Optimum dietary crude protein level for finishing Awassi lambs

Awassi is a multi-purpose sheep breed. Awassi lambs being finished are usually offered an 18% crude protein (CP) diet. The growth rate of Awassi lambs is lower than other meat breeds. Therefore, this high content of dietary CP is questionable. The objective of this study was to estimate the optimum CP level for finishing Awassi lambs. Fifty male Awassi lambs (23.0±1.2 kg) were fed five high concentrate isocaloric diets (10 lambs per diet) that contained 10, 12, 14, 16, and 18% CP in a totally mixed diets for 9 weeks using a completely randomized design. Lambs were fed twice daily, and feed offered and feed refusals recorded for each feeding. Individual lamb intakes were calculated using daily feed offered and feed refused averaged over the interval of the experiment. Digestibility estimates were measured by total fecal collection. Lambs fed diets that contained 10, 12, and 14% CP gained less weight than those fed the 16 and 18% CP diets (P<0.05). Dry matter and CP intakes increased (P<0.05) with increasing levels of dietary CP. No difference (P>0.10) was observed in feed-to-gain ratio between diets except for the diet that contained 10% CP (P<0.05) which had a lower ratio. Organic matter and CP digestibility were lowest in lambs fed the 10% CP diet. Results suggest that the optimum CP concentration is 16% and that any increase above this level will not result in any improvement in production.     

Physical,chemical and organoleptic properties of ram lamb carcasses from four fat-tailed genotypes

Physical, chemical and organoleptic characteristics of 20 ram lambs representing four fat-tailed genotypes Awassi, Red Karaman, Tushin and Awassi×Tushin were compared. After slaughter, carcasses were chilled at 5°C for 24 h, graded and evaluated. Then, the carcasses were dissected into wholesale cuts and longissimus dorsi (LD) and semimembranosus (SM) muscles were excised. The muscles were subjected to moisture, protein, fat and ash analyses and they were cooked to evaluate palatability. Cold carcass weight of RK and A×T lambs were heavier (P<0.01) than those of A and T lambs. A×T crossbreds had higher (P<0.05) cold dressing percentage and larger LD area than T lambs. However, the influence of genotype on the proportion of boneless retail cuts and marbling were not significant. Most of the proportions of wholesale cuts except for sirloin and flank were not affected by the genotype. The sensory panel found the meat from all genotypes acceptable (tenderness, juiciness, flavor and acceptability). Chemical composition of meat from the different genotype was not significantly different. The study reveals generally insignificant differences in chemical, physical and organoleptic properties between fat-tailed lambs with different genetic backgrounds.     

Dietary supplementation of plant bioactive-enriched aniseed straw and eucalyptus leaves modulates tissue fatty acid profile and nuggets quality of lambs

Utilization of low-input feed resources rich in plant bioactive compounds is a promising strategy for modulating the fatty acid profile in ruminant products. They manipulate microbes involved in rumen biohydrogenation and increase the accumulation of desirable fatty acids at the tissue level. Therefore, the present study was undertaken to assess the effect of dietary supplementation of aniseed straw and eucalyptus leaves on growth performance, carcass traits and fatty acid profile of finisher lambs. Thirty-six Malpura hogget were divided into three treatment groups of 12 each, reared individually in pen (1.6 m × 1.1 m) and fed ad libitum complete feed blocks made up of 55 parts concentrate, 5 parts molasses and 40 parts roughage. Roughage in control (Con) was 20 parts each of ardu (Ailanthus excelsa) leaves and oat (Avena sativa) straw. In test diets, that is, Con-as and Con-el, 10% aniseed (Pimpinella anisum) straw and Eucalyptus rudis leaves, respectively, were added by replacing 5% each of oat straw and eucalyptus leaves. The lambs were weighed weekly; and at the end of 3 months of feeding trial, the lambs were slaughtered to study the carcass traits, composition and product evaluation. Average daily gain (ADG) and DM intake (DMI) was higher (P < 0.05) in Con-as compared to Con and Con-el, while ADG and feed conversion ratio decreased (P < 0.05) by 29.4% and 36.4%, respectively, in Con-el compared to Con. Carcass traits showed lower (P < 0.05) loin eye area and chilling loss in the Con-el group compared to the Con-as and Con, and the total carcass fat compared to Con-as. However, the keeping quality of meat improved in both Con-as and Con-el which was reflected by lower (P < 0.05) thiobarbituric acid-reactive substances values. Nuggets prepared from Con and Con-as meat had superior (P < 0.05) sensory attributes with an overall palatability. Fatty acid profile of longissimus thoracis muscle showed lower (P < 0.05) atherogenic and thrombogenic indices in Con-as and higher (P < 0.05) in Con-el group. Moreover, in Con-as group, the proportion of C16:0 was lower (P < 0.05) and C18:3n-3 was higher (P < 0.05), but no effect was observed on the amount of conjugated linoleic acid (CLA; C18:2 c9t11). In case of adipose tissue, the content of CLA was higher (P < 0.05), and the ratio of n-6:n-3 was more nearer to desirable levels in Con-as group. Therefore, it can be concluded that aniseed straw is a promising feed supplement compared to eucalyptus leaves for improving meat quality and fatty acid profile in lambs.     

