Dietary forage concentration and particle size affect sorting,feeding behaviour,intake and growth of Chinese holstein male calves

The objective of study was to evaluate the effect of forage concentration (F:C) and forage particle length (FPL) on sorting, feeding behaviour, intake, growth and body measurements of growing calves. Twenty‐eight weaned calves of body weight 156.79 ± 33.44 (mean ± SD) were used in 2 × 2 factorial arrangements with the factors FPL of hay grass (full and short) and hay grass concentrations (low, 50% and high, 65%). The treatments were as follows: full length (FL) with low F:C (50:50), FL with high F:C(65:35), short length (SL) with low F:C (50:50) and SL with high F:C (65:35). Increasing F:C and decreasing FPL enhanced sorting for short and fine particle and sorting against long particle (p < 0.05). Dry matter intake (DMI) was decreased by decreasing the FPL (p < 0.05). Increasing F:C (65:35) increased the DMI (p < 0.05). A positive interaction between FPL and F:C was found for (daily weight gain) DWG, weight gain (WG) and feed conversation ratio (FCR) (p < 0.05). In case of feeding behaviour, interaction for eating time and eating time per kilogram DM was present. Increasing the F:C increased the eating time in both FL and SL (p < 0.05). Chopping of hay had decreased the chewing time (p < 0.05). Increasing F:C increased chewing time per kilogram DMI. High F:C decreased the lying time (p < 0.05) in FL and SL treatments (p < 0.05). Increasing F:C reduced the overall abnormal behaviour (p < 0.05). These results suggested that animals performed better at higher F:C at SL diet. Intensity of sorting for short and fine particle and against long particle increased at higher F:C and SL diets. Eating time and eating time per kilogram DMI increased by increasing F:C level in both FL and SL treatments. Chewing time increased by increasing the FPL, while increasing the F:C enhanced the chewing time per kilogram DMI and reduced animal's abnormal behaviour.     

Substitution of corn silage with shredded beet pulp affects sorting behaviour and chewing activity of dairy cows

This study aims to evaluate the effects of substituting increasing concentrations of shredded beet pulp (SBP) for corn silage (CS) on nutrient intake, sorting index, intakes of particle size and nutrients, meal and rumination patterns, and chewing activity of dairy cows. Four multiparous (126 ± 13 day in milk) and 4 primiparous (121 ± 11 day in milk) Holstein cows were used in a 4 × 4 Latin square design experiment with 4 periods of 21 days. Dietary treatments were (DM basis): 16% of dietary DM as CS without SBP (0SBP); 8% CS and 8% SBP (8SBP); 4% CS and 12% SBP (12SBP); and 0% CS and 16% SBP (16SBP). We observed a reduction in the extent of sorting against long particles and medium particles but for fine particles with increasing SBP levels in the diets. The number of eating bouts per day was lesser (8.2%) in cows fed SBP diets compared with 0SBP cows and corresponded with a reduction in eating time per d across treatments. The number of ruminating bouts per day was similar across diets (16.8 bouts/day), but substituting SBP for CS in the diets tended to decrease linearly ruminating bout length (5 min/bout) and tended to increase ruminating bout interval (8 min/day). Eating, ruminating and total chewing time when expressed as minutes per kilogram of forage NDF intake and peNDF > 8 intake increased when SBP was substituted for CS in the diets. Primiparous cows had greater ruminating time (57 m/day) and total chewing time (73 min/day), eating rate (0.01 kg of DM/min) compared with multiparous cows. Also, increasing forage NDF and peNDF_>8, >8‐mm DM intakes are effective means of stimulating ruminating and chewing activities. This study showed that SBP could partially replace CS and not affect DM intake, but chewing activity may decrease slightly.     

Detailed genetic analysis of feeding behaviour in Romane lambs and links with residual feed intake

Breeding strategies based on feed efficiency are now implemented in most animal species using residual feed intake (RFI) criteria. Although relevant, the correlated responses of feeding behaviour traits resulting from such selection on RFI are poorly documented. We report the estimated feeding behaviour at three time levels (visit, meal and day) and genetic parameters between the feeding behaviour traits and their links with RFI and its components. Feed intake, feeding duration at three time levels (per visit, meal and day), feeding rate, number of visits and time‐between‐visits were estimated for 951 Romane lambs fed via automatic concentrate feeders. Heritability estimates of feeding behaviour traits ranged from 0.19 to 0.54 with higher estimates for the day level than the visit level. Daily feed intake was not genetically linked to feed intake at the visit level, whereas feeding duration between visit and day levels was moderately correlated (R_g = +0.41 ± 0.12). RFI was not significantly correlated with feeding rate, but was positively linked to feed intake and feeding duration at the day level (+0.73 ± 0.09 and +0.41 ± 0.13, respectively) and negatively at the visit level (?0.33 ± 0.14 and ?0.22 ± 0.17, respectively). Selecting animals with lower RFI values might modify their feeding behaviour by increasing feed intake and feeding duration at the visit level but decrease the number of visits per day (+0.51 ± 0.14).     

