Dorper Lambs Research Articles

Influence of Dorper lamb development from birth to 120 days of age on clinical and echocardiographic parameters

The expansion of the sheep model in research represents an attractive and economically beneficial academic reason for investigations in sheep echocardiography. The present study aimed to evaluate the clinical and echocardiographic parameters in Dorper lambs during the developmental period. Emphasis was placed on the use of the species in translational research for the echocardiographic diagnosis of congenital heart diseases, which can contribute to improvements in interventionist techniques. Ten Dorper lambs were evaluated at the following time points: 24 h after birth and 7, 14, 21, 30, 60, 90 and 120 days of age. Clinical parameters were compiled, and echocardiogram records were obtained without sedation. Rectal temperature was lower on the first day compared to the others. From 21 days of life, there was a reduction in HR, with differences between time points. Mean and systolic blood pressure differed, with the highest values at 90 and 120 days of age. The thickness of the interventricular septum in diastole (IVSd) increased as age progressed, with the highest value at 120 days of age, and the same occurred for LVIDd (left ventricle internal diameter in diastole), LVFWd (left ventricular free wall thickness in diastole), IVSs (interventricular septum thickness in systole), LVIDs (left ventricle internal diameter in systole) and LVFWs (left ventricular free wall thickness in systole). There were differences in the size of the LA, Ao and LA/Ao ratio, which were greater at 90 days and 120 days of age. Echocardiographic changes accompany the development of lambs, where changes in echocardiographic parameters are evident with advancing age. The echocardiographic measurements in lambs obtained in the present study are similar to those in newborns.

283 Quercetin Antagonizes Tall Fescue Toxicosis-Induced Cardiovascular Toxicity in Lamb (Ovis Aries) via Modulating PGC-1α Mediated Mitochondrial Biogenesis

Abstract Quercetin is a natural flavonoid with a higher antioxidant capacity and anti-inflammatory. Tall fescue [Schedonorus arundinaceus (Schreb.) Dumort; E+] is perennial cool-season grass for grazing livestock in North America. Fescue infected with the endophyte (Neotyphodium coenophialum) produces chemicals toxic to livestock. However, the impact of quercetin on alleviating fescue toxicosis has received only limited attention. The objective of this experiment was to investigate the mitigation effect of quercetin on fescue toxicosis-induced cardiotoxicity of lambs. A total number of 24 Dorper lambs were randomized to four groups (n = 6 per group) and grazed tall fescue seed for 42 days. The results indicated that quercetin treatment alleviated fescue toxicosis induced cardiovascular histopathology injury (Fig 1), inhibited the increased trend of creatine kinase activities, and serum prolactin concentrations (Fig 2). Meanwhile, quercetin mitigated fescue toxicosis-induced cardiovascular oxidative damage by decreasing MDA and H2O2 contents, increasing antioxidant enzymes (T-SOD, Cu-Zn SOD, CAT, and T-AOC) activities (Fig 3). Quercetin evidently enhanced fescue toxicosis-induced down-regulation of phase I, II, and II detoxification gene expression to relieve oxidative damage (Fig 4-6). Moreover, quercetin triggered the NF-kB signaling pathway to ameliorate fescue toxicosis-induced cardiovascular inflammation (Fig 7-9). Quercetin attenuated cardiac mitochondrial impaired via Parkin/PINK modulated mediated mitophagy and PGC1-α mediated biogenesis (Fig 10-13). Collectively, our findings demonstrated that quercetin explicated potential protection against fescue toxicosis-induced cardiovascular toxicity.

