Economics of callipyge lamb production

This paper examines the economic implications of callipyge (CLPG) lamb production. The price, as it relates to competing meats and excess fat, significantly impact lamb demand, and CLPG genetics improves those factors. The CLPG phenotype does not affect number or weight of lambs weaned or postweaning ADG, but it does improve postweaning feed efficiency by approximately 10%; dressing percentage approximately 7.5%; and yields of wholesale leg (11.8%), loin (4.7%), rack (2.5%), and shoulder (2.3%). Total production costs for a 59-kg lamb are 4% lower in CLPG lambs due to improved feed efficiency. Assuming pelt and offal value pays for slaughter costs, the costs of normal (N) and CLPG carcasses are the same as for live lambs, $81 and $78, respectively; but, due to dressing percentage, the N carcass weighs 29.2 kg and the CLPG carcass, 31.4 kg. Thus, carcass costs for N and CLPG lambs are $2.77/kg and $2.49/kg, respectively. Decreased feed costs, combined with increased carcass and primal cut yields for CLPG lambs, lowers the price required to recover meat costs for leg, loin, rack, and shoulder by 19.7, 14.4, 12.6, and 11.9%, respectively. Successful marketing of CLPG loin and rack depends on the use of one of several postharvest tenderization procedures. Moisture-enhanced pork is accepted by consumers and often sells for a premium; and moisture enhancement may be appropriate for CLPG lamb. The meat cost per kilogram (including a $.10 per kilogram treatment cost) of tenderized and moisture-enhanced CLPG leg, loin, rack, and shoulder containing 10% added water and ingredients would be lowered to $2.51, $4.65, $5.34, and $1.85, respectively. That represents a total of a 20.9% reduction in cost-basis price. When expressed on the basis of increased revenue from the additional yield of cuts at a given market price, the value of CLPG and moisture-enhanced CLPG cuts from a 59-kg lamb would be, respectively, 14.2% and 23.4% higher than for N lamb. Industrywide adoption of CLPG could increase intermediate-run U.S. profits by $109 million, but the actual effects of CLPG attributes, such as a visual appeal, lower fat and cholesterol content, and reduced seam fat, on consumer demand need to be quantified. If accepted by packers and consumers, moisture-enhanced CLPG lamb has the potential to decrease the cost of lamb to consumers and increase lamb industry profitability.     

新疆也木勒白羊羔羊生长发育规律及其与体尺的相关性研究

试验对0~120日龄新疆也木勒白羊羔羊体尺指标、体重生长发育规律进行了分析,旨在为也木勒白羊品种选育提供理论依据。选择222只也木勒白羊初生羔羊,每30 d对其体尺、体重进行测量,直至120日龄。结果显示,也木勒白羊公、母羔早期各月龄体重、体尺累积增长差异极显著（P<0.01）,公羔生长发育较母羔快,公、母羔30~60日龄生长速度最快,30~60日龄公羔平均日增重（ADG）较母羔多6.8 g/d;体尺指标分析结果显示,体长、体高、管围、脂臀宽和脂臀厚在0~30日龄增长最快,胸围和脂臀长在30~60日龄增长最快,公、母羔脂臀长指标在90~120日龄差异明显;120日龄断奶羔羊体尺与体重表型相关性分析结果显示,羔羊胸围与体重的相关系数最大,脂臀长与体重的相关系数最小。通径分析结果显示,羔羊胸围对体重的直接作用较大,体高、体长、脂臀长和脂臀宽主要通过间接作用影响体重。公羔管围对体重的直接作用大于间接作用,母羔管围对体重的间接作用大于直接作用。     

Feeding forage mixtures of alfalfa hay and maize stover optimizes growth performance and carcass characteristics of lambs

A feeding experiment was carried out to determine the effects of different proportions of alfalfa hay and maize stover on the growth performance and carcass characteristics of fattening lambs. Forty‐two healthy 3.5‐month‐old male Small‐tail Han lambs of 23.89 ± 0.38 kg body mass were assigned to seven groups, which were fed mixed diets composed of maize stover and alfalfa hay containing 0%, 30%, 40%, 50%, 60%, 70% or 100% maize stover on a dry matter (DM) basis. Each lamb received 1.5 kg DM of forage mixture three times daily and supplementary concentrate (0.5 kg corn per lamb per day) for 60 days. Compared with the control forage diet of maize stover only, forage intake rate and forage conversion rate on the 40% maize stover/60% alfalfa hay mixture were 30% and 5% higher, respectively. Body weight, dressing percentage and net income were 6.7 kg, 8% and 94.37 Yuan higher per lamb, respectively. Thus, feeding lambs with a forage mixture of maize stover and alfalfa hay in a ratio of 40:60 optimized the production performance, slaughter performance, and the income derived from lambs.     

