred Japanese Black × Limousin F2 cattle was examined in order to find an accurate carcass composition equation. The test animals included 17 steers and 17 heifers. The 28 image measurements from the area encircling the vertical line to the thoracic vertebra and the line from the thoracic vertebra between the sixth and seventh rib‐bones were measured by computer image analysis. The relationships between the 29 parameters that added the carcass left side weight of the animal and the carcass composition were suggested. The carcass composition included muscle weight, muscle ratio, fat weight and fat ratio. The carcass composition from steers was estimated by an equation composed of these three or four parameters (R² = 90.80%, 79.30%, 90.75% and 73.70%, respectively). The selected parameters were measured without cutting the thoracic vertebra. The carcass composition from heifers was estimated by an equation composed of two to four parameters (R² = 96.15%, 90.98%, 93.60% and 88.22%, respectively). The parameters for the estimation of the muscle and fat weight, and muscle and fat ratio are very similar. Furthermore, the equations using the parameters could estimate the carcass composition from the Japanese Black × Limousin cattle resource population.     

Estimation of Protein Requirements of Feedlot Steers

Feedlot performance, carcass characteristics, and diet composition data were collected from a survey of finishing steer experiments (40 experiments; 347 kg average initial weight; data excluded Holstein steers). Data were analyzed by weighted (observations/mean) analyses of variance to determine effects of protein intake and implanting strategy on feedlot performance and carcass characteristics. Implanting strategies were defined according to prevalent or last implant type used: no implant (None); medium-potency implants (Medium): zeranol 72 mg per dose, steroid-based implants (Synovex-S or Compudose) or trenbolone acetate (TBA) alone; high-potency implants (High): TBA in combination with either steroids or zeranol. Regression procedures were utilized to estimate CP and DIP, or MP requirements. Implant effects were independent (P>0.60) of dietary protein effects and included faster (P<0.05) gains at higher intakes (P<0.05) that resulted in improved (P<0.05) feed efficiencies. Steers responded to higher dietary CP (13.3 vs 11.4%) by increasing intake (P<0.05) which resulted in faster (P<0.05) and more efficient (P=0.09) gains. Compared to nonimplanted steers, implanted steers had heavier (P<0.05) carcasses with larger (P<0.05) ribeyes and lower (P<0.05) marbling scores. Nonimplanted steers fed 13.3% CP diets had heavier (P<0.05) carcasses than nonimplanted steers fed 11.4% CP diets. Maintenance MP requirements of nonimplanted steers were greater than those of implanted steers and similar to established MP requirements. Diets of steers implanted with high-potency implants must be supplemented to contain more than 7.5 g MP/kg BW^0.75/d, especially at heavy (>450 kg) initial BW, to maximize implant response. Implanted steers have a greater ability to respond to increased dietary protein because of reduced protein requirements for maintenance.     

Effects of dietary supplementation of selenium and iodine on growth performance,carcass characteristics and histology of thyroid gland in goats

This study assessed the effects of dietary selenium (Se), iodine (I) and a combination of both on growth performance, thyroid gland activity, carcass characteristics and the concentration of iodine and selenium in Longissimus lumborum (LL) muscle in goats. Twenty‐four bucks were randomly assigned to four dietary treatments: control (CON), basal diet without supplementation, basal diet + 0.6 mg Se/kg dry matter (DM) (SS), 0.6 mg I/kg DM (IP), or combination of 0.6 mg/kg DM Se and 0.6 mg/kg DM I (SSIP) and fed for 100 days. Animals fed diet SSIP exhibited higher (P < 0.05) body weight and better feed conversion ratio (FCR) than those fed other diets. Dressing percentage of goats fed the supplemented diets was higher (P < 0.05) than that of the control. Carcasses from the IP group had higher (P < 0.05) total fat proportion than the SSIP group. The levels of both elements were significantly elevated (P < 0.05) in LL muscle in supplemented goats. Thyroid follicular epithelial cells of IP and SSIP animals were significantly higher than those of CON and SS groups. The study demonstrated that the combined Se and I dietary supplementation improves growth performance, carcass dressing percentage and increases the retention of Se and I in goat meat.     

Influence of rice whole‐crop silage diet on growth performance,carcass and meat characteristics and muscle‐related gene expression in Japanese Black steers

The present study investigated the influence of a diet largely comprising rice whole‐crop silage (rWCS) on growth performance, carcass and meat characteristics, and expression of genes involved in muscle growth of Japanese Black steers. Steers were randomly separated into rWCS‐fed (rWCS ad libitum and restricted feeding of concentrate) and concentrate‐fed groups. Total digestible nutrient intake and daily gain (DG) decreased in rWCS‐fed steers in comparison with concentrate‐fed steers, whereas dressed carcass weight and final body weight did not significantly differ between the groups. Decreases in drip loss in the muscle of rWCS‐fed steers may be caused by α‐tocopherol and β‐carotene in muscle. Feeding large amounts of rWCS to steers may maintain quantitative productivity of beef steers equally to a concentrate‐based diet, and improve the qualitative productivity. Results of gene expression suggest that activation of skeletal muscle growth in rWCS‐fed steers may occur at the late fattening period owing to a decrease in myostatin and increase in myosin heavy chain gene expression. Preadipocyte factor‐1 and myostatin genes may be strongly involved in the control of lipid accumulation. This rearing system would allow beef production to switch to rWCS‐based diets from concentrate‐based diets.