Effects of placing cattle on feed at two-month intervals and housing on feedlot performance and carcass grades

A 5-yr study was conducted involving the placement of yearling steers on feed at 2-mo intervals under three different housing systems. A total of 3,571 steers (180 pens) initially averaging 318 kg was used. Evaluations were made for DM intake, ADG, feed efficiency (FE), carcass quality (QG), and yield grades (YG). Cattle were assigned to either an open lot with overhead shelter (S), an open lot without overhead shelter (NS), or an open-front confinement building (C). Each treatment consisted of two lots of 20 steers each per interval per trial. Corn grain provided 85% of the energy; the remainder was supplied by corn silage and protein supplement. Cattle were fed 140 to 180 d to achieve an average slaughter weight of 500 kg. The main effects of year (Y), month (M), and housing (H) affected DM intake, ADG, FE, and final live weight (P less than .01). The interactions for Y x M, M x H and Y x M x H affected ADG (P less than .05). Month and H affected hot carcass weight (P less than .01). Year affected YG, and year and month affected QG (P less than .01). Month effects on DM intake and ADG indicated that cattle started in May had the highest intake and ADG (P less than .05) and that cattle started in November had the lowest (P less than .05) DMI and ADG. Month effects on FE indicated that cattle were most efficient when placed on feed during March, May, and July (5.82, 5.72, and 5.66 kg DM/kg gain; P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of monensin and tylosin on average daily gain, feed efficiency and liver abscess incidence in feedlot cattle

Fourteen trials were conducted to evaluate the effects of feeding monensin at 33 ppm alone, tylosin at 11 ppm alone and the two feed additives in combination on the average daily gain, average daily feed intake, feed:gain ratio and the incidence of liver abscesses in feedlot cattle. Monensin reduced feed intake and improved feed efficiency (P less than .05), and had no effect on average daily gain. Tylosin improved average daily gain (P less than .05) and had no effect on daily feed intake. The effect of tylosin on feed efficiency approached significance. The interaction of monensin and tylosin was nonsignificant for daily gain, daily feed intake and feed:gain ratio. Monensin had no effect on liver abscess incidence, while tylosin reduced abscess incidence from 27 to 9%.     

Response to virginiamycin in finishing beef bulls fed a maize silage diet or a complete dry feed

Two experiments have been conducted to study the effect of virginiamycin in a maize silage diet (I) or a complete dry feed (II). Virginiamycin was incorporated at 0 or 65 mg per kg concentrate which was fed at 0.75% of the live weight of 43 Belgian white-red bulls (I), or at 0 or 25 mg per kg complete dry feed for 24 Belgian white-blue bulls (II). In the first experiment daily gain was increased by virginiamycin from 1.28 to 1.38 kg without effect on intake, but with an improved feed conversion from 5.99 to 5.60 kg dry matter/kg gain. In the second experiment daily gain, daily dry matter intake and feed conversion were not influenced by virginiamycin. The differences between experiments may suggest that the response to virginiamycin probably depends on the diet type, although no significant interaction was found between diet type and virginiamycin with regard to growth rate (P greater than 0.10). In both experiments, fasting weight loss, dressing percent and carcass classification and composition were not affected by virginiamycin.     

Productivity and profitability of twin births in beef cattle

Data from 1,277 single and 85 twin calvings, occurring in both spring and fall from 1980 through 1987, were used to examine the productivity and profitability associated with twin births in beef cattle. Pregnancies in pure and crossbred cattle resulted from both AI and embryo transfer. Cows and calves were confinement-housed. Cows were individually fed to specification. Calves were given ad libitum access to creep feed and those born in 1986 and 1987 were fed to slaughter. The influence of birth number of gestation length, total calf birth and weaning weights, lactation yield, and cow fed intake during both the dry and lactating periods were examined. Twin-bearing cows had their gestation length shortened by 6.4 d (2%); yielded 25.5 (59) and 186.0 kg (73%) more weight of calf at birth and weaning, respectively; had lactation yield and lactation feed intake increased by 25 and 20%, respectively; and had precalving (dry) period feed intake no different from their single-bearing counterparts (P = .12). Postweaning growth was not different for single and twin calves (P = .50); twin gain, relative to initial size, was higher. Feedlot feed intake of twins was 85% of that for singletons (P = .20). Twins were 90% of singleton live weight at slaughter and yielded 93% of singleton hot carcass weight (P = .12). Twins were slightly older and significantly leaner at slaughter. Returns less feed costs showed twin births to be associated with increased profit for cow-calf programs. Returns less feed and overhead costs were higher for twin calves than for singles in the feedlot.     