Biologically based coefficients for partitioning lamb and wool production costs.

Global competition for selling lamb and wool requires sheep producers to effectively prioritize wool and lamb production. Both products are produced simultaneously, and this makes it difficult to differentially assess costs and net returns. This study addressed this issue by developing coefficients for use in financial analysis of lamb and wool profitability across and within five regions of the United States (Eastern, Midwestern, Intermountain West, Great Basin, and Texas). A procedure was developed using a sheep simulation model to partition the amount of nutrients used for lamb and wool production and then using the partitioning information to determine the proportion of costs to be assessed to lamb and wool production. Blackface breed types, when managed without nutritional limitations, had lamb and wool coefficients of .90 and .10, respectively. Wool breeds with unlimited and limited nutrition had lamb coefficients between .80 and .20 and .60 and .40, respectively. In-depth analysis of the Great Basin system indicated that wool and its improvement may contribute as much, if not more, under certain pricing conditions, as increased prolificacy to enterprise profitability. With low lamb prices ($1.32/kg) and moderate wool prices, the partial net returns for a Merino x Rambouillet were higher than the tested prolific breed type ($13.85 vs $11.27/ewe, respectively). This ranking was reversed under high ($2.31/kg) lamb prices ($47.90 vs $55.22, respectively). The derived method provides a basis for analyzing, comparing, and making management and breeding objective decisions.     

Effects of inbreeding on reproduction and wool production of Rambouillet, Targhee, and Columbia ewes.

Because of a traditional interest in inbreeding as a tool for breed improvement, it was desirable to evaluate the effects of inbreeding on the most important products of the sheep industry, lamb and wool production. The data for this study were based on 13,807 ewe and 16,470 lamb records from Rambouillet (R), Targhee (T), and Columbia (C) sheep collected over 9 or 10 yr from 54 inbred lines. Average inbreeding of the lambs and ewes involved was near 25 and 20%, respectively. The combined effects of lamb's and dam's inbreeding reduced litter weight weaned at 120 d approximately .5 kg for each percentage of increase in inbreeding in every breed. For ewes and lambs of average inbreeding, the reductions relative to noninbred ewes amounted to 12.4, 10.3, and 11.3 kg for R, T, and C, respectively. The reductions constituted declines in weight weaned per ewe of 34, 25, and 28%. Similarly, net reproduction rate (lambs weaned per ewes put into breeding) was reduced more than one percentage point for each percentage of increase in inbreeding, with net declines at average inbreeding of 31.7, 23.5, and 25.7 percentage points for each breed, respectively. These reductions were equivalent to reductions in net rate of 29, 20, and 23%. The combined effect of lamb and dam inbreeding reduced weaning weight by 3.5, 2.6, and 2.2 kg, which constituted reductions of 10, 7, and 6%, respectively. Reduced weaning weight was approximately 30% as important as reduced net reproduction rate in contributing to the decline in litter weight weaned. Effects on fleece weight were curvilinear and amounted to reductions of .35, .18, and .00 kg, respectively, at levels of average inbreeding; however, Columbia fleece weights declined rapidly at levels exceeding 20% for ewes. Potential selection differentials were reduced 16% at inbreeding levels of 25 and 20% for lambs and dams, respectively, and 62% at levels of 55 and 50%. The average economic loss per ewe in value of production was estimated at $17 for average inbreeding and as high as $36 for inbreeding approaching 50%. It seems that the use of inbreeding as a tool for improving productive merit in sheep is much more certain to be a detriment, economically and genetically, than an advantage.     