Cost-effectiveness of Total Mixed Ration with Varying Crude Protein Levels for Feeding Dorper Lambs for Human Consumption

The demand for food consumption had increased by 60% due to the increase of human population, resulting in an increasing demand for sheep meat. High cost of imported feed had restricted the growth of the sheep industry. Hence, the objective of this study was to evaluate the cost-effectiveness of feeding total mixed ration (TMR) in the form of creep feed (CF) and growing ration (GR) to Dorper lambs compared to the control (CON) group fed with farm routine diet consisted of Napier grass and commercial pellet. Two (2) experimental phases were conducted, i.e., Phase I (CF) and Phase II (GR), which consisted of twenty (20) Dorper lambs with five (5) lambs in each group. The CF and GR consisted of constant metabolize energy (ME) (11 MJ/kg DM ME). The crude protein (CP) (%) in CF was varied at 14, 16, 18 and 20 for CON 14, CF 16, CF 18 and CF 20 respectively, whereas the CP (%) in GR was varied at 11, 14, 16 and 18 for CON 11, GR 14, GR 16 and GR 18 respectively. The cost of feed/kg gain (RM/kg) of CON 14 (1.63) and CF 18 (1.97) was significantly lowered (p<0.05) than CF 20 (3.35) whereas, GR 16 (8.94) was significantly lowered (p<0.05) than CON 11 (22.92) and GR 18 (23.99). This finding revealed that feeding local feed ingredients in TMR form, resulting in low feeding cost and subsequently higher economic returns. It can be concluded that feeding 18% CP (CF 18) and 16% CP (GR 16) were efficient to enhance the growth performance of pre-and post-weaning Dorper lambs respectively.

Quality of Santa Inês × Dorper sheep meat submitted to different levels of inclusion of sunflower cake

Aim of study: To evaluate the physicochemical and sensory quality of meat from Santa Inês × Dorper lambs fed diets with increasing levels of sunflower cake. Area of study: Rio Grande do Norte (Brazil). Material and methods: Twenty-four castrated lambs (initial weight of 18.9 ± 2.17 kg) were distributed in a completely randomized design with four treatments (0, 5, 10 and 15% sunflower cake in diet) with six repetitions and kept in confinement until reaching the average body weight of 32.1 ± 2.6 kg. The Longissimus lumborum muscle was used for proximate composition and physicochemical analyzes, and the Semimembranosus muscle was used for pH (after 24 h of slaughter) and sensory analysis assays. Main results: The increasing levels of sunflower cake did not affect the composition or physicochemical properties. Sensory analysis also did not reveal significant differences in meat obtained from animals in different diets. Principal Components Analysis indicated that juiciness, color, odor and flavor were positioned opposite to protein, texture, and ash. Research highlights: The use of sunflower cake in diets for crossbred sheep Dorper × Santa Inês as soybean meal and corn replacer, up to 15% inclusion of soybean meal and corn, does not affect the proximate composition, physicochemical or sensory characteristics of the meat.

Qualitative profile of meat from lambs fed diets with different levels of chitosan. Part II

Chitosan has the potential to modulate the rumen fermentation. This study aimed to evaluate the physicochemical composition, centesimal composition, and fatty acid profile of meat from feedlot lambs fed diets containing increasing levels of chitosan. Sixty crossbred Santa Inês × Dorper lambs with an average body weight (BW) of 23.6 ± 2.2 kg were distributed into three treatments (0, 136, and 272 mg/kg of BW), in a completely randomized design. The use of chitosan in the diets did not influence (P > 0.05) feed intake, body weight gain, feed conversion, loin-eye area, subcutaneous fat thickness, cooking loss, shear force, or the meat color. However, chitosan affect linearly the meat pH0 h (P = 0.022). Furthermore, the addition of chitosan of 136 mg/kg BW in the diet leads to higher contents of fatty acids C18:1 c11 (P = 0.012), C18:1 c12 (P = 0.015), C18:1 c13 (P = 0.008), and C18:1 t11 (vaccenic acid) (P = 0.034), resulting in high levels of unsaturated fatty acids in the Longissimus lumborum muscle, indicating improvement in the quality of meat from feedlot lambs related to human health.