Effect of intramuscular injections of DL-α-tocopheryl acetate on growth performance and extracellular matrix of growing lambs

The effect of intramuscular injections of vitamin E on growth, carcass traits, intramuscular collagen (IMC) characteristics and decorin of growing lambs was studied. A total of 24 15-day-old Ile de France suckling male lambs were divided into two groups and weekly intramuscular injections of DL-α-tocopheryl acetate (control group, 0 IU; Vitamin E treatment, 150 IU) were given until the lambs were 64 days old. Lambs were individually weighted at 15, 29, 43, 57 days of age and at slaughter (71 days old). Dry matter intake and average daily weight gain were recorded. Hot and cold carcass weights were recorded and dressing percentages were calculated after dressing and chilling (2°C to 4°C for 24 h). Carcass shrink losses were calculated as well. Longissimus muscle (LM) pH and area were measured. The pelvic limb was removed and its percentage was calculated based on cold carcass weight. IMC and decorin analyses were assessed on LM and semimembranosus muscle (SM). DL-α-tocopheryl acetate treatment reduced (P<0.05) collagen maturity and increased (P<0.05) decorin in both LM and SM muscles of growing lambs, while it did not affect IMC content. In addition, vitamin E did not influence growth, carcass weight, dressing percentage, carcass shrink losses and area of LM but decreased (P<0.05) the pelvic limb percentage. The LM pH values were higher (P<0.05) in vitamin group than in control group. Furthermore, different IMC characteristics between the muscles (P<0.01) were apparent. Multiple intramuscular injections of DL-α-tocopheryl acetate influence extracellular matrix in lambs, which could affect meat tenderness.     

Garlic skin induces shifts in the rumen microbiome and metabolome of fattening lambs

Garlic (Allium sativum L.) and its constituents have been shown to modify rumen fermentation and improve growth performance. Garlic skin, a by-product of garlic processing, contains similar bioactive components as garlic bulb. This study aimed to investigate the effects of garlic skin supplementation on growth performance, ruminal microbes, and metabolites in ruminants. Twelve Hu lambs were randomly assigned to receive a basal diet (CON) or a basal diet supplemented with 80 g/kg DM of garlic skin (GAS). The experiment lasted for 10 weeks, with the first 2 weeks serving as the adaptation period. The results revealed that the average daily gain and volatile fatty acid concentration were higher (P < 0.05) in lambs fed GAS than those in the CON group. Garlic skin supplementation did not significantly (P > 0.10) affect the α-diversity indices, including the Chao1 index, the abundance-based coverage estimator value, and the Shannon and Simpson indices. At the genus level, garlic skin supplementation altered the ruminal bacterial composition by increasing (P < 0.05) the relative abundances of Prevotella, Bulleidia, Howardella, and Methanosphaera and decreasing (P < 0.05) the abundance of Fretibacterium. Concentrations of 139 metabolites significantly differed (P < 0.05) between the GAS and the CON groups. Among them, substrates for rumen microbial protein synthesis were enriched in the GAS group. The pathways of pyrimidine metabolism, purine metabolism, and vitamin B6 metabolism were influenced (P < 0.05) by garlic skin supplementation. Integrated correlation analysis also provided a link between the significantly altered rumen microbiota and metabolites. Thus, supplementation of garlic skin improved the growth performance of lambs by modifying rumen fermentation through shifts in the rumen microbiome and metabolome.     

Solar-dried citrus pulp as an alternative energy source in lamb diets: Effects on growth and carcass and meat quality