Responses to dietary additions of fiber (alfalfa meal) in growing pigs housed in a cold, warm or hot thermal environment

Five trials involving 112 individually-penned animals were conducted to determine the effects of dietary fiber additions (0 or 10% dehydrated alfalfa meal) on the rate and efficiency of growth and carcass characteristics of growing pigs housed in a cold (10 C), thermoneutral (22.5 C) or hot (35 C) thermal environment. Cold exposure (10 C) depressed efficiency of feed and energy utilization, carcass length, backfat, cold carcass dressing percentage and percentage lean cuts. Exposure to the hot environment resulted in depressed live weight gains but did not alter the efficiency of feed utilization. Dietary additions of alfalfa meal depressed daily gains by 1, 3 and 5% in pigs housed in the cold, warm and hot environments, respectively, and gain:feed ratios by 1, 7 and 10%. Ingestion of the fibrous alfalfa meal depressed cold carcass dressing percentage in the 10 and 22 C environments as compared with the basal diet. Based on these data, the nutritional value of fibrous feedstuffs (15% total dietary neutral detergent fiber or less) for growing pigs allowed to consume feed ad libitum is greater in animals housed in a moderately cold vs a warm or hot thermal environment.     

Effect of testosterone propionate on performance and carcass characteristics of heifers and cows

Two experiments were conducted to evaluate the effect of testosterone on growth and composition of cattle. In the first experiment, crossbred yearling heifers (n = 48) were assigned to four treatments: 1) control (no implant), 2) Synovex-H implants on d 1 and 84, 3) one testosterone propionate implant administered on d 1 and a second on d 84 and 4) two testosterone propionate implants administered on d 1. Heifers were fed a high-energy diet for the 157-d study. Implanting with the high-testosterone treatment improved (P less than .05) daily gain and feed efficiency compared with the other treatments. Marbling score was reduced (P less than .05) with the high-testosterone treatment. In Exp. 2, mature cows (n = 36) were assigned to one of three feeding periods (0, 42, or 84 d) with the cows fed 42 or 84 d subdivided into two groups (implanted with testosterone propionate or nonimplanted control). Cows were fed a high-energy diet and slaughtered at the end of each feeding period. Testosterone did not influence (P greater than .05) feedlot performance. Increased time on feed reduced (P less than .01) daily gain (live weight basis) and feed efficiency but did not influence feed intake. Testosterone treatment had little influence on the fat and moisture contents of the carcass soft tissue or on the palatability characteristics of loin steaks. Time on feed increased lean muscle mass and carcass fat (P less than .05). Sensory traits were improved at 42 d on feed (P less than .05), but no further sensory improvement was observed at 84 d.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of water sulfate concentration on performance, water intake, and carcass characteristics of feedlot steers.