Effect of Dehydrated Bovine Colostrum upon Immunity and Development of Dorper Lambs

Background: Ruminants, during the newborn stage, are considered as agammaglobulinemic (calves and buffalos) or hypogammaglobulinemic (kids and lambs), where the colostrum intake is important for the decrease of illness incidence, an adequate development and a low peripartum mortality. The aim was to evaluate the use of dehydrated bovine colostrum as an alternative to natural ovine colostrum upon de development and immunity of Dorper lambs. Methods: A total of 35 lambs, divided in two groups, one (CN; n=17) fed with natural colostrum directly from the mother, the second (CB; n=18) fed with a colostrum substitute based on dehydrated bovine colostrum, were used. Result: The colostrum quality was better for the CN group regarding lipids, CP, density, solids and fat when compared to the CB (p less than 0.05). Glucose levels were higher in the CN than the CB 24 h after colostrum administration (116 mg/dl and 97 mg/dl, respectively; p less than 0.05). There were no diarrheas or respiratory illnesses in lambs from both groups at 24 h after birth (p greater than 0.05). Maybe, the use of bovine dehydrated colostrum transfers a similar immunization than natural colostrum, which generated a low incidence of respiratory and metabolic illnesses and a good body development.

O efeito de probióticos fúngicos adicionados a uma dieta rica em grãos no trato gastrointestinal de ovinos

Abstract This study aimed to evaluate the microbiological and physicochemical characteristics of the ruminal fluid and histological characteristics of the gastrointestinal tract (GIT) of sheep on a high-grain diet containing the probiotic fungi Aspergillus terreus and Rhizomucor spp. The study included four treatment groups (without probiotic, with Rhizomucor spp., with Aspergillus terreus, and with a mixture of both fungi), and two types of corn (ground/whole), in a Completely Randomized Design (CRD) arranged in 4 x 2 factorial design. Santa Inês x Dorper lambs were housed in eight pens with five lambs each for 75 days. Rumen fluid was collected to study the rumen microbiological profile, macroscopic characteristics, ammonia nitrogen concentration, and microbiological activity. In addition, GIT samples were taken for histological analysis. Fluid analyses showed that the animals presented a low acidosis index. The samples presented a predominantly aromatic odor and blackish-brown color, indicating a neutral pH and high microbial activity. The rumen pH differed (P < 0.05) according to the level of processed corn consumed, being higher for ground grain corn (GGC). There was no difference for any of the microbiological communities analyzed (P > 0.05) (Lac+ and Lac- bacteria, fungi, yeasts, and protozoa). Six genera of facultative anaerobic fungi were identified in 15 observations. Cladosporium spp. was the most prevalent genus (46.66%), followed by Aspergillus spp. (26,66%). The width of the base of rumen papillae showed significant correlation being greater for GCG (P < 0.05) with Rhizomucor and for the control (P < 0.05). The rumen fluid of sheep on a high-grain diet with added Aspergillus terreus and Rhizomucor spp. showed no microbiological and physicochemical changes.

Histopathological Effects of Different Levels of Palm Kernel Cake Fed to Dorper Lambs

Palm kernel cake (PKC) is a nutrient-rich by-product of oil mills that contained a high concentration of copper (Cu) among other minerals elements. The higher dietary concentration of Cu was reported to impair some physiological functions in some breeds of sheep due to Cu toxicity. Hence, this study was aimed to investigate the histopathological effects of PKC based diet on vital organs of Dorper lambs. Fifteen male Dorper lambs (8 month-old) were randomly assigned to three treatment groups. Lambs were fed with a diet supplemented with different levels of PKC based on dry matter (DM) (PKC 750 gm kg-1 DM, PKC 700 gm kg-1 DM, and PKC 650 gm kg-1 DM) for 120 days. At the end of the experiment, all the lambs were slaughtered, liver, kidney, and testis samples were examined for gross pathological lesions. Microscopic examination showed that the liver of PKC75 group animals was histologically normal. However, cell hepatocyte abnormality was observed in PKC70 and PKC65 groups. No clinical symptoms or severe histological lesions were noticed in the kidney and testis of all groups. Therefore, the histomorphological normal organs observed indicated the PKC contents provided detoxification and immune defense in male lambs.