Fattening performance and feed source preference of native Awassi lambs fed individually in a cafeteria feeding system

This experiment was conducted to investigate the effect of cafeteria (CF) and conventional (CN) feeding systems on feed intake, feed preferences with respect to voluntary feed source intake, feed conversion rate (FCR) and fattening performance of native Awassi lambs. Sixteen, 3 month old male lambs were used and kept individually for 70 days. Lambs in CF (n = 8) were offered to consume the main ingredients of barley, soybean meal (SBM), sunflower seed meal (SFM) and alfalfa straw, separately, while lambs in CN (n = 8) were fed with a concentrate feed containing 11.34 MJ/kg ME, 17.53% crude protein with the mixture of the same feed sources and alfalfa straw. The initial and final live weights of lambs were similar among groups (P > 0.05). Daily voluntary intake of ash, fat and neutral detergent fiber (NDF) consumptions among groups were quite different during the experiment (P < 0.001). Neither biweekly nor total results of voluntary protein intake between groups were not found statistically significant (P > 0.05). From beginning to the end of the study, the proportional barley intake increased 34 to 43% but reduced for SBM intake from 37 to 23% for the lambs in CF. On the other hand, the SFM intake of lambs did not changed significantly during the experiment and ranged between 2–5%. Lambs in CF did not consume SFM to meet their protein requirement and had 12.5% better total FCR result than the lambs in CN (6.86 and 7.84, respectively) (P > 0.05). The difference of average DWG, total live weight gain, final live weight of lambs in groups were similar (P > 0.05). In conclusion, Awassi lambs in CF can select a diet matching their nutritional requirements from a group of feed sources in response to their growth period when compared to CN system and better FCR result might help to decrease the feed expenses for fattening of native Awassi lambs.     

Growth performance and meat characteristics of hair lambs grazing stargrass pasture without supplementation or supplemented with concentrate containing different levels of crude protein

Abstract

Forty crossbreed hair lambs (19.1 kg body weight; 8 months of age) grazing on a Cynodon plestoctachyus pasture without supplementation or supplemented with 300 g of concentrate containing different levels of crude protein (CP) were randomly assigned to treatments defined as follows: control (without supplementation); CP130 (concentrate 130 g CP/kg), CP150 (concentrate 150 g/kg), CP170 (concentrate 170 g/kg), and CP190 (concentrate 190 g CP/kg). Lambs fed supplements had higher final body weight (BW), total gain, average daily gain (ADG), total dry matter intake (DMI), total tract digestion, and carcass dressing than lambs in control treatment. Final BW, total gain, ADG, total DMI, feed conversion, and total tract digestion were improved linearly as protein level in concentrate increased. Meat of lambs fed supplements was lighter, redder, and less yellow than meat of lambs in control treatment. It is concluded that supplementation improved ADG, feed conversion, carcass dressing, and meat color.     

Effects of dietary concentrate level and chromium-methionine supplementation on ruminal fermentation,and ruminal bacterial and fatty acid composition in Tan lambs北大核心CSCD