Two hundred forty single-source, cross-bred steers (304 kg) were used to evaluate the effects of various water sulfate concentrations on performance, water intake, and carcass characteristics of feedlot steers. Cattle were stratified by weight and assigned within weight blocks to five water treatments. Averaged over time, actual water sulfate concentrations (+/- SEM) were 136.1 (+/- 6.3), 291.2 (+/- 15.3), 582.6 (+/- 16.9), 1,219.2 (+/- 23.7), and 2,360.4 (+/- 68.2) mg/L, respectively. Weather-related data were recorded. Increasing water sulfate concentration resulted in linear decreases in ADG (P < 0.01) and gain:feed ratio (P < 0.01) and a quadratic effect on water intake (P = 0.02) and tended to quadratically increase then decrease DMI (P = 0.13). Sulfate x period interactions were evident for DMI (P = 0.01), ADG (P < 0.01), and feed efficiency (P < 0.01). Time had quadratic effects on DMI, water intake, ADG, and feed efficiency (P < 0.01 for all models). Increasing water sulfate concentration resulted in linear decreases in final weight, hot carcass weight, and dressing percentage, a linear increase in longissimus muscle area, and a quadratic effect on fat thickness over the 12th rib and predicted yield grade (P < 0.05 for all dependent variables). Mean daily temperature explained 25.7% of the observed variation in water intake. Other factors that explained a significant (P < 0.01) amount of variation in water intake were BW, DMI, water sulfate concentration, barometric pressure, wind speed, and humidity. High water sulfate concentrations had a significant and deleterious effect on performance and carcass characteristics of feedlot steers. Increasing the sulfate concentration in water may have resulted in a functional water restriction early in the trial when ambient temperatures were greatest. However, toward the latter stages of the trial, cattle supplied higher-sulfate water had higher ADG and FE. These improvements later in the trial may represent compensatory gain associated with decreased ambient temperature and water requirements. Averaged over time, a water sulfate concentration of greater than 583 mg/L, equivalent to 0.22% of the diet, decreased feedlot performance.     

Heterosis among closed lines of Hereford cattle. III. Postweaning growth and carcass traits in steers

Feedlot and carcass characteristics of 276 steers from five closed lines of Hereford cattle and reciprocal crosses among these lines were studied. The traits studied were initial weight, final weight, 224-d gain, days on test, hot carcass weight, marbling score, longissimus muscle area, fat thickness, yield grade, dressing percentage and shear force. Year of record was a significant source of variation for most traits. Age of dam was a significant source of variation for growth traits but not carcass traits. Line of sire affected initial weight, final weight, 224-d gain, days on test, marbling score and dressing percentage. Significant heterosis was observed only for hot carcass weight. Heterosis estimates were 1.9% for initial weight, 2.2% for final weight, 2.5% for 224-d gain, -2.1% for days on test, .6% for hot carcass weight, -.6% for marbling score, 0 for carcass grade, .6% for longissimus muscle area, 2.3% for backfat thickness, .9% for yield grade, -.9% for dressing percent and -10.9% for shear force. Initial age on test affected only hot carcass weight. Hot carcass weight, dressing percentage, marbling score, longissimus muscle area and fat thickness were affected by slaughter weight. Slaughter age affected dressing percent and marbling score.     

复合益生菌制剂对肉牛生长性能、屠宰性能及经济效益的影响

为研究不同水平的复合益生菌制剂对肉牛生长性能、屠宰性能及经济效益的影响,试验选择体重(200±4)kg肉牛60头随机分成4组,每组15个重复,每个重复1头,1组饲喂基础日粮为对照组,试验2、3、4组分别添加2.5%、5.0%、10%复合益生菌制剂,预试验7 d,试验期为56 d。结果表明:(1)试验3、4组的平均日增重较1组比分别提高19.4%、18.1%(P<0.05),试验3、4组料重比较1组比分别降低9.6%、7.2%(P<0.05),试验2、3、4组的平均采食量均高于1组(P>0.05);(2)试验2、3、4组的胴体重、屠宰率均高于1组(P>0.05),试验3、4组的宰前活重、眼肌面积较1组比分别提高10.3%、9.0%、14.3%、13.9%(P<0.05);(3)试验2、3、4组试验肉牛的每千克增重成本均低于1组,试验3、4组每千克增重的饲料成本分别减少1.0元和0.77元。综上,不同水平复合益生菌制剂的添加可以提高肉牛的生长性能、屠宰性能及经济效益,以5.0%添加为适宜。     

