The relationships between the myocardial bridge and ramus interventricularis paraconalis characteristics in lamb and sheep

The myocardial bridge (MB) is an anomaly that the myocardial fibres cover on a segment of the subepicardial coronary arteries or their branches in domestic animals and humans. The aim of the present study was to determine the relationships between the characteristics of the MB and ramus interventricularis paraconalis at three levels in lambs and adult sheep. Thirty-three hearts (16 lambs and 17 sheep) were used to determine the MB (length, angle and thickness) and vessel (vessel diameter and thicknesses of tunica intima et media of ramus interventricularis paraconalis) characteristics. Independent-samples t test was applied to compare variables between lambs and sheep. Spearman's correlation analysis was conducted to evaluate the relationships between bridge and vessel characteristics at three bridge levels. Length, angle and thickness of myocardial bridges were not significantly different between the lambs and sheep (p > .05). The mean length, angle and thickness were 24.9 ± 16.1 mm, 113.7 ± 11.2° and 1,098 ± 555 µm in 33 hearts, respectively. In lambs, the mean vessel diameters were 1,930 ± 742 µm (1,534–2,325 µm), 1,247 ± 665 µm (893–1,601 µm) and 865 ± 172 µm (774–957 µm) at the pre-bridge, bridge and post-bridge levels, respectively. In sheep, the mean vessel diameters in the same order were 1,861 ± 1,068 µm, 1,337 ± 308 µm and 1,287 ± 549 µm. The bridge prevalence was 100% in the samples examined. In conclusion, coronary arterial diseases related to myocardial bridge should not be expected in sheep for veterinary cardiology practice. It may also be concluded that the cross-breeds of the Awassi and Chios sheep may be useful in experimental studies related to myocardial bridge surgery.     

Pharmacokinetics and bioavailability of tildipirosin following intravenous and subcutaneous administration in sheep

Tildipirosin is a semi‐synthetic macrolide antibiotic commonly used in cattle and swine to treat bacterial pneumonia. The objective of this study was to investigate the pharmacokinetic profile of tildipirosin after a single intravenous (i.v.) and subcutaneous (s.c.) administration in healthy lambs. Eighteen lambs were randomly divided into three groups (n = 6 each). Lambs received a single s.c. dose of tildipirosin at 4 and 6 mg/kg b.w. in group 1 and 2, respectively. Lambs in group 3 received a single i.v. dose of tildipirosin at 4 mg/kg b.w. Blood samples were collected at 0, 0.5, 0.75, 1.5, 2, 3, 4, 6, 8, 10, 24, 36, 48 hr, and every 24 hr to day 21, and thereafter at day 28 posttildipirosin administration. The plasma concentrations of tildipirosin were determined using high‐performance liquid chromatography with tandem mass spectrometry detection (LC?MS?MS). All lambs appeared to tolerate both the intravenous and subcutaneous injection of tildipirosin. Following i.v. administration, the elimination half‐life (T_1/2), mean residence time (MRT), volume of distribution (Vd/F), and total body clearance (Cl/F) were 119.6 ± 9.0 hr, 281.9 ± 25.7 hr, 521.1 ± 107.2 L, and 2.9 ± 0.5 L/hr, respectively. No significant differences in C_max (657.0 ± 142.8 and 754.6 ± 227.1 ng/ml), T_max (1.21 ± 0.38 and 1.35 ± 0.44 hr), T_1/2 (144 ± 17.5, 156.5 ± 33.4 hr), and MRT (262.0 ± 30.2 and 250.6 ± 54.5 hr) were found in tildipirosin after s.c. dosing at 4 and 6 mg/kg b.w., respectively. The absolute bioavailability (F) of tildipirosin was 71.5% and 75.3% after s.c. administration of 4 and 6 mg/kg b.w., respectively. In conclusion, tildipirosin was rapidly absorbed and slowly eliminated after a single s.c. administration in healthy lambs. Tildipirosin could be used for the treatment and prevention of respiratory bacterial infections in sheep. However, further in vitro and in vivo studies to determine the efficacy and safety are warranted. To our knowledge, this is the first study to determine the tildipirosin pharmacokinetic parameters in sheep plasma.     