Productive characteristics of feedlot Santa Inês and Dorper lambs: intake, digestibility, feeding behavior, performance, carcass traits, and meat quality.

This study aimed to evaluate the intake, digestibility, feeding behavior, performance, carcass traits, and meat quality of feedlot Santa Inês (locally adapted breed) and Dorper (transboundary breed) lambs. Twenty non-castrated lambs were used (10 from the Santa Inês genetic group and 10 Dorper), with approximately 3months of age and an initial body weight of 22.95 ± 2.1kg (mean ± standard deviation), distributed in a completely randomized design. Nutrient intake and digestibility, feeding behavior, and liver metabolism enzymes were similar (P > 0.05) between genetic groups. Dry matter (DM) feeding and ruminating efficiency were higher (P < 0.05) in the Santa Inês genetic group. There was also no difference (P > 0.05) in the subjective evaluation and morphometric measurements. Genetic groups showed differences and trend to differences (P < 0.05) in performance and commercial cuts. The physicochemical characteristics, centesimal composition, and sensory attributes of the Longissimus lumborum muscle did not differ between the genetic groups (P > 0.05). The Santa Inês genetic group showed higher feeding efficiency and productive parameters when compared to Dorper lambs. Therefore, Santa Inês lambs have greater potential for meat production than Dorper lambs, when kept in the same breeding system as the feedlot.

Effect of Silage Diet (Sweet Sorghum vs. Whole-Crop Corn) and Breed on Growth Performance, Carcass Traits, and Meat Quality of Lambs.

Simple SummaryThe increasing demand for better sensory characteristics, nutritional quality, and functional attributes of meat products that are beneficial to human health is stimulating the consumer market. Diet and breed directly affect ruminant carcass traits and meat quality. Therefore, this research aimed to evaluate the effects of silage diet and breed on growth performance, carcass traits, and meat quality of lambs. The lamb breed influenced fewer variables of growth performance and carcass characteristics compared to diet, and the lambs fed the sweet sorghum silage diet had higher nutritional quality meat than lambs fed the whole-crop corn silage diet.Diet and breed directly affect ruminant carcass traits and meat quality. Therefore, this research aimed to evaluate the effect of silage diet and breed on growth performance, carcass traits, and meat quality of lambs. A total of 28, 3–4 months old female lambs consisting of 14 Dorper lambs (DP) and 14 Thin-tailed Han lambs (TH) were allocated in a 2 × 2 factorial design and offered two experimental diets (sweet sorghum silage: SS; whole-crop corn silage: WS) for 90 days. Lambs fed the WS diet had a higher growth performance (p < 0.01), intramuscular fat content (p < 0.05), and bright meat color (p < 0.01) than lambs fed the SS diet. The lambs fed the SS diet showed a higher polyunsaturated fatty acid (PUFA) content than the lambs fed the WS diet (p < 0.01); there was no significant difference in growth performance and carcass characteristics between DP and TH lambs (p > 0.05). The meat of the DP lambs showed lower values of initial pH, shear force, lightness (L*), redness (a*), and saturated fatty acid (SFA) content (p < 0.05). The lamb breed influenced fewer variables of growth performance and carcass characteristics compared to the diet. The lambs fed the SS diet had higher nutritional quality meat than lambs fed the WS diet.