Mixtures of wheat and high-moisture corn in finishing diets: feedlot performance and in situ rate of starch digestion in steers

Wheat and high-moisture corn (HMC) were fed singly and in three combinations using dry-rolled wheat (DRW) (ratios of 75:25, 50:50, and 25:75, respectively, Trial 1), or singly and in two combinations using steam-rolled wheat (SRW) (ratios of 67:33 and 33:67, respectively, Trial 2) to finishing beef cattle fed a high-concentrate diet. In situ rate of starch digestion (Trial 3) was measured on grains used in Trial 1 (excluding the 25 HMC: 75 DRW mixture) and ground dry corn. In Trial 1 (132 d), gain/feed did not differ (P greater than .10); however, final weight, hot carcass weight, and ADG decreased linearly (P less than .05) and DMI exhibited a cubic response (P less than .05) as the percentage of wheat in the diet increased. Carcass characteristics were not different. In Trial 2 (113 d), there were no differences attributable to treatment for ADG, DMI, gain/feed, or carcass characteristics. Positive associative responses for gain efficiency (gain/feed) were greatest for the first increment of wheat addition (25% DRW and 33% SRW in Trials 1 and 2, respectively) and for the early portion of the feeding period (57 and 28 d for Trials 1 and 2, respectively), indicating a more rapid diet adaptation and(or) less propensity for subacute acidosis. In Trial 3, the treatment grains or mixtures did not differ in rate of starch digestion. Although the differences were not statistically significant, starch in the 100% wheat diet was digested twice as fast as the 100 or 75% HMC mixtures.(ABSTRACT TRUNCATED AT 250 WORDS)     

日粮添加产朊假丝酵母对15月龄新疆褐牛杂交育肥增重性能的影响

为探讨日粮添加产朊假丝酵母菌(Candida utilis)对肉牛育肥增重性能的影响,选取15月龄体重(376.53±30.31)kg的新疆褐牛与哈萨克牛杂交F1代公牛30头,随机分为对照组(CT)与产朊假丝酵母菌组(CU),CT组饲喂全混合日粮(TMR),CU组在TMR中按10 g/100 kg体重添加产朊假丝酵母菌粉剂(活菌数≥4×109 CFU/g)。饲养期为120 d,每隔30 d测定TMR剩料粒度、体重变化,并采用粪筛对粪样分布进行粒度分析。结果表明:在TMR投料配方比例与制作粒度保持不变的情况下,随着育肥期的延长,宾州筛第1层(粒径>19 mm)比例下降,说明添加产朊假丝酵母菌可以提高肉牛对长粗饲料的采食;15月龄肉牛体重变化随饲养天数呈一元线性增长模式;CU组平均干物质采食量(DMI)比CT组降低9.9%(P<0.05);CU组平均耗料增重比(F/G)比CT组下降了15.4%(P<0.05),日增重(ADG)有所提高(P>0.05),说明CU组可以提高饲料转化效率;CU组胴体重高于CT组4.2%(P<0.05),但屠宰率无显著差异;利用粪筛对CU组与CT组粪便粒径分析,中上层比例有所降低表明CU组肉牛对TMR中饲料颗粒消化更加充分。综上所述,日粮添加产朊假丝酵母可以提高15月龄肉牛对TMR中长纤维的采食,DMI降低9.9%,F/G降低15.4%,胴体重提高4.2%。     

冬季不同饲喂方式对大别山黄牛养殖效益的影响比较

[目的]为了研究不同肉牛饲喂方式对大别山黄牛的冬季养殖效益的影响。[方法]试验牛分成两组,分别为试验Ⅰ组和试验Ⅱ组,每组10头,公母随机。Ⅰ组饲喂干稻草,Ⅱ组饲喂精粗混合日粮。测定两组试验牛的平均日增重、日采食量和饮水量。试验期末,每组选择3头（2公1母）试验牛进行屠宰测定,计算屠宰率、净肉率、高档肉块比和优质肉块比。...     