This study evaluated the effects of dietary concentrate level and chromium methionine(Cr-Met)supplementation on ruminal fermentation and fatty acid composition, and ruminal bacteria abundance in Tan lambs. Forty male Tan lambs [(21.00±1.23) kg body weight, 5 months of age] were randomly assigned to four treatment groups with 10 lambs in each treatment. The treatments were: a low-concentrate (LC) diet (concentrate:forage, 35:65) without Cr-Met supplementation; a high-concentrate (HC) diet (concentrate:forage, 55:45) without Cr-Met supplementation; groups fed the HC diet with 0.75 or 1.50 g·d-1·lamb-1 Cr-Met (HCM and HCH, respectively). Ruminal fluid was collected on day 65 with an oral stomach tube about 3 h after the morning feed and samples used for fermentation analysis, fatty acid composition determination and bacterial DNA extraction. It was found that: 1) Ruminal pH, acetate proportion and acetate:propionate were greater (P<0.05) with the LC diet whereas microbial crude protein, propionate and valerate proportions were greater (P<0.05) with the HC diet. The acetate:propionate was greater (P<0.05) in the HCM group than in the HC group. 2) For the HC diet, the DNA abundances of Butyrivibrio fibrisolvens vaccenic acid subgroup (Butyrivibrio VA) and Ruminococcus flavefaciens were decreased (P<0.05), compared with the LC diet, whereas the DNA abundance of Anaerovibrio lipolytica was increased (P<0.05). For lambs fed the HC diet, DNA abundances of B. fibrisolvens stearic acid subgroup, Butyrivibrio VA, Butyrivibrio proteoclasticus, and A. lipolytica showed a linear decrease (P<0.05) with increasing Cr-Met supplementation level; However, the DNA abundance of R. flavefaciens showed a linear increase (P<0.05). 3) Compared with the LC group, the concentrations of t11 C18:1, trans C18:1, c9t11 CLA, t10c12 CLA, C18:2n6, and C18:3n3 were decreased by the HC diet without Cr-Met supplementation whereas the concentration of C18:0 was increased. There was a linear increase in t11 C18:1 and trans C18:1 with increasing Cr-Met supplementation level in lambs fed the HC diet. The results suggest that the HC diet inhibited the growth of ruminal bacteria involved in the ruminal biohydrogenation process, and the addition of Cr-Met had a potentially positive effect on conjugated linoleic acid (CLA) synthesis in body tissue. © 2022, Editorial Office of Acta Prataculturae Sinica. All rights reserved.     

The effect of concentrate level and concentrate composition on the performance of growing dairy heifers reared and finished for beef production

Abstract

The objectives of the study with growing dairy heifers were to determine the effects on animal performance of (1) concentrate level and (2) the concentrate composition in the grass silage-based diet. Animals (30 heifers) were randomly assigned to three feeding treatments: (1) low level (1.75 kg dry matter (DM)/d) of rolled barley (LB); (2) low level (1.75 kg DM/d) of commercial pelleted concentrate (LC); and (3) medium level (3.5 kg DM/d) of commercial pelleted concentrate (MC). All animals were also offered grass silage and hay. The commercial concentrate contained more crude protein than barley grain (135 g/kg DM vs. 205 g/kg DM). The data were analysed using analysis of variance and differences between the treatments were tested by orthogonal contrasts: LC vs. MC and LB vs. LC. The growth of the heifers increased and carcass conformation improved with increasing concentrate level. Commercial concentrate did not improve animal performance compared with barley grain.     

日粮粗蛋白质水平对育肥湖羊瘤胃微生物组成和发酵参数的影响

为研究日粮粗蛋白质水平(crude protein, CP)对育肥湖羊瘤胃微生物、pH及VFA含量的影响,选取54只4月龄[(32.25±2.50) kg]湖羊公羔,采用完全随机分组设计,将试验羊分为3个处理组,每个处理组18个重复,每个重复1只羊,3个处理组日粮CP水平分别为11.5%、14.0%、16.5%,试验期共70 d,包括7 d预试期,63 d正试期。试验期结束后,每组选择10只试验羊进行屠宰,测定屠宰性能并采集瘤胃内容物,用于瘤胃微生物DNA提取。结果表明:1)不同CP处理组对宰前活重、胴体重、屠宰率、瘤胃总重、瘤胃组织重及尾脂重无显著影响(P> 0.05)。2) 11.5%CP组瘤胃液氨态氮显著低于14.0%CP及16.5%CP组(P <0.001),但14.0%CP组与16.5%CP组无显著差异(P>0.05)。瘤胃液p H随日粮蛋白水平的增加有增加的趋势(P <0.1)。3)总挥发性脂肪酸(total volatile fatty acids, TVFA)浓度不受日粮中CP水平的影响(P> 0.05),其中乙酸、丙酸、异丁酸、丁酸、戊酸...     