Twenty-seven Italian Merino male lambs, equally divided into three groups, were used to evaluate the effects of the dietary incorporation of citrus pulp dried by exploiting solar energy (solar-dried citrus pulp, SDCP) on growth and carcass and meat quality. The diet consisted of oat hay and concentrate, with a hay/concentrate ratio of 30/70. The concentrates of the SDCP-0, SDCP-30 and SDCP-45 groups were formulated to incorporate 0, 30 and 45% of SDCP, respectively, as partial replacement of cereal grain. The lambs were slaughtered after 80 days of feeding (at 150 days of age) and carcass and some meat quality parameters were measured. No significant differences were found in final live-weights and average daily gains among the groups. Lambs in the SCP-45 group showed impaired (P < 0.001) feed conversion efficiency, lower (P < 0.05) carcass weight and lower (P < 0.05) dressing percentage compared with the other two groups. The majority of SDCP-45 carcasses (88.9%) fell within the bis-grid EU system (light carcasses weighing ≤13 kg), while most SDCP-0 (66.7%) and SDCP-30 (77.8%) carcasses fell within the SEUROP system (heavy carcasses weighing >13 kg). The bis-grid EU carcass classification highlighted how all carcasses produced an ideal meat colour and fatness, while the SEUROP grid carcass classification showed good carcass conformation and optimal fatness in the SDCP-0 and SDCP-30 groups. Carcass compactness was found to be significantly higher (P < 0.05) in groups SDCP-0 and SDCP-30 compared to group SDCP-45. The histological dissection of the pelvic limb evidenced a higher (P < 0.01) adiposity in the SDCP-0 and SDCP-30 groups. Chemical analysis of meat did not differ significantly among the groups. Physical analysis of the meat showed higher (P < 0.05) redness value and higher (P < 0.05) chroma value in the SDCP-0 and SDCP-30 groups. Based on the results of the present study it may be concluded that SDCP can be incorporated in concentrate mixtures for fattening lambs at levels equal to 30% without adverse effects both in growth and slaughter performances as well as in carcass and meat quality and, at this replacement level, it appears also to be economically convenient.     

Effects of sire genotype on lamb performance at weaning in extensive sheep systems

A low finishing weight and poor carcass characteristics are major causes of lower incomes in extensive sheep flocks; however, the use of terminal sire crossbreeding would improve lamb performance and carcass traits under these conditions. The aim of this study was to evaluate sire breed effects on the performance of lambs born to Corriedale ewes in extensive sheep systems in Western Patagonia. A total of 10 Corriedale, 10 Dorset, nine Suffolk and seven Texel sires, 16 of which were under a genetic recorded scheme and 20 selected from flocks not participating in genetic improvement programmes, were used across six commercial farms for 2 successive years. Data were collected from 685 lambs of the four resulting genotypes. Overall, Corriedale lambs were 0.47 kg lighter at birth than crossbred lambs (P<0.001). Suffolk and Texel sired lambs required more assistance (P<0.01) at birth than Corriedale or Dorset sired lambs, with Suffolk sired lambs requiring the most assistance (8%). Ewes sired with Suffolk rams had larger (P<0.05) litters than ewes sired with Texel or Corriedale rams. Lamb live weight gain from birth to weaning was higher (P<0.001) in crossbred lambs compared with Corriedale lambs, therefore, crossbred lambs averaged 2.9 kg heavier BW (P<0.001) than Corriedale lambs. A significant sire breed x sire source interaction was detected for lamb live weight gain (P<0.05) and lamb live weight at weaning (P<0.01), showing that the heaviest lambs were from recorded sires, except for Suffolk crossbred lambs. Mortality rate to weaning was increased (P<0.05) in Suffolk cross lambs (31%), with Corriedale lambs showing the lowest (17%) mortality. Terminal sire breeds increased (P<0.001) cold carcass weight, with 13.8, 16.0, 15.2 and 14.9 kg for the Corriedale, Dorset, Suffolk and Texel sired lambs, respectively. Carcass length, kidney knob and channel fat, fat grade, grade rule and fat depth measurements were not affected by sire breed (P>0.05). Carcass conformation was higher in Texel sired lambs compared with Corriedale lambs (P<0.05), with Dorset and Suffolk sired lambs being intermediate. Crossbred lambs showed a greater (P<0.001) eye muscle than Corriedale. Commercial cuts were affected by sire breed, as a result of the Corriedale lambs being smaller and having lighter carcass than crossbred lambs. Significant improvement in lamb weights at weaning and carcass traits could be expected when using a terminal sire on Corriedale ewes in Western Patagonia. However, no advantages were detected with the use of recorded sires under these production systems.     

Growth performance,nutrient digestibility,blood parameters,and carcass characteristics by lambs fed an oregano and cobalt blend