Investigations concerning the use of the rumen fermentation regulator monensin in feeding fattening bulls

In two digestion experiments with wethers and seven feeding experiments with 198 fattening bulls with rations rich in (greater than 55% of the dry matter intake from roughage), the influence of the antibiotic monensin on the digestibility of the ration, on rumen-physiologic characteristic values and on fattening and slaughtering results was investigated. The digestibility of the organic matter and the crude nutrients was not significantly influenced by the use of monensin (20 mg/kg dry matter). The administration of 200 mg monensin per fattening bull and day resulted in an increase of the molar concentration of propionate in the rumen fluid by 9.7 mol%, the concentration of acetate and butyrate decreased by 7.3 resp. 2.8 mol %. On an average of the seven experiments the intake of dry matter was diminished by 5.1% through the use of monensin, the live weight increase remained almost unaffected (3.0% additional increase), feed and energy requirement per kg live weight were improved by 7.9%. The fattening results do not always correspond in the various experiments. The results of the dressing of the carcass, the composition of the carcass and the quality of the meat remained unaffected by the administration of monensin.     

Energy source and ionophore supplementation effects on lamb growth, carcass characteristics, visceral organ mass, diet digestibility, and nitrogen metabolism.

In Exp. 1, 72 Targhee lambs (initial BW 22.1+/-.3 kg) were used to determine the effects of energy source (alfalfa pasture vs limit-fed, all-concentrate) and ionophore addition on performance, visceral organ mass, and carcass characteristics. There were no differences (P > . 10) in ADG or gain/ feed due to ionophore supplementation. Lambs that grazed alfalfa had greater (P < .05) liver, omasum, abomasum, small intestine, cecum, and large intestine weights than did lambs fed the concentrate diet. Lambs fed the concentrate diet had greater (P < .01) hot carcass weights, larger (P < .01) loin eye areas, and greater (P < .001) dressing percentages than lambs that grazed alfalfa. In Exp. 2, lambs offered the concentrate diet had greater (P < .001) DM and OM digestibilities than lambs offered alfalfa (89.5 and 91.1 vs 72.4 and 74.2%, respectively). Apparent and true N digestibilities were greater (P < .001) for the concentrate diet than for alfalfa (90.9 and 101.7 vs 77.7 and 91.9%, respectively). Likewise, grams of N retained per day were twice as great (P < .001) with the concentrate diet than with alfalfa (14.9 vs 6.0 g/ d). The greater visceral organ mass and resulting increases in energy and protein requirements in lambs that grazed alfalfa were probably responsible for the lesser hot carcass weight and dressing percentage compared with lambs fed 100% concentrate.     

Effect of concentrate level and live yeast (Saccharomyces cerevisiae) supplementation on Texel lamb performance and carcass characteristics