SIMPLE LINEAR AND MULTIPLE REGRESSION ANALYSES OF MORPHOLOGICAL TRAITS ON BODY WEIGHT IN FEMALE DORPER SHEEP LAMBS

Regression is a very influential statistical technique that uses independent variables to describe the dependent variable. The present study was performed to determine the best-fitted model from different regression techniques to predict body weight (BW) from morphological traits viz. heart girth (HG), rump height (RH), body length (BL), withers height (WH) and sternum height (SH). Twenty-eight female Dorper sheep lambs at birth were used for data collection. The simple and multiple regression were used for data analysis. The coefficients of determination (R2) and mean square error (MSE) were used to determine the best-fitted regression model. The results indicated that in simple regression the best fitted regression model for estimation of BW in female Dorper lamb was the model including BL (R2 = 0.79, MSE = 1.43), in multiple regression, the best fitted regression model for estimation of body weight in female Dorper lamb was model including HG, RH, BL, WH, SH (R2 = 0.89, MSE = 0.90) in the study. The results of simple regression suggest that BL can truly estimate the body weight in female Dorper sheep lambs. Multiple regression findings suggest that two or more morphological traits can truly estimate body weight in the female Dorper lambs. The study will help the farmers to accurately predict the body weight of the Dorper sheep lambs using the morphological traits.

PSXIV-21 Performance of hair lambs maintained on stockpiled permanent pasture mixed with Cleome gynandra L. at multiple stocking densities

Abstract Stockpiled forage may extend the grazing season for sheep, reducing feeding costs. Additionally, internal parasites are a problem in sheep managed under grazing conditions. Plants high in phenolic compounds have potential to reduce parasite problems. Cleome gynandra is one such plant that has traditionally been used to treat worms in humans. Thirty-six Katahdin × Dorper lambs (38.8 ± 0.7 kg) were used to investigate the effect of stockpiled forages on lamb performance at different stocking densities: (i) 23 lambs/ha (LOW), (ii) 46 lambs/ha (MED), and (iii) 92 lambs/ha (HIGH). To test C. gynandra for anthelmintic properties, lambs were assigned to (i) permanent pastures (PP), and (ii) PP inter-seeded with C. gynandra (CL). The LOW lambs had the highest ADG (83.8 ± 10.5 g/day), MED lambs were intermediate (48.4 ± 11.6 g/day) and HIGH lambs were lowest (11.0 ± 10.6 g/day; P &amp;lt; 0.001). Lamb BCS did not differ between stocking densities or pasture types (P &amp;gt; 0.10). Fecal egg counts did not differ (P &amp;gt; 0.10) between pasture treatments. In conclusion, stockpiled forages may extend the grazing season for yearling lambs in Southern California. The lack of effect on parasite egg counts may be attributed to grazing C. gynandra at mature stage when nutritional and medicinal values were at their lowest. Future research can clarify the economics of grazing stockpiled forages for sheep at different stages of production, and nutritional effect of C. gynandra on carcass quality.

Nutrient intake, growth performance and nutrient digestibility of pre- and post-weaning Dorper lambs fed varying crude protein level.

The objective of the present study was to investigate the effect of varying crude protein (CP) levels on intake, growth performances and nutrient digestibility of Dorper lambs at pre- and post-weaning period. Twenty lambs at 7days old with an initial body weight of 2.91kg were individually penned and randomly assigned into four (4) dietary groups using a randomised complete block design. In Trial I, pre-weaning lambs were fed with creep feeding (CF) diet containing 14% crude protein (CP) as a control diet (CON14), 16% (CF16), 18% (CF18) and 20% (CF20) of CP for 84days. Following Trial 1, the animals were fed with a growing ration (GR) diet for 96-day feeding trial. The diets consisted of 11% CP as a control diet (CON11), 14% (GR14), 16% (GR16) and 18% (GR18) of CP. The water was available ad libitum and the feed intake was measured daily by the difference of feed offered and refused. The increase of CP level resulted in a linear increase of dry matter intake (DMI), nutrient intake and average daily gain (ADG) in pre- and post-weaning lambs. The DMI (g/day) of lambs fed with CF20 (1059.92) was significantly higher (p < 0.05) than CON14 (605.30), but it did not differ significantly with CF16 (866.80) and CF18 (680.40). Besides, the DMI (g/day) of lambs fed GR18 was found significantly higher than CON11 and GR16. In pre- and post-weaning lambs, there was a quadratic effect of increased CP level on the ADG. The ADG (g/day) of pre-weaning lambs fed with CF18 (247.86) and CF20 (251.28) were not significantly different (p > 0.05) compared to those fed with CF16 (217.95). For post-weaning lambs, GR16 had significantly higher ADG than CON11 (43.14), but it was no difference with GR14 (72.94) and GR18 (69.41). However, increased CP level resulted in linear increase of DM, ash, organic matter (OM) and CP digestibility. The present finding suggested that the optimum CP level for pre- and post-weaning Dorper lambs in Malaysia was 16% and 14%, respectively.