Sheep rumen metabolic development in response to age and dietary treatments

This study examined the time course of rumen metabolic development in the absence of solid feed consumption and the effect of delayed solid feed consumption on sheep rumen development. Twenty-seven lambs consumed milk replacer until slaughter at nine ages from 1 to 84 d (milk group). Three additional lambs consumed milk replacer from 1 to 48 d. From 49 d until slaughter at 84 d, these lambs were weaned onto solid feed (fed group). At slaughter, rumen contents were removed for VFA analysis and rumen epithelium was preserved for morphological examination. Rumen epithelial cells were isolated and incubated in media containing 2.5 mM U-[14C]-glucose or 10 mM 1-[14C]-butyrate. Rumen VFA concentrations did not change with age in lambs given milk replacer. At 84 d of age, intraruminal VFA concentrations were elevated in lambs consuming solid feed compared to 84-d-old lambs given milk replacer (P < .05). The number of ruminal papillae per square centimeter decreased (P < .05) while papillae length and width did not change significantly with age in rumen epithelium from lambs given milk replacer. At 84 d of age, rumen epithelium from lambs in the fed group had fewer and larger papillae/per square centimeter than rumen epithelium from lambs given milk replacer (P < .05). Rates of glucose and butyrate oxidation and acetoacetate and lactate production by rumen cells isolated from lambs given milk replacer did not change with age. Beta-hydroxybutyrate (BHBA) production was undetectable before 42 d of age in lambs given milk replacer and increased to levels found in conventionally raised adults by 84 d. At 84 d there were no differences in rates of glucose and butyrate oxidation or acetoacetate and lactate production by rumen cells between the two treatment groups. Thus, the change in substrate oxidation from glucose to butyrate, indicative of rumen metabolic maturation, does not occur in the absence of solid feed consumption. However, the development of rumen ketogenesis, as evidenced by increased BHBA production, does occur in the absence of solid feed consumption. Delaying the initiation of solid feed consumption results in rumen morphological development but does not stimulate rumen metabolic development. Increased intraruminal VFA concentrations, earlier exposure to VFA, or a longer period of exposure to VFA may be required to induce the genes responsible for rumen metabolic development.     

Productive performance and urinary excretion of mimosine metabolites by hair sheep grazing in a silvopastoral system with high densities of Leucaena leucocephala

The aim of this study was to evaluate daily weight gain (DWG), total dry matter (DM) intake, rumen degradability of forage, and urinary excretion of mimosine metabolites by hair sheep in a silvopastoral system with high densities of Leucaena leucocephala. A completely randomized design was carried out with two treatments: treatment 1 (T1) silvopastoral system with leucaena at a density of 35,000 plants/ha and treatment 2 (T2), leucaena at a density of 55,000 plants/ha. Leucaena was associated with tropical grasses Panicum maximum and Cynodon nlemfluensis. Twenty-four male Pelibuey lambs of 23.2?±?3.4?kg live weight (LW) were used (12 lambs per treatment). Results showed differences (P?<?0.05) in DWG of T1 (106.41?±?11.66?g^?1 sheep^?1) with respect to that of T2 (81.33?±?11.81?g^?1 sheep). Voluntary intake was higher in lambs from T1 (83.81?±?04.07?g DM/kg LW^0.75) with respect to that from T2 (71.67?±?8.12?g DM/kg LW^0.75). There was a difference in color of urine between sheep of T1 and T2, the latter giving positive results for the presence of metabolites derived from mimosine (3-4 dihydroxypyridine and 2-3 dihydroxy pyridone). Rumen degradability of DM of L. leucocephala was higher (P?<?0.05) compared to that of P. maximum and C. nlemfluensis (72.94?±?0.40 vs. 67.06?±?1.50 and 63.25?±?1.51?%, respectively). It is concluded that grazing at high densities of L. leucocephala affects daily weight gain of hair sheep, possibly due to ingestion of high amounts of mimosine which may exert an adverse effect on voluntary intake.     