补饲水平对甘肃高山细毛羊血液指标及其羔羊体重的影响

本研究根据40kg中国美利奴泌乳母羊泌乳量分别为0.8、1.0和1.2kg时所需营养物质的饲养标准,配制了精粗比分别为5∶5、6∶4和7∶3的3种营养水平日粮Ⅰ、Ⅱ和Ⅲ,对甘肃高山细毛羊泌乳母羊进行冬春季放牧补饲试验,同时以牧户自行补饲少量精料、玉米粒及大量青干草的泌乳羊为对照组。通过测定各组试验羊的血清生化指标和母羊及羔羊的体重变化,探索出适宜的草料供给与营养均衡模式。结果表明,血清葡萄糖(GLU)含量日粮Ⅲ摄入组最高,极显著高于对照组(P0.01),尿素氮(BUN)含量对照组显著高于其余3组(P0.05),胆固醇(CHO)含量日粮Ⅱ摄入组显著(P0.05)或极显著(P0.01)高于其余3组;试验末期总蛋白(TP)、白蛋白(ALB)、谷草转氨酶(AST)和谷丙转氨酶(ALT)含量为日粮Ⅱ摄入组最高,均显著高于对照组(P0.05),而乳酸脱氢酶(LDH)含量日粮Ⅱ和Ⅲ摄入组显著低于其余两组(P0.05);日粮Ⅱ和Ⅲ摄入组母羊日增重显著(P0.05)或极显著(P0.01)高于其余两组。总体来看,日粮Ⅱ和Ⅲ的摄入对母羊血清生化指标及羔羊体重都有显著影响,但为了降低饲养成本,避免能量和蛋白过剩,在放牧的同时补饲日粮Ⅱ为最佳的选择。     

The effect of exogenous purine supply on the endogenous excretion of purine derivatives in the urine of growing lambs

An experiment was made to determine the absorption of purine metabolites in dietary nucleic acids through the digestive tract, and also to determine the utilization of nucleic acids absorbed in the body, using growing lambs. Two pairs of 120‐ and 180‐day‐old twin female lambs with a bodyweight of 18.2–19.0 kg were kept in metabolism crates and fed on purine‐free milk replacement (MR) with supplements of exogenous purine (purine base or purine nucleoside) at a level of 0.2 mmol/BW^0.75/d for 5 consecutive days, and thereafter they were maintained in the crates for 4 days. The daily amount of exogenous purine supply was calculated based on the urinary excreted purine derivatives (PD) in lambs fed on milk replacement alone. A urine sample was collected daily for 9 consecutive days, and the urinary excretion of PD was determined daily. Urinary PD excretion opened to increase within 24 h after the dose of purine bases, and the level was recovered on 3 days after ceasing the exogenous purine supply. The recovery of PD in the urine was about 70% of the purine supplement. When purine nucleosides were added to the feed, urinary PD excretion was initiated within 24 h after dosing, and the values were recovered after ending the purine nucleoside supply. The recovery rate of PD in the urine was only 30% of the supplemented purine. The plasma allantoin levels were almost similar after feeding purine bases and purine nucleosides, and the values were mostly in the range (40–60 µmol/L). These findings indicate that an exogenous purine can be directly incorporated into the body, and the purine as nucleoside is more effectively utilized for the synthesis of nucleic acids than as a purine base in the body of growing lambs.     

The metabolic profile of growing lambs fed diets rich in unsaturated fatty acids

The effect of two diets enriched with unsaturated fatty acids – one containing the addition of dried distillers grains with solubles (DGS) and the other the addition of false flax – Camelina sativa cake (CS) – on some metabolic parameters and hormone concentration in growing lambs was determined in this experiment. A total of 21 ram lambs of the Polish Whiteheaded mutton sheep were divided into three groups (the control, receiving DGS and CS). The diets were administered to animals for 6 weeks. During the experiment, peripheral blood was collected. Glucose (GL), total cholesterol (CH), triglycerides (TG), free fatty acids (FFA), insulin (IN), leptin (LE), triiodothyronine (T3) and thyroxine (T4) were assayed in serum. The age‐dependent reduction in CH and TG limited by both experimental diets were observed. A significant increase in FFA concentration was observed in samples collected in the last, that is, third, time period. This was most probably caused by a 12‐h pre‐slaughter fasting period. A significantly lower dynamic of FFA increase in that experimental period was found in animals receiving the experimental feed. Insulin concentration in DGS‐receiving lambs was increased, in contrast to the CS‐receiving lambs, in which it was lower when compared to the control. LE concentration was decreased by both experimental diets, more markedly in the DGS‐receiving animals. No differences between the experimental groups and the control were observed in T3 and T4 concentrations. The effect of 12‐h pre‐slaughter fasting was statistically highly significant for the levels of examined blood markers and hormones, except for TG and IN in the group of lambs receiving the experimental diet with CS.     