Shifting ruminal fermentation via feeding a blend of oregano (Organum vulgare L.) essential oils and Co-lactate (EOC; Rum-A-Fresh, Ralco, Inc. Marshall, MN) could improve lamb growth and carcass performance. Eighteen Suffolk × Little Han Tail F1 male lambs (20.3 ± 0.23 kg BW and approximately 3 months old) were randomly assigned using a completely random design to one of three treatments. Treatments were (1) EOC0: basal ration without EOC, (2) EOC4: basal ration plus 4 g/d EOC, and (3) EOC7: basal ration plus 7 g/d EOC. Initial and 24 d BW was similar (P > 0.10), but at 48 and 72 d, lambs fed EOC7 demonstrated greater (P = 0.01) BW compared with EOC0 fed lambs, while lambs fed EOC4 were intermediate and similar (P > 0.05). Average daily gains (ADGs) for 0–24 and 0–72 d were greater (P < 0.05) for lambs fed EOC4 and EOC7 compared with lambs fed EOC0, while DM intake was similar (P > 0.10). Feed conversions for 0–24 d were improved (P < 0.02) for lambs fed EOC4 and EOC7 compared with lambs fed EOC0. However, 0–72-d feed conversions were greater (P < 0.01) for lambs fed EOC7 compared to lambs fed EOC0, with lambs fed EOC4 being intermediate and similar (P > 0.05). DM, NDF, and ADF digestibilities were similar (P > 0.10) among treatments, while CP digestibility was greater (P < 0.01) for lambs fed EOC4 and EOC7 compared with lambs fed EOC0. Carcass weight and dressing percentages were improved (P < 0.01) for lambs fed EOC7 compared with lambs fed EOC0 and EOC4. Head width was greater (P > 0.01) for lambs fed EOC7 compared with lambs fed EOC0 and EOC4, while rump width was greater (P > 0.01) for lambs fed EOC4 and EOC7 compared with lambs fed EOC0. Plasma triglyceride and cholesterol concentrations were lower (P < 0.05) for lambs fed EOC4 and EOC7 compared with lambs fed EOC0, while albumin, total serum protein, and glucose concentrations were greater (P < 0.05) for lambs fed EOC4 and EOC7 compared with lambs fed EOC0. Feeding an EOC blend as an alternative antibiotic growth promoter at 4 and 7 g/d linearly improved lamb growth performance, feed conversions, frame growth, carcass weights, dressing percentages, and immunity.     

Rumen fluid transplantation affects growth performance of weaned lambs by altering gastrointestinal microbiota,immune function and feed digestibility

Although rumen fluid transplantation (RT) has been developed to confer benefits for adult ruminants by altering gastrointestinal tract microbiota, the question remains whether RT can also benefit weaned lambs. Hence, in this study, thirty-eight pre-weaning lambs were randomly assigned to one of three treatment groups: control lambs (CON) received 25 ml of normal saline solution, and lambs in two RT groups received 25 ml of rumen fluid either from 3-month-old lambs (LT) or from one-year-old adult ewes (AT). The effects on their growth performance, nutrient digestibility, some blood parameters and gastrointestinal tract microbiota were monitored. There were differences (P < 0.05) in rumen bacterial composition between the groups at weaning, at 3 months and at 1 year. Rumen fluid transplantation decreased (P < 0.05) average daily feed intake, average daily gain in live weight and apparent digestibility of ether extract in the LT group, and it decreased (P < 0.05) apparent digestibility of NDF and ADF in the AT group. Rumen fluid transplantation also increased (P < 0.05) concentrations of serum immunoglobulin A in the AT group and increased (P < 0.05) serum concentrations of interleukin-6, interferon alpha and D-lactate in both LT and AT groups. Bacterial α-diversity in the rumen and rectum was not affected by RT (P > 0.05), but a bacterial community change was observed after RT, and the abundance of some dominant bacteria in both rumen and rectum changed after RT (P < 0.05). Analysis of correlations between the parameters indicated that the altered gastrointestinal microbiota and accelerated maturity of rumen microorganisms induced by RT caused some impairment of gastrointestinal integrity and immunity, which led to decreased feed intake, reduced feed digestibility and lower growth performance of the weaned lambs. In conclusion, rumen fluid transplantation altered the gastrointestinal microbiota causing adverse effects on feed intake, feed digestibility and growth performance of the weaned lambs.     

Growth,meat and feed efficiency traits of lambs born to ewes submitted to energy restriction during mid-gestation

The objective of this study was to evaluate the effects of the energy restriction of gestation of adult ewes from day 45 to day 115 on lamb live performance parameters, carcass and meat traits. In experiment I, dietary energy was restricted at 70% of the metabolizable energy (ME) requirements, after which ewes were re-fed ad libitum until lambing. In experiment II, dietary energy was restricted at 60% of the ME requirements, and ewes were re-fed to ME requirements until lambing. All ewes grazed together from the end of the restriction periods to weaning. Lambs were weaned and lot fed until slaughter. Feed intake, weight gain and feed efficiency were recorded, and body fat thickness and ribeye area (REA) were measured in the longissimus thoracis muscle. After slaughter, carcass weight and yield, fat depth, carcass and leg length, and frenched rack and leg weights and yields were determined. Muscle fiber type composition, Warner-Bratzler shear force, pH and color were determined in the longissimus lumborum muscle. In experiment I, energy restriction followed by ad libitum feeding affected lamb birth weight (P<0.05); however, no effects (P>0.05) were observed on later BW, REA, BF or carcass traits. Lambs born to non-restricted-fed ewes had higher (P<0.05) weight and yield of the frenched rack cut and their meat tended (P=0.11) to be tender compared with that of lambs from restricted ewes. The percentage of oxidative muscle fibers was lower for lambs born to non-restricted ewes (P<0.05); however, no effects of ewe treatment were observed on other muscle fiber types. For experiment II, energy restriction followed by ME requirements feeding, affected (P<0.01) pre-weaning live weight gain, weaning and final weights. Lambs from restricted ewes had higher (P<0.05) feed intake as % of leg weight and a trend to be less efficient (P=0.16) than lambs from unrestricted dams. Ribeye area and BF were not influenced by treatment. Treatment significantly affected slaughter weight, but had no effects on carcass yield and traits or on meat traits. The results obtained in both experiments indicate submitting ewes to energy restriction during gestation affects the performance of their progeny but the final outcome would depend on the ewe’s re-feeding level during late gestation and the capacity of the offspring to compensate the in utero restriction after birth.     