湖羊多羔肥育性能及其羊肉品质的研究

本试验表明,湖羊具有一母哺双、三羔的潜力,以60日龄断奶窝重测量,哺三羔(40.88公斤)、哺双羔(29.50公斤)分别是哺单羔(15.62公斤)的2.62倍和1.89倍。断奶后继续肥育120天,增重速度、屠宰率、净肉率和眼肌面积都是公羔优于母羔。全期试验表明湖羊多羔肥育可获得较高的经济效益。肉质分析指出,湖羊肥羔肉含高蛋白、低脂肪,氨基酸齐全,总含量高,婴儿必需氨基酸、成人必需氨基酸及赖氨酸占总含量的百分率分别高达50.89％、37.35％和11.85％。     

Characterization of Awassi lamb fattening systems: a Syrian case study

Intensive lamb fattening systems are evolving in developing Middle Eastern countries due to high demand for lambs at favorable prices; however, little is known about their characteristics and constraints. A survey was conducted in Syria involving 241 farmers to characterize the fattening production systems and main constraints, with emphasis on feeding, management, labor, and marketing. Most farmers (90%) considered the income from fattening to be from medium to high, and 57% expressed that lamb fattening along with alternative income sources compose the family's livelihood strategies. Fattening systems offer employment to family members. Market price was the main decision factor to buy and sell lambs, but this was only part of various marketing aspects. Male lambs usually bought at markets at the mean age of 4 months (mean weight of 31 kg) are sold after fattening at a 50–60 kg weight range. The average yearly fattening cycle was 2.7 batches, and the average number of lambs per batch was 232. For 65% (n = 241) of the farmers the major constraint to fattening was feeding cost, and for about a half of farmers (51%, n = 241), disease outbreaks and prices for veterinarian services constituted the second important constraint. Research on least-cost fattening diets and curbing disease problems to increase farmer's income margins is needed. It is expected that due to existing commonalities, the information emerging from this study regarding major constraints to Awassi lamb fattening systems could be useful for an across-synthesis on Awassi fattening production in the region.     

Genetic effects on ewe productivity of crossing D'man and Sardi breeds of sheep

Data from 364 ewes of Sardi (S), D'man (D), S x DS, DS x S, S x D, D x S (F1), F2, D x DS and DS x D breed groups mated to F1 rams were analyzed for fertility, number of lambs born alive, litter size at weaning, litter weight at weaning per ewe joined and mean lamb weight at 60 d. Each ewe was exposed in two seasons and had one or two lambings. Effects of breed group were significant for all traits. The highest number of lambs born alive and litter size at weaning were recorded in D'man (1.84 and 1.45, respectively) and D x DS (1.81 and 1.43, respectively). F1 ewes (S x D and D x S) had the highest fertility (.94) and litter weight at weaning per ewe exposed (13.8 kg). Mean lamb weight at 60 d was highest for S x DS and Sardi ewes (13.4 kg and 13.2 kg). D'man additive effects were positive and significant for number of lambs born alive, litter size at weaning and litter weight at weaning per ewe joined; were significant but negative for mean lamb weight at 60 d; and were not significant, although positive, for fertility. Significant individual heterosis was found for fertility, litter weight weaned and mean lamb weight at 60 d. Maternal heterosis and direct epistatic recombination effects were small for all traits.     

Characteristics of lambs fed concentrates or grazed on ryegrass to traditional or heavy slaughter weights. II. Wholesale cuts and tissue accretion

Targhee x Hampshire lambs (average BW 24 +/- 1 kg) were used to determine the effect of finishing on concentrate or by grazing ryegrass forage on slaughter weights of 52 kg (N) or 77 kg (H) on tissue accretion and lamb wholesale cutout. When fed to similar slaughter weights, the wholesale cuts of concentrate-fed lambs were heavier (P < 0.05) than the same cuts from forage-fed lambs; however, when expressed as a percentage of side weight, carcasses of forage-fed lambs had a higher (P < 0.001) percentage of leg than concentrate-fed lambs. Increasing slaughter weight from 52 to 77 kg resulted in a 1-kg increase in loin weight for lambs finished on concentrate and a 0.60-kg increase for lambs finished on forage (diet x slaughter weight, P < 0.03); however, the increased loin weight for lambs finished on concentrate was due largely to increased fat deposition. For lambs slaughtered at 77 kg, those finished on forage had more lean mass in the leg, loin, rack, and shoulder than those finished on concentrate, but lean mass in these cuts did not differ between diets for lambs slaughtered at 52 kg (diet x slaughter weight, P < 0.01). At the normal slaughter weight (52 kg), concentrate-fed lambs had 50% more dissectible fat than forage-fed lambs, whereas at the heavy slaughter weight, a 79% greater amount of dissectible fat was observed for concentrate- vs. forage-fed lambs (diet x slaughter weight, P < 0.001). Lean and fat accretion rates were higher (P < 0.001) for concentrate-fed lambs than for forage-fed lambs. The lean-to-fat ratio of forage-fed lambs was higher (P < 0.001) than that of concentrate-fed lambs; however, forage finishing decreased accretion rates of all tissues compared with concentrate feeding, and these differences between forage and concentrate feeding were magnified at heavier slaughter weights.     