Mitigating rumen methane and enhancing fermentation using rambutan fruit peel powder and urea in lactating dairy cows

The experiment was designed to study the use of rambutan (Nephelium lappaceum) fruit peel powder (RP) with urea (U) supplementation on rumen fermentation, digestibility, methane (CH₄) production, milk production and composition in lactating dairy cows. Four Holstein crossbred lactating dairy cows, with starting liveweight of 450 ± 15 kg with 130 ± 10 DIM (days-in-milk), were randomly allocated to respective treatments: without supplementation (control; T1), supplementation of urea (U) at 90 g/hd/day (T2), supplementation of RP at 450 g/hd/day (T3) and supplementation of RPU (RP at 450 g/hd/day and U 90 g/hd/day) (T4), respectively, using a 4 × 4 Latin square design. The results showed that the U, RP and RPU supplementation did not change feed intakes (p > 0.05) and digestibilities of DM and OM were similar. However, digestibilities of CP and NDF were increased in the U and RPU groups (p < 0.05). Acetate production was decreased, while propionate production was dramatically increased (p < 0.05) in both the RP and RPU groups respectively. Notably, the ratio of C₂:C₃, protozoal population and CH₄ production was reduced in both the RP and RPU groups. In addition, nitrogen intake and nitrogen excretion were significantly higher while nitrogen retention was increased in the U and RPU groups. Allantoin excretion and absorption, microbial protein synthesis and efficiency of microbial N supply were increased in the U and RPU supplementation groups (p < 0.05). Furthermore, milk yield, milk fat and total solids were significantly enhanced in the U and RPU groups (p < 0.05). Moreover, the 3.5% FCM was increased (p < 0.05) while milk protein, lactose, solids-not-fat and milk urea nitrogen were not altered (p > 0.05). Supplementation of either U or RPU significantly improved fibre digestibilities, rumen fermentation, microbial protein synthesis, reduced protozoal population, mitigated CH₄ production and enhanced milk yield and milk composition.     

Proteomic identification of ruminal epithelial protein expression profiles in response to starter feed supplementation in pre-weaned lambs

The present study aimed to comparatively characterize the ruminal epithelial protein expression profiles in lambs fed ewe milk or milk plus starter diet using proteome analysis. Twenty new-born lambs were randomly divided into a group receiving ewe milk (M, n = 10) and a group receiving milk plus starter diet (M + S, n = 10). From 10 d old, M group lambs remained with the ewe and suckled ewe milk without receiving the starter diet. The lambs in the M + S group were separated from the ewe and received starter feed. All lambs were slaughtered at 56 d old. Eight rumen epithelia samples (4 per group) were collected to characterize their protein expression profiles using proteomic technology. Proteome analysis showed that 31 upregulated proteins and 40 downregulated proteins were identified in the rumen epithelium of lambs in response to starter diet supplementation. The results showed that starter feeding regulates a variety of biological processes in the epithelium, especially blood vessel development and extracellular matrix protein expression. Meanwhile, the expression of proteins associated with synthesis and degradation of ketone bodies, butanoate metabolism, and citrate cycle signaling transduction pathway were upregulated in the group with starter diet supplementation, including 3-hydroxy-3-methylglutaryl coenzyme A synthase (HMGCS2, fold change [FC] = 1.93), 3-hydroxybutyrate dehydrogenase 1 (BDH1, FC = 1.91), and isocitrate dehydrogenase 1 (IDH1, FC = 8.12). The metabolic processes associated with ammonia detoxification and antioxidant stress were also affected by starter diet supplementation, with proteins, microsomal glutathione S-transferase 3 (MGST3, FC = 2.37) and IDH1, linked to the biosynthesis of glutamate and glutathione metabolism pathway being upregulated in the group with starter diet supplementation. In addition, starter feeding decreased the expression of Ras-related protein rap-1A (RAP1A, FC = 0.48) enriched in Rap1 signaling pathway, Ras signaling pathway, cyclic adenosine monophosphate (cAMP) signaling pathway, and mitogen-activated protein kinase (MAPK) signaling pathway. In summary, starter feed supplementation changed the expression of proteins related to energy production, ammonia detoxification, antioxidant stress, and signaling pathways related to proliferation and apoptosis, which facilitates the rumen epithelia development in lambs. The results provide new insights into the molecular adaptation of rumen epithelia in response to starter diet supplementation at the protein level in lambs.     