Effect of dietary sodium bicarbonate supplementation on fermentation characteristics and ciliate protozoal population in rumen of lambs

Effects of sodium bicarbonate (NaHCO₃) inclusion on rumen fermentation characteristics and ciliate protozoal population in high concentrate-fed lambs were studied. Twenty-four weaner (90 days old) Malpura lambs divided into four equal groups (G1, G2, G3 and G4) were fed basal (25:75 roughage and concentrate) diet (G1) or basal diet supplemented with 0.75% (G2), 1.50% (G3) and 2.25% (G4) sodium bicarbonate for 90 days. Daily dry matter (DM) intake and digestibility of organic matter (OM), crude protein (CP), gross energy and plane of nutrition were similar in all the groups while cellulose digestibility was higher in G4 than in G2 and G1. Ruminal pH increased (P<0.05) with increasing levels of dietary sodium bicarbonate. Concentrations of total volatile fatty acids (TVFA), total nitrogen and trichloroacetic acid-precipitable nitrogen (TCA-ppt.-N) were higher while ammonia nitrogen was lower in the rumen fluid of G4 and G3 than in G2 and G1. The number of total protozoa, Isotricha, Dasytricha, large and small spirotrichs were higher (P<0.01) in the rumen of G4 and G3 than in G2 and G1. Total live weight gain and average daily gain were also higher in lambs supplemented with sodium bicarbonate. It is concluded that sodium bicarbonate inclusion at the rate of 1.50% of total ration increased cellulose digestibility, ciliate protozoal number, ruminal pH and total nitrogen concentration resulting in improved growth of lambs maintained on high concentrate diet.     

Partial replacement of barley grain and soybean meal by fleabane (Conyza bonariensis) in diets of growing Awassi lambs

Effects of partial substitution of barley grain and soybean meal with fleabane (FB) Conyza bonariensis on growth performances and body compositions of 24 male local Awassi lambs were studied. All lambs were male with an average BW of 20.3 kg (s.d. = 2.0 kg) at the beginning of the experiment. Animals were randomly divided into four groups of six lambs each. Lambs in each group received individually their cereal–soybean-based total mixed rations with levels of FB: 0, 50, 100 and 150 g/kg dry matter (DM) diet, which replaced similar values of barley and soybean meal. All rations were isonitrogenous and isocaloric. The fattening experiment lasted 9 weeks, after which all lambs were slaughtered. The composition of nutrients in the C. bonariensis were 89.6%, 15.0%, 28.0%, 30.0% and 10% for organic matter, CP, NDF, ADF and lignin, respectively. At the end of the experiment, lambs fed 100 and 150 g FB/kg DM diets gained more weight (P < 0.05) than those fed the control and 50 g FB/kg DM diets. The DM intake was lower in lambs fed the highest level of FB compared with intakes of lambs in other treatments. Diet content of FB had significant effect (P < 0.05) on weights of empty body, carcass, gut and external (hide, head and feet) among all animals. However, FB had no effects on lambs’ thoracic organs (lungs and heart) and liver. Muscle, bone, omental and mesenteric fat, subcutaneous, intermuscular, pelvic and kidney fat weights (g/kg empty BW) were not affected by FB feeding. Carcass fat was decreased (P < 0.05) by the increase of FB. Total body fat was the same in all animals of the experiment.     

Rumen fermentation patterns and nutrient digestion in lambs fed cottonseed meal supplemental diets