Feed efficiency, carcass characteristics, and sensory quality of lambs, with or without prolific ancestry, fed diets with different protein supplements.

Data were collected on 130 intact male lambs fed diets based on roughages supplemented with fish meal, soybean meal, or corn gluten-blood meal and slaughtered at 43 kg live weight. A nonsupplemented group served as a control. The lambs represented Romanov (R), Finnsheep (F), a new breed developed in Canada (DLS), Coopworth (C), and Suffolk (S), three first crosses of DLS with R, F, and Booroola Merino (B), and their backcrosses to DLS. Supplemented lambs consumed 16 to 22% less (P less than .05) silage than control lambs. Average daily gains of lambs fed fish meal (226 g) and corn gluten-blood meal (217 g) were higher and feed conversion ratio (4.99 and 5.11) lower than that of lambs fed soybean meal (189 g and 5.48) or control (186 g and 5.76) diets (P less than .05). The cost of feed per kilogram of gain or per kilogram of lean produced was similar in the four treatments but was between C $.23 and .65 cheaper in the protein-supplemented groups when the number of days to reach slaughter weight was considered. The effect of diet on carcass traits and meat quality were minimal. Meat of lambs fed the three protein supplements was less juicy than that of control lambs. With a few exceptions, most of the significant differences among genetic groups in growth, carcass, and sensory traits were mainly between prolific (R and F) and meat-type breeds (C, S, and DLS). Gain in weight was highest in S lambs (199 g/d), but F and R first crosses were the youngest at slaughter (196 and 198 d). The F lambs had higher dressing and kidney fat percentages than meat-type breeds. The DLS lambs had the largest longissimus muscle area (14.0 cm2), whereas C had the smallest (10.7 cm2). The B crosses had larger longissimus muscle area than R and F crosses. The R lambs had more lean and less fat in the 12th rib, whereas C lambs had the lowest lean and a high bone percentage. The toughest and the most tender roasts were those of R and B crossbred lambs, respectively. Roasts from F lambs had the most intense lamb flavor.     

放牧藏羊冷季营养调控试验报告

藏系绵羊在产羔后分为4组,进行为期90天的补饲试验,结果:试验1组只均日补饲优质青干草0.5 kg,母羊和羔羊的增重分别为1.57kg和5.29kg;试验2组只均日补饲精料0.25kg,母羊和羔羊的增重分别为2.36 kg和7.9kg;试验3组只均日补饲精料0.5kg,母羊和羔羊的增重分别为4.25 kg和10.02kg;试验4组只均日补饲营养添砖0.15kg,母羊和羔羊的增重分别为1.7kg和6.51kg。4个试验组均达到了母羊保膘和羔羊成活的目的。其中,第3组母羊和羔羊的增重最高,饲料成本也最高;第1组母羊和羔羊的增重最少,但补饲成本最低。     