Effects of essential oils,yeast culture and malate on rumen fermentation,blood metabolites,growth performance and nutrient digestibility of Baluchi lambs fed high‐concentrate diets

The experiment was conducted to evaluate the effects of dietary supplementation with a mixture of essential oils (MEO), yeast culture (YC) and malate on performance, nutrient digestion, rumen fermentation and blood metabolites of lambs fed high‐concentrate growing diets. For this purpose, twenty Baluchi lambs (17.3 ± 0.5 kg body weight and 3 months old) were randomly assigned to four dietary treatments in a completely randomized design with five lambs per treatment. The treatment groups were as follows: (i) control: basal diet without any additive, (ii) basal diet plus 400 mg/day MEO (thymol, carvacrol, eugenol, limonene and cinnamaldehyde), (iii) basal diet with 4 g/day YC and (iv) basal diet plus 4 g/day malate. No differences between the dietary treatments were observed in dry matter intake, average daily gain or feed conversion ratio (p > 0.05). Compared with control and malate treatment, lambs fed MEO and YC had an improved crude protein digestibility (p < 0.05). Yeast culture significantly increased (p > 0.05) cell wall digestibility compared to the other treatments. No differences were observed between treatments with respect to nitrogen balance or ruminal pH and ammonia concentrations (p > 0.05). No differences were observed between treatments with respect to ruminal total volatile fatty acid concentration and molar proportions of acetate, butyrate and valerate. Molar proportion of propionate was higher (p < 0.05) for YC and malate compared to control and MEO. Plasma glucose concentration was higher (p < 0.05) in lambs fed YC and malate than in lambs fed the control or the MEO diet. Blood concentration of triglycerides significantly decreased when feeding the MEO and YC diets (p < 0.05). It was concluded that YC may be more useful as a feed additive for manipulation of rumen fermentation in lambs fed with high‐concentrate diets than MEO and malate, because YC enhanced crude protein and cell wall digestibility, ruminal molar proportion of propionate and plasma glucose concentration.     

A Field Study of Serum,Colostrum, Milk Iodine,and Thyroid Hormone Concentrations in Postpartum Draft Mares and Foals

Iodine, thyroxine (T4) and triiodothyronine (T3) are required for normal fetal growth, maturation, and neonatal survival. There is a lack of robust information on iodine levels found in colostrum, milk, and serum of mares and foals after a healthy pregnancy. Our objective was to characterize colostrum, milk, and serum iodine levels in healthy postpartum mares and foals (n = 10) and explore relationships with thyroid hormone concentrations. Colostrum, milk, and jugular blood samples from draft breed mares and foals with an estimated average iodine daily intake of 39 mg per mare during pregnancy were obtained at Day 0 (foaling date) and/or 10 days later. Parameters studied were (1) mare basal concentrations of serum: TT3, TT4, and iodine; (2) iodine in colostrum at Day 0 and milk iodine (Day 10); and (3) foal basal: TT3, TT4, and serum iodine (Days 0 and 10). Median ± median error colostrum iodine levels (165 ± 15.1 μg/L) were higher than milk (48 ± 5.6 μg/L; P = .007) levels. Median ± median error foal serum iodine (268.5 ± 7.6 μg/L), TT4 (1,225 ± 47.8 nmol/L), and TT3 (14.2 ± 1.1 nmol/L) at foaling date were higher than at 10 days (serum iodine: 70 ± 3.6 μg/L; TT4: 69.6. ± 20.4 nmol/L; and TT3: 5.4 ± 0.3 nmol/L). In conclusion, equine mammary tissue concentrates iodine beyond plasma levels, making colostrum and milk a significant source of iodine. Foal serum iodine levels are high in the neonatal period and are positively correlated with TT4, which is important for neonatal adaptation.     