Twenty crossbred 3–4-month-old male lambs of uniform body weight were used to assess the effect of raw and processed cottonseed (Gossypium) meals (CSM) on nutrient utilisation and rumen fermentation patterns. Lambs were assigned to five dietary treatments in a completely randomised design and fed isonitrogenous and isocaloric concentrate mixtures containing 30% deoiled groundnut cake (DGNC) (control), 40% of either raw, 45 min cooked, 1% calcium hydroxide (Ca(OH)₂) or iron (1 part free gossypol (FG):0.3 parts iron) treated CSM. The concentrate mixtures were fed to meet 80% of crude protein requirements (NRC, 1985) with ad libitum access to chopped maize hay (Zea mays). A metabolic trial of 6 days duration was conducted after 135 days of feeding, and rumen liquor was collected for 2 days at its end. Incorporation of 40% raw CSM resulted in reductions (P<0.01) in the digestibility of dry matter and organic matter in comparison to control fed lambs. Cooking and Ca(OH)₂ treatment of CSM improved digestibilities of these nutrients, to levels comparable to those in control fed lambs. The ether extract (P<0.05) and energy (P<0.01) digestibilities in lambs fed Ca(OH)₂ treated CSM were higher compared to those lambs fed raw CSM diets. Acid detergent fibre and cellulose digestibilities were lower (P<0.05) on cooked and iron treated CSM fed lambs. Retention of nitrogen and energy did not differ among diets. The digestible and metabolisable energy content of the Ca(OH)₂ treated CSM incorporated diet was higher (P<0.01) than the other CSM containing diets, but similar to DGNC containing ration. Rumen pH and total volatile fatty acid concentration was similar among diets, but NH₃–N was lower (P<0.05) on the cooked CSM diets versus the control. Feeding of lambs with raw CSM amounting to 17.9% of total dry matter intake (i.e. 303 mg FG intake per day) adversely affected utilisation of nutrients and rumen fermentation. This depression was alleviated to the greatest extent by 45 min cooking and 1% calcium hydroxide treatment. Iron treatment of CSM had little overall benefit.     

Sexual performance of Awassi ram lambs reared in different sex composition groups

The objective of this study was to evaluate the effect of sex composition of the group of lambs before puberty on later sexual performance in Awassi ram lambs. Thirteen Awassi ram lambs of the same age were raised in either all-male group (n = 7) or in a group mixed with females (n = 6) from weaning to puberty. Blood samples, body weights (BW) and scrotal circumferences (SC) of ram lambs were recorded between eight and 10 months of age. Sexual performance testing was performed at 9 months of age by individually exposing ram lambs to oestrous females on five occasions. Body weight and SC were greater (P < 0.01) in the all-male compared with the mixed group. Plasma testosterone concentrations were not influenced (P > 0.05) by treatment. Plasma testosterone concentrations were significantly correlated (P ≤ 0.05) with BW (r = 0.3) and SC (r = 0.4). No treatment effects were detected regarding bouts of leg-kicking. Bouts of anogenital sniffing, the frequency of mount attempts and mounting frequency were greater (P < 0.05) in the all-male group. Even though the frequency of raising the fat tail of females was similar between the two treatments, the mixed group tended to be (P = 0.08) more efficient in doing so than the all-male group (higher tail raising/mount). Results of the current study indicate that mixing groups of ram and ewe lambs before puberty may be insufficient to improve later sexual performance of ram lambs.     

Effect of milk replacer and rumen inert fat on growth and reproduction of Malpura ram lambs

The objective of this study was to assess the effects of milk replacer and rumen inert fat on growth, testicular development, puberty, semen production and sperm motion characteristics of ram lambs reared under intensive management in semi-arid climatic conditions. Seven-day-old male lambs of Malpura breed (n=20) were divided equally into two groups. Up to weaning, the lambs in G1 group (control) were fed concentrate, green khejri (Prosopis cineraria) leaves and cowpea (Vigna unguiculata) hay along with suckling of dams, whereas lambs in G2 group were fed reconstituted milk at 17 g/lamb per day for the 1st week and at 34 g/lamb per day from 2nd week in addition to the feed inputs given in G1. During post weaning, lambs in the G1 group were given control concentrate, whereas in G2 the control concentrate supplemented with 40 g rumen inert fat per kg of feed was offered along with dry pala (Zizyphus nummularia) and ardu (Ailanthus excelsa) leaves. BWs of lambs were recorded weekly up to 6 months of age. Ram lambs of both the groups were trained for semen collection at a weekly interval from the age of 5 months and simultaneously testicular measurements were recorded fortnightly. The feeding of milk replacer and rumen inert fat had positive (P<0.05) effects on BW, testicular length, testicular volume, semen volume, sperm concentration, mass motility, % motility, % rapid, medium or slow motile spermatozoa. However, no significant effect was observed on testicular breadth, scrotal circumference, age of puberty, sperm velocities and other CASA-derived parameters. The results of this study indicate that higher plane of nutrition in the form of milk-replacer feeding during preweaning and rumen inert fat-supplemented feed during the postweaning period to growing ram lambs enhances their growth, testicular development and semen quality.     