营养限饲与补偿对蒙古羔羊体重、血清生化指标及胸脂脂肪因子基因表达的影响

试验旨在研究早期营养限饲与后期快速补偿对蒙古羔羊体重、血清生化指标及胸脂脂肪因子基因表达的影响。选用30只4月龄健康蒙古公羔羊,随机分为对照组(20.26 kg±3.63 kg)与限制组(21.29 kg±3.00 kg)。对照组羔羊自由采食,限制组羔羊维持水平饲养,限制期60 d,限制饲养结束后立刻进入60 d补偿期,补偿期两组饲喂相同日粮。于试验第30、60、90和120天从各组试验羊颈静脉采血,用试剂盒检测血清中甘油三酯(TG)、非酯化脂肪酸(NEFA)、总胆固醇(TC)浓度;并在限制和补偿末期屠宰羔羊,采集胸部脂肪组织,实时荧光定量PCR检测脂联素(Adiponectin)、内脂素(Visfatin)、过氧化物酶增殖物激活受体γ (PPAR-γ)、乙酰辅酶A羧化酶(ACC)基因表达量。结果表明:①限制期,限制组羔羊体重保持维持水平而对照组羔羊体重呈升高趋势;补偿期,限制组羔羊平均日增重显著高于对照组(P< 0.05)。②限制期,限制组羔羊血清中TG浓度在第30和60天时显著低于对照组(P< 0.05),而NEFA在第30天时显著高于对照组(P< 0.05);补偿期,限制组TC浓度在第90天时显著低于对照组(P< 0.05),而TG与NEFA两组间均无显著差异(P >0.05)。③限制期,限制组羔羊胸脂PPAR-γ和ACC基因表达量显著低于对照组(P< 0.05),补偿期两组间无显著差异(P >0.05)。限制期和补偿期两组羔羊胸脂Adiponectin和Visfatin基因表达均无显著变化(P >0.05)。由此可知,营养限制时胸脂脂肪合成与脂肪细胞分化能力减弱,脂肪组织水解动员参与机体能量代谢,补偿时总胆固醇参与机体恢复生长。补偿期限制组羔羊快速增重,但ACC与PPAR-γ基因显著低于对照组。早期的生长限制与后期的补偿生长对羔羊胸脂Adiponectin与Visfatin无显著影响。     

Effect of Nutrient Restriction and Compensation on Weight,Serum Indexes and Gene Expression of Chest Fat Adipokines in Mongolian Lamb

To study the effect of nutrient restriction and compensation on weight,serum indexes and gene expression of chest fat adipokine in Mongolian lamb,thirty male lambs were randomly divided into control group (20.26 kg± 3.63 kg) and feed restricted group (21.29 kg±3.00 kg).The experiment lasted for 120 days,including 60 days for feed restriction and 60 days for compensatory feed.At the end of each stage,five lambs from each group were slaughtered and chest fat was collected.Serum concentration of triglycerides,non-esterified fatty acids (NEFA),total cholesterol were measured.Quantitative Real-time PCR were used to determine Adiponectin,Visfatin,PPAR-γ and ACC genes expression.The results showed that:①The lamb body weight of restricted group kept maintain level and that of control group showed a increase tendency.During the compensatory period,the average daily gain (ADG) of restricted group was significantly higher than control group (P< 0.05).②During the restriction period,serum triglycerides concentration of lambs in restricted group was significantly decreased at day 30 and 60 (P< 0.05),and NEFA concentration was significantly increased at day 30 (P< 0.05).After 60 days of nutritional compensation,all serum parameters we tested were not significantly different between restrict group and control group (P >0.05).③During the restriction period,PPAR-γ and ACC gene expression in restricted group were significantly lower than that of control group (P< 0.05),while no significant differences were found during the compensation period (P>0.05).Adiponectin and Visfatin genes expression in chest fat was not significantly changed throughout the experiment (P >0.05).We could know that nutritional restriction reduced fatty acid synthesis and adipocyte differentiation ability,adipose tissue was mobilized energy metabolism,and total cholesterol was recoveried growth on the compensation.However,the ACC and PPAR-γ genes in restricted group were significantly decreased with the body weight increased rapidly during the compensatory stage.Adiponectin and Visfatin were not significantly different between restricted and compensatory stages.     