Subcutaneous fat thickness at slaughter in castrated and non-castrated Santa Inês and Dorper lambs and its influence on meat and carcass quality

The objective of this study was to evaluate the carcass characteristics and meat quality of castrated and non-castrated Santa Inês and Dorper lambs, finished in confinement and slaughtered with different subcutaneous fat thickness (SFT), which was evaluated using in vivo ultrasound. Sixty-nine male lambs from two genetic groups were used - 34 Santa Inês and 35 Dorper. Dorper lambs showed superior conformation and finishing, 22% and 15.73%, respectively, compared to that of the Santa Inês lambs. The lambs were classified and slaughtered according to the following criteria: intended subcutaneous fat thickness close to 0 mm, close to 3 mm and close to 6 mm. Measurements were taken of the longissimus lumborum muscle in the region between the 12th and 13th ribs on the left side of the animal. Dorper lambs deposited more fat than Santa Inês lambs, and when slaughtered with the intended thickness of subcutaneous fat of 6 mm, they presented 7.34 mm fat thickness made in the muscle, while 3.61 mm was observed in Santa Inês lambs with the same age and confinement period. The meat became darker, less reddish, and less yellow at subcutaneous fat thickness (SFT) between 0 and 6 mm. The measurement of SFT using the ultrasound showed a high positive correlation with the fat thickness measured in the muscle with a caliper (MFT), demonstrating the possibility of using this method in vivo for accurate prediction of MFT. Slaughter of lambs with 3 mm of subcutaneous fat is recommended and is enough to guarantee a quality standard for both carcass and meat.

Effects of alternative energy and protein sources on performance, carcass characteristics, and meat quality of feedlot lambs

The aim of this study was to evaluate the effects of replacing ground corn with crude glycerin and soybean meal by cottonseed cake, in association or not, on digestibility and intake of dietary nutrients, performance, carcass characteristics and meat quality of feedlot lambs. Thirty-two non-castrated crossbred 1/2 Santa Inês x 1/2 Dorper lambs, with an average body weight of 18.52 ± 3.24 kg (mean ± standard deviation) and with 3 months of age were distributed in a randomized complete block design, into four treatments and eight replicates per treatment, in a 2 × 2 factorial scheme. Four experimental diets were tested with different sources or combinations of energy and protein ingredients, respectively, in the concentrate: 1) ground corn + soybean meal; 2) ground corn and cottonseed cake; 3) crude glycerin and soybean meal; 4) crude glycerin and cottonseed cake. There was an interaction between the energy and protein sources in ether extract intake and total digestible nutrients digestibility (P < 0.01). There was an interaction between the energy and protein sources in the total weight gain (P = 0.03), hot (P = 0.03) and cold (P = 0.04) carcass weights, and shear force (P = 0.29). The inclusion of crude glycerin decreased (P = 0.01) the dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fiber (NDF), and non-fibrous carbohydrates (NFC) intakes, and the apparent digestibilitis of OM, NDF, and NFC (P < 0.05). Crude glycerin decreased the amount of retained nitrogen (P = 0.02), lower final weight (P < 0.01), average daily gain and cold carcass yield. An increase ocurred in the NDF intake (P < 0.05) when lambs were fed diet with cottonseed cake and a decrease (P < 0.01) in the digestibilities of DM, OM, CP and NDF. The replacement of 100% of ground corn by crude glycerin, with low purity, is not recommended in diets for feedlot lambs, because it decreases animal performance. In contrast, the total replacement of soybean meal by cottonseed cake can be used in diet for lambs, without causing damage to the performance and meat quality.