Effects of rumen-protected betaine supplementation on meat quality and the composition of fatty and amino acids in growing lambs

Rumen-protected betaine (RPB) can enhance betaine absorption in the small intestine of ruminants, while betaine can alter fat distribution and has the potential to affect the meat quality of livestock. Hence, we hypothesized that RPB might also affect the meat quality of lambs. Sixty male Hu sheep of similar weight (30.47 ± 2.04 kg) were selected and randomly subjected to five different treatments. The sheep were fed a control diet (control treatment, CTL); 1.1 g/day unprotected-betaine supplemented diet (UPB); or doses of 1.1 g/day (low RPB treatment; L-PB), 2.2 g/day (middle RPB treatment; M-PB) or 3.3 g/day (high RPB treatment; H-PB) RPB-supplemented diet for 70 days. Slaughter performance, meat quality, fatty acid and amino acid content in the longissimus dorsi (LD) muscle, shoulder muscle (SM) and gluteus muscle (GM) were measured. Compared with CTL, betaine (including UPB and RPB) supplementation increased the average daily weight gain (ADG) (P < 0.05) and average daily feed intake (P < 0.01) of lambs. Rumen-protected betaine increased ADG (P < 0.05) compared with UPB. With increasing RPB doses, the eye muscle area of the lambs linearly increased (P < 0.05). Compared with CTL, betaine supplementation decreased water loss (P < 0.05) in SM and increased pH₂₄ in the SM (P < 0.05) and GM (P < 0.05). Compared with UPB, RPB decreased water loss in the GM (P < 0.01), decreased shear force (P < 0.05) in the LD and SM and increased the pH of the meat 24 h after slaughter (pH₂₄). With increasing RPB doses, the shear force and b* value in the LD linearly decreased (P < 0.05), and the pH₂₄ of the meat quadratically increased (P < 0.05). Compared with CTL, betaine supplementation increased the polyunsaturated fatty acid in the GM (P < 0.05). Compared with UPB, RPB supplementation decreased the saturated fatty acid (SFA) content in the LD (P < 0.05) and increased the unsaturated fatty acids (UFA), mono-unsaturated fatty acids and UFA/SFA ratio in the LD (P < 0.05). Compared with CTL, the content of histidine in the LD increased with betaine supplementation. Compared with UPB, RPB supplementation increased the content of total free amino acids and flavor amino acids in the LD of lambs (P < 0.05). With increasing RPB, the isoleucine and phenylalanine contents in the LD linearly increased (P < 0.05). Overall, the data collected indicated that the meat quality of lambs (especially in the LD) improved as a result of betaine supplementation, and RPB showed better effects than those of UPB.     

Reproductive performance and milk yield in Awassi ewes following crossbreeding

The objective of this study was to evaluate the effect of crossbreeding Awassi ewes with either Charollais or Romanov sires, on pre-weaning lamb production as reflected by reproductive performance and milk production in the ewes. Two hundred and five, 3- to 6-year-old multiparous ewes of three breeds were allocated to three groups [Awassi (A; n = 56), F₁ Romanov × Awassi (RA; n = 78) and F₁ Charollais × Awassi (CA; n = 71)]. Upon lambing, ewes and their offspring were placed in a large pen in which they remained until the end of the trial. Body weight (BW) and body condition score (BCS) of the ewes and the BW of the lambs were recorded weekly from birth to weaning at 70 days of age. Milk production was recorded weekly from parturition to weaning. Pregnancy rates were not influenced by breed-type. Multiple births and the fecundity of ewes were greater (P < 0.05) in the RA group, compared to the A and CA groups—while the weaning percentage was similar between the breeds. Lamb birth and weaning weights were similar, while the kg lamb born per kg ewe lambed was greater (P < 0.05) in the RA group, compared to the CA group. The CA ewes recorded a higher BW (P < 0.01) and BCS (P < 0.01) than the other breed groups. Awassi ewes produced more milk (P < 0.01) throughout the observation period. Milk ash percentage was higher (P < 0.05) in the CA group, while the percentage of crude protein and dry matter was similar for the different groups. Results of the present study indicate that crossbreeding of Awassi ewes with Charollais and Romanov breeds decreased milk production in the progeny, without affecting lamb growth. The crossbreeding of Awassi with Charollais resulted in improved BW and BCS, while the crossbreeding of Awassi ewes with Romanov resulted in improved reproductive performance of the crossbreds. Crossbreeding Awassi ewes with exotic rams can thus be conducted to increase the number of lambs produced per ewe.     

Production efficiency and feeding behavior of Awassi lambs and Baladi kids fed on a high concentrate diet

Fifteen Awassi lambs and 15 Baladi kids (males, averaging 14.3 kg) were used to study the differences in feeding behavior and performance of sheep and goats fed a concentrate finishing diet (CP = 16 kg/100 kg DM, ME = 2.85 Mcal/kg DM) in a complete randomized design experiment lasting 60 days. Dry matter (DM) and organic matter (OM) intakes were significantly (P < 0.05) higher in lambs. Kids had higher (P < 0.05) apparent OM, crude protein (CP) and gross energy digestibilities. No significant (P > 0.05) differences were observed in apparent neutral detergent fiber (NDF) digestibility, eating, chewing and ruminating times. However, eating and ruminating times (as min/kg NDF intake) was significantly (P < 0.05) higher in kids. Final body weight and average daily weight gain were significantly (P < 0.05) higher in lambs while kids had significantly (P < 0.05) lower feed to gain ratio. Feed cost per kilogram weight gain for kids was better than that for lambs. Results demonstrated that Awassi lambs consumed more feed and grew faster than Baladi kids. However, kids were more efficient feed converters than lambs.     