An alternative additive that improves the nutrient use by ruminants and reduces the use of antibiotics is desirable in order to promote a sustainable and ecological animal production. The objective of the study was to evaluate the supplementation of live yeast (Saccharomyces cerevisiae) in diets of finishing lambs fed with different concentrate levels on their performance, carcass traits, metabolic profile and eating pattern. The trial was carried out at Institute of Animal Science and Pastures, in Nova Odessa city, Brazil, with 24 Texel lambs, 18.0 Kg±1.14 Kg of initial live weight, and averaging 70 days-old, kept in individual pens. The animals were fed with diets comprising hay and concentrate rations in two different proportions (80 or 60%, on DM basis), supplemented or not with live yeast. A completely randomized blocks design, on a 2×2 factorial arrangement (2 concentrate levels with presence or absence of live yeast), was used to compare the means. Supplementation with live yeast did not affect (P>0.05) DM intake, feed conversion, daily live weight gain, total live weight gain and final live weight, although it increased cold carcass weight (P=0.0135) and external carcass length (P=0.0104) regardless of the concentrate feed proportion in the diet. On carcass traits, supplementation with live yeasts did not modify (P>0.05) cold carcass dressing percentage, compactness index, leg length, external chest depth, buttock circumference, carcass fat cover score, and conformation score. Lambs fed diets with greater concentrate level (80%) significantly increased (P<0.05) DM intake, feed conversion, daily live weight gain, total and final live weight gains, cold carcass weight, compactness index, external carcass length, external chest depth, and buttocks circumference and did not modify (P>0.05) the cold dressing percentage, degree of carcass fat cover score and conformation. The live yeast decreased plasmatic lactate (P<0.05), did not affect (P>0.05) plasmatic glucose, and reduced (P<0.05) serum urea, only on the higher concentrate diets. The proportion of concentrate did not affect (P>0.05) the plasmatic glucose and lactate. Supplementation of live yeasts did not improve (P>0.05) the rib eye dimensions and the carcass subcutaneous fat thickness measured by ultrasound. Lambs on diet with greater concentrate level had smaller (P<0.05) ingestion and rumination time. The supplementation with live yeast increased the rumination time and did not modify the ingestion time. It can be concluded that live yeast supplementation increases the weight and the carcass length, regardless of the amount of concentrate added to the diet.     

Evaluation of an inactivated Neospora caninum vaccine in beef feedlot steers

OBJECTIVE: To evaluate effects of vaccination of feedlot steers against bovine neosporosis on weight gain, feed intake and efficiency (feed intake per gain), and carcass characteristics. DESIGN: Longitudinal observational study. ANIMALS: 60 weaned Brangus steers seronegative for Neospora caninum. PROCEDURE: Steers were assigned to age-matched control and treatment groups. Steers in the treatment group received N. caninum vaccine on days 79 and 106, while control steers received 2 placebo injections. For each steer, serologic status for N. caninum was determined on days 0 (weaning), 51, 79, 106, 135, 163, 191, 219, and 247 by use of an ELISA; body weight was determined on the same days and at slaughter (day 259). Daily feed intake per steer was measured from days 79 to 259. RESULTS: Seroconversion occurred in 23 of 30 (76.7%) steers in the vaccinated group. Immediately after vaccination, average daily gain, average daily feed intake, and feed efficiency were significantly greater in the treatment group than in the control group, but these differences did not persist. No differences between groups were found in regard to live weight at slaughter, hot carcass weight, dressing percentage, or quality grade; however, steers in the vaccinated group had significantly lower yield grades than did control steers. CONCLUSIONS AND CLINICAL RELEVANCE: In feedlot steers, use of this vaccine against N. caninum was safe and did not affect overall feedlot performance or meat quality; effects on yield grade require further evaluation.     

贵州不同杂交肉牛生产性能的研究

为了探讨西门塔尔牛、安格斯牛、利木赞牛改良本地黄牛的效果,选取18～20月龄,体重280±15.8 kg的西本杂、安本杂及利本杂F1代公牛各20头,按品种分为3组;以青贮玉米和白酒糟为基础粗料,经过6个月的集中肥育,研究杂交肉牛肥育效果与品种的关系,进而分析各项屠宰指标.结果表明：西本杂的平均日增重和料肉比最高,利本杂的日增重和料肉比最低;西本杂、安本杂的宰前活重、胴体重、屠宰率和高档肉重与利本杂相比,差异极显著（P＜0.01）,净肉率和骨肉比值差异显著（P＜0.05）;3组试验牛的大理石纹等级和背膘厚度差异不显著（P＞0.05）.     