湖羊羔羊早期断奶前后瘤胃发酵与微生物区系的变化

本试验旨在研究湖羊羔羊早期断奶前后的瘤胃发酵与微生物区系变化，为幼龄反刍动物瘤胃发育变化理论以及羔羊的早期培育等提供依据。选择初生重接近的湖羊公羔（3.81 kg±0.55 kg）16只，1~7日龄饲喂母乳，8日龄与母羊分离，开始饲喂代乳粉（按8日龄体重的2%，分3次等量饲喂）和开食料（自由采食），35日龄断奶。分别于断奶前（21日龄）、后（42日龄）各选择5只羔羊进行屠宰，采集瘤胃内容物，测定瘤胃发酵、酶活和微生物区系。结果表明，断奶后羔羊的瘤胃总挥发性脂肪酸、乙酸、丙酸、丁酸及纤维素酶和α-淀粉酶活性均极显著高于断奶前（P<0.01）。断奶后瘤胃菌群多样性和丰富度均低于断奶前（P<0.05）。断奶前后的优势菌门均为拟杆菌门（Bacteroidetes）和厚壁菌门（Firmicutes），其中，拟杆菌门为第一优势菌门，在断奶前后分别占61.96%和65.36%，厚壁菌门为第二优势菌门，在断奶前后分别占32.08%和24.03%；两菌门之和在断奶前后分别占瘤胃总菌门的94.04%和89.39%。断奶前后的优势菌属均为unidentified_Prevotellaceae，分别占21.85%和38.49%。断奶前后羔羊瘤胃微生物的功能没有显著变化，都主要集中在复制和修复、碳水化合物代谢和翻译等途径。以上结果说明，羔羊早期断奶后的瘤胃发酵和酶活增强，菌群多样性和丰富度有所降低，在早期断奶前后的优势菌群和功能相似。     

Effect of tropical browse leaves supplementation on rumen enzymes of sheep and goats fed <Emphasis Type="Italic">Dichanthium annulatum</Emphasis> grass-based diets

In a switch-over experiment, eight male animals, four each of sheep and goats of local breeds with mean body weight of 26. 8 ± 2.0 and 30.0 ± 2.1 kg, were fed Dichanthium annulatum (DA) grass and four browse species viz. Helictris isora, Securengia virosa, Leucaena leucocephala (LL) and Hardwickia binnata (HB) in four feeding trials to assess their supplementary effect on activity of rumen enzymes. The sheep and goats were offered DA grass with individual browse in 75:25 and 50:50 proportions, respectively, for more than 3 months during each feeding trial, and rumen liquor samples were collected twice at 0 and 4 h post feeding after 60 and 90 days of feeding. Glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT) and glutamate dehydrogenase (GDH) enzymes were determined in the bacteria and protozoa fractions of rumen liquor, while cellulase enzyme activity was measured in mixed rumen liquor. LL and HB had the highest and lowest contents of CP, while fibre contents were lower in early than later browse leaves. Supplementation of browse leaves significantly (P < 0.05) affect the specific activity of GDH enzyme in bacteria fraction of rumen liquor of animal species, while GDH activity was similar in protozoa fraction of rumen liquor of sheep and goats on all DA grass–browse-supplemented diets except DA–HB (42.8 units/mg protein), where activity was significantly (P < 0.05) low. Specific activities of GOT and GPT enzymes in both bacteria and protozoa fractions of rumen liquor differ significantly (P < 0.05) due to supplementation of browse leaves to DA grass. Browse leaves significantly (P < 0.05) affect the cellulase enzyme activity in animal rumen liquor, being highest on DA–LL (193.4) and lowest on DA–HB diet (144.8 μg sugar/mg protein). Goat exhibited higher activities of GOT and GPT than sheep in both bacteria and protozoa fraction of rumen liquor, while cellulase activity was similar between the animal species on the grass–browse leaves diets. Results indicate that browse leaves supplementation affect the enzyme activities of sheep and goats rumen, while the goats rumen liquor had higher activities of GOT, GPT and GDH enzyme than sheep.     