饲粮精料水平和蛋氨酸铬添加剂量对舍饲滩羊生长性能、屠宰性能、肉品质和脂肪沉积的影响

本试验旨在探究饲粮精料水平和蛋氨酸铬(Cr-Met)添加剂量对舍饲滩羊生长性能、屠宰性能、肉品质和脂肪沉积的影响.采用2×3双因素试验设计,2个因素分别为饲粮精料水平和Cr-Met添加剂量,其中饲粮精料水平分别设为35％(低精料饲粮,饲粮精粗比为35:65)和55％(高精料饲粮,饲粮精粗比为55:45),Cr-Met添...     

Competitive behaviour of dairy cows at a concentrate self-feeder

Abstract

We investigated whether feeding cows are disturbed by butting of other cows during the time they are in a concentrate self-feeder, and whether this leads to concentrate leftovers. Forty dairy cows were observed while visiting two self-feeders. If a cow was butted visiting the self-feeder, it was considered as ‘disturbed visit’. When retreating from the feeder within five seconds after being butted, the visit was also considered ‘interrupted’. Half of the visits were disturbed, and 42% of visits were also interrupted. Visits were disturbed particularly when cows’ own feed was dispensed, and in 63% of disturbed visits concentrates were left over. The non-lactating cows, denied concentrates, won leftover concentrates after butting the previous visitor more often than lactating cows. Cows’ weight correlated negatively with visiting and receiving butting. Initiated butting correlated positively with winning leftover concentrates. There is a need for further development of automatic feeders to secure individual concentrate feeding.     

Natural or replacer sources of milk in lambs during feeding adaptation: influences on performance,metabolism of protein and lipid and oxidative/antioxidant status

This study aimed to evaluate the effect of milk feeding using milk replacer (MR) or natural ewe's milk (NEM) for Lacaune lambs on performance, protein and lipid metabolism and oxidative/antioxidant status. These parameters were evaluated during the period of feeding adaptation, which corresponded to 12 days after ewe's separation. Fifteen lambs were selected and divided into two groups: Group A (n = 7) with lambs receiving natural milk; Group B (n = 8) with lambs receiving a milk replacer. Liquid food supply, for both groups, was set according to their body weight, given in two daily periods. Feed intake was also obtained by individual body weight and adjusted according leftovers. Blood samples were collected on three different days (0, 6 and 12) to perform the serum analysis of total protein, albumin, cholesterol, triglycerides, alanine aminotransferase (ALT) and urea. Additionally, the oxidative profile was analysed in sera samples through the assessment of TBARS (reactive substances thiobarbituric acid) and ROS (reactive oxygen species) which aims to identify lipid peroxidation and free radical levels, respectively, as well as the antioxidant profile evaluating glutathione S‐transferase (GST). There was no statistical difference (p > 0.05) between groups on levels of total protein, albumin and globulin. However, cholesterol (day 6), triglycerides (days 6 and 12), urea (day 6) and ALT (day 12) levels differed (p < 0.05) between groups. Values of total protein, globulin, ALT and TBARS differed (p < 0.05) along the time. The average weight gain and body weight differed (p < 0.05) only on day 12, showing that weight gain was higher for lambs fed with NEM. The performance of lambs fed with MR was impaired. Biochemical parameters had a slight variation between groups and along the time, as well as oxidative/antioxidant status did not change in the different liquid diets.     

不同营养水平全饲粮颗粒料对育肥羔羊钙、磷表观消化与代谢的影响

采用单因子分组设计,按同质原则将27只陶塞特(♂)与藏羊(♀)杂交一代公羔(3.5～4月龄)分为三组(每组9只),喂以不同能量与蛋白质水平(NRC、0.8NRC、0.9NRC)的全饲粮颗粒料。在饲养试验期间,从每组选5只试羊进行消化代谢试验,以研究不同营养水平对羔羊钙、磷消化与代谢的影响。试验结果表明:不同能量与蛋白质水平全饲粮颗粒饲料对羔羊钙、磷的表观吸收率和表观存留率均无显著影响(P>0.05)。     

Behaviour and welfare of fattening lambs supplemented with varying sizes and types of straw