Impact of heat stress on the growth performance and retail meat quality of 2nd cross (Poll Dorset × (Border Leicester × Merino)) and Dorper lambs

The present study investigated the impact of heat stress and genetics on lamb growth performance and meat quality. Forty-eight Dorper and 2nd cross [Poll Dorset×(Border Leicester×Merino)] lambs (38--42kg; 4-5months old) were allocated to either thermoneutral [TN; 18-21°C, 45-55% relative humidity (RH)], or heat stress (HS; 28°C-38°C, 40-60% RH) conditions in a 2×2 factorial design for 2weeks. Compared with 2nd cross, Dorper lambs had a lower respiration rate (RR) and rectal temperature (RT), and exhibited less decline in body weight under HS. 2nd cross lambs showed a higher body weight gain than Dorpers under TN conditions. HS increased a* and chroma of the Longissimus thoracis et lumborum (LTL) from 2nd cross lambs over 10days of display, but had no impact on Dorper LTL. In conclusion, Dorpers showed higher heat tolerance compared with 2nd cross lambs during the 2weeks HS.

Macromineral requirements for gain of Dorper lambs with differences in residual feed intake and raised in Brazilian semiarid

The aim of this study was to determine the net requirements of calcium (Ca), phosphorus (P), magnesium (Mg) and sulfur (S) for gain of high or low residual feed intake (RFI) Dorper lambs confined in full sun or shade. Sixty-four intact male Dorper lambs with an average initial body weight (BW) of 17.8 ± 2.43 kg and an average age of 70 ± 10 days were confined for 40 days to separate them into two groups (high or low RFI). Thereafter, a group of 4 animals (2 high RFI and 2 low RFI) were slaughtered to estimate initial empty body weight (EBW) and body composition of animals slaughtered at the end of the experiment. The 60 remaining lambs were distributed in a randomized block design, with a 2 × 2×3 factorial scheme, with two feedlot environments (full sun or shade, 30 animals in each), two groups of feed efficiency (high RFI or low RFI, 30 animals in each) and different levels of concentrate (30, 45 and 60 %), with 5 repetitions in each interactive treatment. The animals from each feedlot environment and from each RFI were distributed in three dietary treatments with different levels of concentrate to have different body compositions necessary to determine their macromineral requirements. The animals were confined for 60 days until slaughter. Neither RFI nor feedlot environment affected the net macromineral requirements for gain of Dorper lambs (P > 0.05). There was a decrease in net Ca, P and S requirements as fasting BW (FBW) increased from 20 to 40 kg (P < 0.05). However, the net requirements of these macrominerals for gain increased as average daily gain (ADG) increased from 100 to 300 g/day (P < 0.05). In contrast, the net Mg requirement for gain increased as both FBW and ADG increased (P < 0.05). The results showed that there was no significant effect of RFI and shade environment on the net requirements of macrominerals for weight gain of Dorper lambs. Possible differences could be in the dietary level or in the maintenance level. Therefore, further studies are needed to assess the effect of RFI and shade environment on the mineral requirements of lambs.