Characteristics of Lacha and Rasa Aragonesa lambs slaughtered at three live weights

A study was made of differences in the quality of meat from Lacha (L) and Rasa Aragonesa (RA) lambs slaughtered at 12, 24, or 36 kg live weight. Lambs from both breeds were weaned at 25 to 57 d, approximately 11.5 to 18.5 kg live weight, and fed concentrate and barley straw until slaughter at 24 and 36 kg live weight. Hot carcass weight, cold carcass weight, conformation, color, firmness, and thickness of backfat and color of rectus abdominis muscle were recorded on the carcass. Final pH (pHu), instrumental color (L*, a*, b*), myoglobin concentration, chemical composition, and water-holding capacity (WHC) of the longissimus muscle, shear force of the biceps femoris muscle, and iodine values and fatty acid composition of the i.m. and s.c. fat depots were determined. The percentage of fat in the longissimus muscle increased with live weight, and values for RA lambs were higher than those for L lambs. The WHC of meat from RA lambs was lower at 24 kg than at 12 or 36 kg slaughter weight. Live weight and breed had no effect on the shear force of the biceps femoris muscle. There was an increase in myoglobin concentration in the longissimus muscle with increased live weight in both breeds. The fatty acid content of s.c. and i.m. fat, which was not affected by breed, declined with the increase in slaughter weight. The polyunsaturated fatty acid content of the s.c. fat depot increased, whereas that of the i.m. fat depot decreased, with the increase in slaughter weight in both breeds. Subcutaneous fat had a higher content of heptadecanoic acid (17:0) than i.m. fat, and this increased with the increase in slaughter weight. In both depots, there was an increase in oleic acid (18:1) at 12 kg in RA lambs and at 24 kg in L lambs. In the s.c. fat depot, there was a progressive increase in linoleic acid (18:2) content with the increase in live weight in both breeds. There was a higher degree of unsaturation in the s.c. fat of RA lambs than in that of L lambs, which was reflected in the iodine value.     

Effects of sarcoptic mange on the reproductive performance of ewes and transmission of Sarcoptes scabiei to newborn lambs

In each of two experiments, the reproductive performance of ewes naturally infested with sarcoptic mange and of uninfested ewes was assessed in in-season natural breeding conditions (experiment I) or in out-of-season controlled breeding conditions (experiment II). A statistically significant difference was observed in the total lambs born per ewe (infested ewes, 1.2; controls, 1.6), in the liveborn lambs per ewe (infested ewes, 1.2; controls, 1.5) and in the lamb body weight per ewe (infested ewes, 3.33kg; controls, 4.53kg) under natural breeding conditions, as well as in the lamb body weight per ewe (infested ewes, 3.37kg; controls, 4.14kg) among ewes under controlled breeding conditions. No adverse effects were observed in the other reproductive indices, cycling rate, mating rate, return-to-oestrus rate, abortion rate, lambing rate and stillbirth rate. Sarcoptic mange was observed in the offspring of infested ewes after 30 days and in the offspring of uninfested controls 60 days after their birth.     

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...     

Effect of replacing barley with rice bran in finishing diet on productive performance and carcass characteristics of Afshari lambs

Thirty-five male Afshari lambs (3.5 months old), with an average weight of 35 kg were randomly assigned to one of five experimental treatments relating to optimal replacement level of rice bran in lamb finishing diets. The lambs were fed a milled concentrate (3 mm screen) diet supplemented with 15% (DM basis) chopped (5 cm length) lucerne hay and chopped (5 cm length) maize silage or wet (80% moisture) sugar beet pulp. Barley grain in the lambs’ diets was replaced by rice bran at either 0, 15, 30, 45 or 60% of the concentrate mixture on a dry matter basis. Results show that lambs fed 45 and 60% rice bran treatments weighed significantly less than those fed with 15 and 30% and control group (P < 0.05). Average daily gain in lambs fed with concentrate mixtures containing 45 and 60% rice bran were 33 and 47% lower than control, respectively (P < 0.05). Lambs that received diets containing 45 and 60% rice bran, had lower feed intake (P < 0.05) than other groups. Using rice bran in the finishing diet had no significant effect on dressing percentage, tail percentage, abdominal fat and visceral organ weights. These results suggest that barley can be replaced with rice bran up to 30% in the finishing diets of lambs without any adverse effect on lamb performance.     