Effect of forage inclusion and particle size in diets of neonatal lambs on performance and rumen development

A slaughter experiment was conducted to determine the effects of alfalfa particle size on rumen morphology and performance of lambs. Twenty‐four Balouchi lambs aged 21 days (9.1 ± 1.1 kg) were randomly fed control (diet without alfalfa hay; CON) and mixed rations containing 15% finely ground (FINE; 2 mm) and 15% coarsely chopped alfalfa hay (LONG; 3 to 4 cm). After a 63 days feeding period, nine animals (three per treatment) were slaughtered to obtain ruminal tissue samples for morphological analyses. Alfalfa particle size did not affect (p > 0.05) papillae density, height, width, epithelium depth and surface area. Coarse alfalfa decreased the stratum corneum and increased (p < 0.05) muscle depth compared with fine and control diets. Neither DNA content and nor RNA concentration of rumen tissue was affected by feeding different diets. Forage particle size did not affect the blood concentration of glucose, urea nitrogen (BUN), beta‐hydroxybutyric acid (BHBA) and non‐esterified fatty acids (NEFA). Dry matter intake and feed conversion ratio were higher for control diet; however, there were no significant differences between treatments for average daily gain. These data suggest that coarse alfalfa significantly reduces the stratum corneum and increases muscularity of rumen wall and tended to better feed conversion ratio.     

Effects of pistachio by‐products in replacement of alfalfa hay on populations of rumen bacteria involved in biohydrogenation and fermentative parameters in the rumen of sheep

The objective of this study was to investigate the effect of sundried pistachio by‐products (PBP) as a replacement of alfalfa hay (AH) on blood metabolites, rumen fermentation and populations of rumen bacteria involved in biohydrogenation (BH) in Baluchi sheep. Four adult male Baluchi sheep (41 ± 1.3 kg, BW) fitted with ruminal cannulae were randomly assigned to four experimental diets in a 4 × 4 Latin square design. The dietary treatments were as follows: (i) control, (ii) 12% PBP (0.33 of AH in basal diet replaced by PBP), (iii) 24% PBP (0.66 of AH in basal diet replaced by PBP) and (iv) 36% PBP (all of AH in basal diet replaced by PBP). The basal diet was 360 g/kg dry matter (DM) alfalfa hay, 160 g/kg DM wheat straw and 480 g/kg DM concentrate. The trial consisted of four periods, each composed of 16 days adaptation and 4 days data collection including measurement of blood metabolites, rumen fermentation and population of bacteria. No differences were observed in rumen pH among the treatments, while rumen ammonia‐N concentrations were decreased (p< 0.05) with increasing PBP by up to 36% DM of the diets. Using of 36% PBP in the diet reduced (p < 0.05) total volatile fatty acids (VFA) concentrations and the molar proportion of acetate, while the concentration of propionate, butyrate and acetate to propionate ratio were similar to all other treatments. The concentration of blood urea nitrogen (BUN) decreased (p < 0.01) with increasing PBP by up to 36% DM in the diets of sheep. However, other blood metabolites were not affected by the experimental diets. It was concluded that PBP in replacement of AH had no effects on the relative abundance of Butyrivibrio fibrisolvens and Butyrivibrio proteoclasticus in relation to the control diet.     

Paraoxonase 1 (PON1) activity in serum,follicular fluid and seminal plasma of sheep

This work aimed to describe the activity of paraoxonase 1 (PON1) in serum, follicular fluid and seminal plasma of sheep. Average serum PON1 activity was 286.8 ± 96.2 U/ml in females and 237.6 ± 18.9 U/ml in males. There was a positive correlation between PON1 activity in serum and follicular fluid in females, being twice higher in serum than in follicular fluid (148.8 ± 15.7 U/ml). PON1 activity in males’ serum was 10‐fold higher than in seminal plasma (21.18 ± 14.2 U/ml), and there was no correlation between PON1 activity in both compartments. Finally, this work suggests that PON1 activity of in sheep is higher compared to other mammalian species, and there is an association between PON1 in serum and follicular fluid only.     