The aim was to evaluate the effect of size (long or chopped wheat straw), type (barley or wheat) and presence/absence (1 week) of straw supplementation on behaviour and welfare of fattening lambs. Sixteen lambs (65 days) were individually housed to be used in two simultaneous experiments (8 lambs each) for 5 weeks of fattening. After a habituation period, they were offered straw that differed either in size (Experiment 1) or type (Experiment 2), which was followed by a week without straw and then reallocation of straw. Maintenance behaviours, play and stereotypies were analysed using video recording. Physiological stress responses were measured using blood samples taken at the end of the week without straw and after the reallocation of the straw. A preference test was performed during the last week. Concentrate and roughage consumption, average daily gain and conversion index were estimated. Lambs provided with long straw spent more time eating forage, playing and performed fewer stereotypies (Experiment 1). Lambs given wheat straw increased their play behaviour compared with those given barley straw, without affecting stereotypies (Experiment 2). When the straw was removed, lambs performed more behaviours associated with stress; however, this was not reflected in blood stress indicators. Lambs clearly preferred long straw over chopped straw, but no clear preference was observed between wheat and barley straw. The amount of forage intake was consistent with the time spent eating forage, but the amount of concentrate intake did not vary with eating concentrate behaviour, since the amount of concentrate intake was higher when the straw was removed, especially in Experiment 2. Our results show that size more than type of straw supplement impact the behaviour of lambs. Long straw reduces the stereotypies and increases play. This may improve the welfare and performance of fattening lambs, adding ethical value to a highly appreciated product.     

Dietary protein level affects nutrient digestibility and ileal microbiota structure in growing pigs

This study aimed to determine whether dietary protein content influences pig health as indicated by ileal microbiota structure and coefficients of total tract apparent digestibility (CTTAD) of nutrients. Seventy‐two gilts, with an initial body weight of 29.9 ± 1.5 kg, were used in this 42‐day feeding study. Pigs were randomly allotted to one of three dietary treatments of corn‐soybean meal contained 14, 16 or 18% crude protein (CP). As dietary CP content decreased, the CTTAD of most essential amino acids (AAs), except for arginine and histidine, increased linearly, while those of most nonessential AAs decreased linearly. The concentration of total short‐chain fatty acids (SCFA) was higher in pigs fed the diet with 14% CP content than others. Ileal microbiota structure was changed by dietary treatments. In particular, at the phylum level, the relative abundance of Tenericutes in ileal digesta decreased as the dietary protein content reduced, while that of cyanobacteria increased. At the genus level, the relative abundance of Weeksella, Phaseolus acutifolius, Slackia, Sulfurimonas and Aerococcus showed significant differences among the three dietary treatments. In conclusion, ileal microbiota structure was changed by dietary protein content. Moderate reduction of protein intake can benefit gut health by enhancing the gut microbial fermentation and SCFA formation.     

Effect of sex and feeding system on feed intake, growth, and meat and carcass characteristics of fattening Assaf lambs

The effect of feeding system and sex on intake, growth and carcass and meat characteristics of Assaf fattening lambs was studied. Twenty four weaned Assaf lambs, half males and half females were used. After an adaptation period, lambs were randomly assigned to one of the two feeding systems studied. Control lambs received ad libitum commercial concentrate (70% barley, 22% soybean meal, 4.8% wheat, 0.5% bicarbonate, 2.7% mineral–vitamin premix) and barley straw. Free Choice lambs had ad libitum and separate access to whole barley grain and a protein supplement (73.3% soyabean meal, 16% wheat, 1.7% bicarbonate, 9% mineral–vitamin premix). Lambs were slaughtered at 25 kg LBW. Feed intake was not significantly affected by sex (P > 0.05) but Free Choice lambs showed higher dry mater intake than the Control lambs. Nevertheless, only males from the Free Choice group showed an improvement in feed efficiency rate (P < 0.05) and average daily gain (P < 0.01) relating to the Control lambs. Neither feeding system nor feeding system × sex interaction significantly affected non-carcass weight, fat depots, cold carcass weight, dressing percentage, main proportions of commercial cuts and meat characteristics (P < 0.05). As it was expected, female lambs showed a lower average daily gain and a higher feed conversion efficiency than male lambs (P < 0.001) which was related to a greater fat deposition. Meat characteristics were unaffected by sex, with the exception of longissimus lumborum fat content, which was higher in female lambs.The present results suggest that Free Choice feeding system might be suitable for intensively reared male lambs since improvements in daily weight gain and feed conversion rate were achieved, with no adverse effect on carcass and meat quality. Despite the selected diet of both, males and females, did not differ in the crude protein content, the use of Free Choice feeding system for female lambs did not improve performance compared to the Control group.