Effect of gestation-lactation diet calcium and zinc levels and of parenteral vitamins A, D and E during gestation on ewe body weight and on lamb weight and survival

Data on ewe body weights and on lamb birth and weaning weights and survival rates were recorded on a total of 557 multiparous Rambouillet, Hampshire X Suffolk and Synthetic I (composite of Finnish Landrace, Rambouillet and Polled Dorset) ewes in two experiments started after the first trimester of gestation. In Exp. 1, a 2 X 2 factorial arrangement of treatments included all combinations of low (.24% in gestation and .48% in lactation), or high (.80%) dietary Ca and low (20 ppm) or high (74 ppm) dietary Zn. No effect of dietary Ca or Zn level and no Ca X Zn interaction with respect to number of lambs born or weaned, birth weight, weaning weight or survival rate of the lambs or body weight of the ewes was shown. Mean number of lambs born was 1.63 +/- .71 with a survival rate of 85.0 +/- .3% and a weaning weight (59 d) of 19.4 +/- 4.4 kg. Experiment 2 was a repeat of Exp. 1 except that two intramuscular injections of vitamins A, D and E (d 65 and 93 of experiment) were given to one-half of the ewes in each diet group. There was no effect of dietary Ca or Zn level or of vitamin administration on ewe body weight changes, number of lambs born (1.89 +/- .55), survival rate (86.6 +/- .3%), lamb birth weight 4.6 +/- 1.5 kg) or lamb weaning weight (23.2 +/- 7.2 kg). Blood plasma Ca, inorganic P and Mg concentrations of ewes in late pregnancy were unaffected by diet or vitamin injections.(ABSTRACT TRUNCATED AT 250 WORDS)     

Sheep performance under intensive continuous grazing of native grasslands of <Emphasis Type="Italic">Paspalum notatum</Emphasis> and <Emphasis Type="Italic">Axonopus compressus</Emphasis> in the subtropical region of the Highlands of Central Mexico

Liveweight gain was evaluated in tropical Dorper X Pelibuey lambs under intensive continuous grazing of native grasslands dominated by Paspalum notatum (PN) or Axonopus compressus (AC) in the subtropics of Central Mexico. Two trials were undertaken. Trial 1 lasted 12 weeks with 10 lambs (initial weight 18 +/- 2.57 kg, 3 months old) per treatment in 2002, and Trial 2 for 13 weeks with 8 lambs (initial weight 24.0 +/- 2.0 kg, 4 months old) per treatment. Lambs were weighed once per week, and liveweight change was estimated by linear regression over day of the experiment, using individual regression coefficients as unbiased estimates of daily liveweight change; analysed in a random block design. Lambs on Trial 1 gained 0.061 kg/lamb/day on PN and 0.047 kg/lamb/day on AC (P > 0.05) at an overall mean stocking rate of 25 lambs/ha. In Trial 2, liveweight gain was significantly larger in PN (0.060 kg/lamb/day) than on AC (0.043 kg/lamb/day) (P < 0.05), at a mean stocking rate of 21.5 lambs/ha. It is concluded that intensive continuous grazing of native grasslands in the subtropics of the highlands of Central Mexico enables moderate liveweight gains for weaned lambs during the rainy season; with better results in grasslands dominated by Paspalum notatum.     

甘肃高山细毛羊枯草季放牧与暖棚舍饲饲养对比试验

枯草期选甘肃高山细毛羊成年母羊180只,后备母羊38只,羔羊40只,进行为期171 d的放牧与舍饲对比试验。结果表明:试验组(暖棚舍饲)平均每只成年母羊、后备母羊和羔羊体质量分别增加5.1、9.8和6.9 kg,增幅为:11.72%、30.81%和32.86%;对照组(放牧)每只成年母羊、后备母羊和羔羊体质量分别平均下降7.3、5.0和1.0 kg;试验末,试验组成年母羊和后备母羊体质量极显著高于对照组(P0.01),试验组羔羊体质量显著高于对照组(P0.05)。羊毛长度试验组成年母羊、后备母羊和羔羊羊毛每只分别平均增长3.9、3.8和2.7 cm,试验组成年母羊和后备母羊比对照组提高10.4%和16.0%,羔羊比对照组降低11.2%,试验组和对照组差异不显著(P0.05)。试验组各年龄段产羊毛量分别达5.24、4.56和3.79 kg,比对照组分别提高60.24%、73.38%和49.80%,差异极显著(P0.01)。试验组纯收入分别为成年母羊5.35元/只,后备母羊45.65元/只,羔羊59.57元/只,对照组由于掉膘损失严重,成年母羊和后备母羊分别损失28.32和13.05元/只,羔羊收益29.3元/只。