Shade effects on performance,carcass traits,physiology, and behavior of heat-stressed feedlot heifers

To determine whether shade influences performance, carcass traits, immunology, respiration rate, and behavior of cattle under conditions similar to those in commercial feedlots, we used 168 heifers in 12 soil-surfaced pens. Six pens were shaded with a galvanized steel-roofed shade (approximately 4 m high), allowing for 2.12 m2 of shade/heifer, and six pens served as the unshaded control. Heifers were fed a 90% concentrate diet during the 121-d trial that began in mid-June, performance variables (DMI, BW, ADG, gain:feed) were measured, and dietary concentrations of NEm and NEg calculated from performance data. A blood sample was collected to assess immune measures. Respiration rates and behaviors (feeding, drinking, walking, standing, lying, agonistic, and bulling) also were measured during the study. Carcass data (yield grade, kidney, pelvic, and heart fat, longissimus muscle area, hot carcass weight, quality grade, liver abscess rate, and incidence of dark-cutting beef) were collected at slaughter. Shaded heifers had higher (P < 0.05) DMI, ADG, and final BW than unshaded heifers. The gain:feed ratio and calculated dietary NEm and NEg concentrations did not differ (P > 0.26) between treatments. Most carcass traits did not differ between treatments, but more (P < 0.02) carcasses ofheifers in shaded pens graded USDA Choice than those in unshaded pens, which resulted primarily from the incidence of dark cutters being decreased (P < 0.04) by approximately half in carcasses from shaded compared with unshaded heifers. Respiration rate and percentage of circulating neutrophils were decreased (P < 0.01) for shaded compared with unshaded heifers. The treatment x time of day effect was significant (P < 0.05) for all behavioral measurements. Shaded heifers spent more time laying down (0800, 1200, and 1500, P < 0.05) and less time standing (1200 and 1500, P < 0.05) than unshaded heifers. Agonistic behavior was less (P < 0.05) for shaded than for unshaded heifers at 1900 and 2000, and bulling was less (P < 0.05) for-shaded than unshaded heifers at 2100. Results suggest that shade improved performance and altered behavior by feedlot heifers during the summertime in West Texas.     

Effect of prenatal androgenization on growth performance and carcass characteristics of steers and heifers

Two experiments were conducted in which pregnant crossbred cows were randomly assigned to a control group or implanted with testosterone propionate/silastic implants between d 110 and 140 of gestation in Exp. 1 and between d 80 and 110 of gestation in Exp. 2. Androgenized heifers (TH) and treated steers (TS), born to implanted dams, possessed similar birth weights compared with control heifers (CH) and steers (CS), respectively, in both experiments. In Exp. 1, yield grades were lower (P less than .05) for TH than for CH. In Exp. 2, TH possessed 9.4% greater (P less than .07) 205-d adjusted weaning weights and 9.8% heavier (P less than .05) adjusted yearling weights than CH. In Exp. 2, daily gain was 19.5% faster (P less than .05) and feed intake was 13.6% greater (P less than .05) for TH than for CH. In Exp. 2, TH possessed less (P less than .05) s.c. fat, greater (P less than .10) carcass weight gains and lower (P less than .05) yield grades than CH. Liver weight per unit of carcass weight was greater (P less than .07) for TH than for CH in Exp. 2. Androgenized heifers had lower (P less than .07) lipid content in the 9-10-11th rib section than did CH. Calving intervals were similar for implanted and nonimplanted cows in both experiments. Results from these two trials suggest that efficiency of heifers for producing carcass beef can be improved by prenatal testosterone exposure.     

Fattening ability and carcass value of Dhamari and Tehami ram lambs,F1 crossbreds of Dhamari × Tehami in Yemen

A fattening experiment was carried out to analyze and evaluate the effect of ram lamb genotype on the growth, feed conversion (FC), and carcass value of Dhamari ram lambs, F1 crossbreds of Dhamari?×?Tehami (F₁ DhT), and Tehami ram lambs. Genotype of the ram lambs including the experiment (n?=?30) had high significant effect on total weight gain (TWG), average daily gain (ADG), and FC (P?P?P?P?P?P?P?1 DhT was better than Tehami ram lambs in ADG, TWG, and FC. Additionally, the results show that the feed conversion was in F₁ DhT crossbreds ram lambs better than pure Dhamari and Tehami ram lambs, mainly in the carcass indicators.