Digestibility of starch, ruminal protozoa count, and blood parameters of Dorper lambs with differences in residual feed intake

This study aimed to evaluate the digestibility of starch, ruminal protozoa count and blood parameters of sheep with high or low residual feed intake (RFI) fed different levels of concentrate in the diet. Sixty male Dorper lambs with a mean initial body weight of 17.8 kg ± 2.43 were confined for 40 days for the determination of RFI, receiving a complete diet in a 70:30 forage: concentrate ratio, on a dry matter basis. RFI was estimated considering the differences in observed and predicted values of dry matter intake, based on average daily gain and metabolic body weight. Sixteen animals with the highest values of RFI (high RFI) and 15 animals with the lowest values of RFI (low RFI) were selected. The experimental design was a randomized block design (2 × 3), with two groups of animals (high and low RFI) and 3 treatments with diets containing different levels of concentrate (30, 45 and 60 %). The lambs remained under this confinement regime for 60 days. The different levels of concentrate promoted differences (P < 0.05) between hemoglobin and hematocrit counts. There was an interaction between RFI and diet for hemoglobin and hematocrit counts (P < 0.05). Animals with high RFI presented larger volume of urine excreted in relation to animals with low RFI (P = 0.006), with mean values of 1.59 l/day and 1.09 L/day, respectively. Diets containing 30 % concentrate resulted in lower starch intake (P < 0.0001) and lower digestibility of starch in the total digestive tract (P < 0.0001). Animals with low RFI had lower counts of protozoa in the ruminal fluid (P = 0.04). Diets containing 60 % concentrate in their composition provided lower counts of total protozoa (P = 0.0003) in the ruminal fluid. This diet also promoted a smaller population of protozoa of the genus Dasytricha (P = 0.04) for high RFI animals. Blood parameters and utilization of starch in the total digestive tract are not affected, while ruminal fauna is affected by RFI in lambs.

Successful calcaneal common tendon tenorrhaphy in a Dorper lamb

AbstractTendon rupture is an uncommon cause of lameness in small ruminants. This report aimed to present a successful common calcaneal tendon (CCT) tenorrhaphy in a Dorper lamb after rupture during a tail docking procedure. The lamb presented a 3.5 cm linear open wound over CCT. During surgery, an incision was made over the skin on the caudolateral aspect of the distal tibia over CCT. The tendon stumps were isolated using haemostats, repair was performed via a locking‐loop suture pattern using non‐absorbable suture material. Postoperative limb immobilisation was conducted using a full‐limb compressive bandage and a modified Schroeder–Thomas splint, and follow‐up continued for 4 weeks. Ten months postsurgery, a fibrous callus was evident and the lamb exhibited no lameness. In this report, CCT tenorrhaphy using non‐absorbable suture in a locking‐loop pattern was a successful approach. Limb immobilisation in extension and specific physiotherapy are important methods to fasten the patient's rehabilitation.

Breed effects and heterosis for weight traits and tick count in a cross between an indigenous fat-tailed and a commercial sheep breed.

Ticks can compromise productivity and welfare in free-ranging sheep. Chemical tick control may not be sustainable in the long term. Alternative control measures must be sought for an integrated control programme. Birth and weaning weights as well as log transformed overall tick count of indigenous fat-tailed Namaqua Afrikaner (NA), commercial Dorper and NA x Dorper cross lambs were studied under extensive conditions. Relative to NA lambs, Dorper lambs were 22.2% heavier at weaning (P < 0.05). Geometric means for total tick count on Dorper lambs exceeded those of their Namaqua Afrikaner contemporaries by more than twofold (P < 0.05). Relative to the pure-breed midparent value, the mean performance of NA x Dorper lambs was 7.9% more for birth weight, 11.2% more for weaning weight and 26.2% less for the back transformed means for total tick count (P < 0.05). Heterosis for total tick count was slightly greater at -29.3% when data were adjusted for the larger size of NA x Dorper lambs. Crossing commercial Dorper sheep with a hardy, indigenous breed therefore resulted in lower levels of tick infestation without compromising live weight in progeny so derived. Hardy, indigenous genetic resources like the NA should be conserved and used in further studies of ovine genetics of resistance to ticks in South Africa.