瘤胃保护型亮氨酸对滩羊母羊繁殖性能、消化性能及初乳品质的影响

本试验旨在探讨瘤胃保护型亮氨酸(RP-Leu)对滩羊母羊繁殖性能、消化性能及初乳品质的影响。选取体重为(42.18±2.62)kg的经产滩羊母羊48只,随机分为4组,每组3个重复,每个重复4只。对照组饲喂基础饲粮,试验组在对照组基础上分别添加0.10%、0.20%和0.30%的RP-Leu。试验期为妊娠后第35天始至分娩后第60天(断奶)结束。结果表明:与对照组相比,妊娠期母羊饲粮添加0.20%RP-Leu显著提高了羔羊初生重和断奶重(P0.05),显著提高了妊娠期母羊粗蛋白质的表观消化率(P0.05),显著提高了初乳中乳脂、乳蛋白和乳糖含量(P0.05),同时显著降低了母羊分娩后第15天血清尿素氮含量(P0.05)。综上所述,饲粮中添加0.20%RP-Leu能够改善妊娠滩羊氮沉积和初乳品质,同时实现促进羔羊生长发育的目的。     

Epidemiology of nematode parasites of sheep around Jimma,southwestern Ethiopia

An investigation was made into the epidemiology of nematode infections of sheep in two districts of Jimma zone, southwestern Ethiopia. We used two approaches—long-term monitoring of identified sheep for nematode infection and abattoir or market survey for analysis. In the first monitoring regime, we used 80 lambs [40 sheep (20 per sex) from each district (Dedo and Yebu)] averaging 4–5 months of age. Faecal egg counts (FEC), packed cell volume (PCV) and body weight changes were monitored over a period of 1 year. Additionally, faecal samples were collected (on a weekly basis) from sheep brought to abattoir/market for 1 year to monitor faecal egg counts. The nematode parasite burden, as judged by FEC and PCV, was generally low indicating that the climatic conditions are not conducive to the development and survival of nematode eggs and the free-living stages; hence, little transmission occurred. In the experimental flocks, the highest FEC and lower PCV were recorded during the long rainy season (June to September) with peak in August and September. Faecal samples collected from abattoir/market also followed the same trend. Results from experimental sheep indicated that location had a significant (P < 0.01) effect on FEC, PCV and average daily body weight gain. The FEC and PCV for sheep in Yebu (mid-altitude) district were 126 ± 3.33 and 30.6 ± 0.26, whereas the values for Dedo (highland) were 93 ± 4.35 and 32.0 ± 0.21, respectively. The results indicate that the highland areas are comparatively less favourable to the survival and development of nematodes. Female lambs had lower FEC and higher PCV compared to male lambs (P < 0.05). The overall nematode parasite challenge in the area, however, is low. We, therefore, recommend rotational grazing management combined with monitoring parasite load and selective treatment to reduce productivity loses and pasture contamination.     

青海海西荒漠半荒漠草地氮硫的季节变化及盈缺分析

在春季(3月中旬),夏季(7月中旬)和秋季(11月中旬)对青海海西地区荒漠半荒漠草地中的土壤、可食牧草和绵羊的血清、瘤胃液、被毛等进行了检测分析。结果表明:7月份的土壤全氮为(0.33±0.10)%,土壤有效硫为(42.65±8.57)mg/kg,均分别显著高于3月份土壤全氮(0.15±0.04)%、土壤有效硫(20.00±3.02)mg/kg和11月份土壤全氮(0.07±0.03)%、土壤有效硫(37.85±7.91)mg/kg。三季都能满足植物生长的基本需要;可食牧草中的全氮和全硫在7月份时最高,春季和秋季,牧草含量远不能满足绵羊生长的需要;血清中的氮、硫在3月份、7月份和11月份表现出相同的变化趋势,均为7月份>11月份>3月份。3月份血清白蛋白的含量(33.92±9.77)g/L显著低于7月份(53.11±10.59)g/L和11月份(53.53±7.74)g/L,三季含量均低于绵羊血清白蛋白正常含量;瘤胃液氮与牧草氮含量和血清白蛋白的变化规律一致。     