Comparison of the behaviour of Awassi lambs in cafeteria feeding system with single diet feeding system

This study was carried out to compare behavioural activities of Awassi lambs in cafeteria feeding system with conventional feeding (control) that animals fed concentrate. Sixteen, 3-month-old male lambs were housed individually for 42 days. The main effect was on the feeding systems, cafeteria and control. Cafeteria lambs (n=8) were offered the main ingredients (barley, cotton seed meal (CSM), wheat bran and alfalfa straw), while control animals (n=8) were fed a single diet (48% barley, 22% cottonseed meal, 18% wheat bran, 10% alfalfa and 2% vitamin–mineral mixture; having 2467 Kcal ME and 161 g kg⁻¹) with the same main ingredients with slightly higher nutrient content for growth. Food and water intakes were recorded daily, while behavioural observations were recorded twice a week for a period of 1 h at 5 min intervals at 13:00, 16:00, 19:00, 22:00, 01:00, 04:00, 07:00 and 10:00 h after the initiation of daily feeding. After every 5 min, each lamb was monitored to determine its eating, ruminating, drinking, walking, standing, playing, resting and other activities.Cafeteria lambs selected a diet that matched their growth requirement as did control lambs. However, cafeteria lambs ate more (P<0.01). Cafeteria animals preferred cotton seed meal (42.4%) to barley (32.9%) without changing their water intake, final live weight and daily gain (P>0.05). Cafeteria lambs also had higher rates of eating (22% versus 19%, P<0.01), ruminating (24% versus 23%, P>0.05) and resting (29% versus 23%, P<0.01) than the control lambs. On the other hand, cafeteria lambs spent less time standing (19% versus 25%, P<0.01) and walking (1.5% versus 2.1%, P<0.01) compared with control animals. In conclusion, cafeteria lambs selected a diet that matched their presumed biological (behavioral and nutritional) needs without changing their growth performance.     

Serum metabolomic fingerprints of lambs fed chitosan and its association with performance and meat quality traits

Chitosan (CHI) is a natural biopolymer with antimicrobial, anti-inflammatory, antioxidant and digestive modulatory effects, which can be used in the ruminant diet to replace antibiotics. The aim of this study was to evaluate the effects of CHI on lamb growth traits, nutrients digestibility, muscle and fatty deposition, meat fatty acid (FA) profile, meat quality traits and serum metabolome. Thirty 30-month-old male lambs, half Suffolk and half Dorper, with an average BW of 21.65 ± 0.86 kg, were fed in a feedlot system for a total of 70 days. The lambs were separated into two groups according to the diet: the control (CON) group which received the basal diet and the CHI group which received the basal diet with the addition of CHI as 2 g/kg of DM in the diet. Lambs supplemented with CHI had a greater (P< 0.05) final BW, DM intake, final body metabolic weight (P< 0.05) and lower residual feed intake than the CON group. Animals fed CHI had a greater (P< 0.05) starch digestibility at 14 and 28 days, average daily gain at 14, 42 and 56 days, greater feed efficiency at 28 days and feed conversation at 14 and 42 days in feedlot. Most of the carcass traits were not affected (P> 0.05) by the treatment; however, the CHI supplementation improved (P< 0.05) dressing and longissimus muscle area. The treatments had no effect (P> 0.05) on the meat colour and other quality measurements. Meat from the CHI-fed lambs had a greater concentration (P< 0.05) of oleic-cis-9 acid, linoleic acid, linolenic-trans-6 acid, arachidonic acid and eicosapentaenoic acid. According to the variable importance in projection score, the most important metabolites to differentiate between the CON and the CHI group were hippurate, acetate, hypoxanthine, arginine, malonate, creatine, choline, myo-inositol, 2-oxoglutarate, alanine, glycerol, carnosine, histidine, glutamate and 3-hydroxyisobutyrate. Similarly, fold change (FC) analysis highlighted succinate (FC = 1.53), arginine (FC = 1.51), hippurate (FC = 0.68), myo-inositol (FC = 1.48), hypoxanthine (FC = 1.45), acetate (FC = 0.73) and malonate (FC = 1.35) as metabolites significantly different between groups. In conclusion, the present data showed that CHI changes the muscle metabolism improving muscle mass deposition, the lamb’s performance and carcass dressing. In addition, CHI led to an alteration in the FA metabolism, changes in the meat FA profile and improvements in meat quality.