Energy requirements of early‐weaned Dorper cross‐bred female lambs

The net and metabolizable energy (NE and ME) requirements of Dorper cross‐bred female lambs with BWs of 20–35 kg were assessed in a comparative slaughter trial. Thirty‐five Dorper × thin‐tailed Han cross‐bred female lambs weaned at ~50 days of age (20.3 ± 2.15 kg BW) were used. Seven randomly selected lambs were slaughtered at the start of the trial (baseline group). An intermediate group consisting of seven randomly selected lambs fed ad libitum was slaughtered when the lambs reached an average BW of 28.5 kg. The remaining 21 lambs were allotted randomly to three levels of dry matter intake: ad libitum or restricted to 70% or 40% of the ad libitum intake. All the lambs were slaughtered when the sheep fed ad libitum reached a BW of 35 kg. Total body energy, nitrogen, fat, ash and moisture content were determined. In a digestibility trial, an additional 15 Dorper × thin‐tailed Han cross‐bred female lambs (28.7 ± 1.75 kg BW) were housed in metabolism cages and used in a completely randomized design experiment to evaluate the ME value of the diet at the three feed intake levels. The maintenance requirements for NE and ME were 245.5 and 380.3 kJ/kg metabolic shrunk body weight (SBW^0.75) respectively. The partial efficiency of energy use for maintenance was 0.645. The NE requirements for growth ranged from 1.18 to 5.18 MJ/d for the lambs gaining 100–350 g/d from 20 to 35 kg BW. Partial efficiency of ME for growth was 0.44. In conclusion, the current study suggests that the NE requirement for maintenance and growth of Dorper early‐weaned cross‐bred female lambs is lower than the current AFRC and NRC recommendations.     

草地藏系绵羊乳的组成及乳蛋白多态性

测定了63只草地藏系绵羊乳常规营养成分的含量,并用聚丙烯酰胺凝胶电泳分析了乳蛋白组分及乳蛋白多态性。结果表明:草地藏系绵羊脱脂乳中蛋白含量为(48.45±1.66)g/L,乳糖含量为(41.93±0.64)g/L,乳脂肪含量为(69.43±1.44)g/L;脱脂乳蛋白主要包括α-乳清蛋白、β-乳球蛋白、酪蛋白、免疫球蛋白等组分,酪蛋白的相对含量约为52%。乳中酪蛋白、β-乳球蛋白均未检测到多态性。试验检测到4种分子量类型的乳上皮粘蛋白(MUC1),分子量分别为214、209、207和205 ku。试验结果提示,草地藏系绵羊乳蛋白多态性较为贫乏。     

Factors affecting the milk yield and composition over lactation of prolific D’man ewes in Tunisian oases

This work aimed to investigate milk potentiality and the influence of some non-genetic factors both on milk yield production and composition in prolific D’man sheep. Observations were performed in eighty lactating D’man ewes maintained under an intensive oases system in Southern Tunisia. Daily milk yield was determined at 7-day intervals using oxytocin?+?hand milking method. Chemical milk composition was determined by Lactoscan. Total productions over lactation (milk, fat, and protein) were estimated using the Fleischmann method. Daily milk yield averaged 1.64?±?0.02 l. It increased to a plateau from the third to the fourth week of lactation, and decreased gradually to the tenth week. D’man ewes produced 128.91?±?3.14 l of milk, 9.23?±?0.26 kg of fat, and 5.26?±?0.12 kg of total proteins. Overall, milk contained 16.17% of total solids, 7.08% of fat, 4.04% of proteins, 4.32% of lactose, 9.09% of solids-not-fat, and 0.73% of ash. Lambing season affected the daily milk yield and milk composition, where fat and total proteins were highest in autumn. Total solids, lactose, solids-not-fat, and ash were higher in winter than in autumn and summer. Ewes reared multiple lambs produced more milk than those reared singles. Dams nursing triplets or more had the highest milk total proteins, and the lowest total solids and fat levels. Adult ewes produced more milk compared to younger and older ewes, and their milk contained higher total solids, fat, and ash levels than milk from young ewes. Ewes with asymmetric udder produced less and more concentrated milk than ewes with symmetrical udder. Daily milk yield was negatively correlated to total solids, fat, and total proteins amounts. In contrast, litter survival at weaning was positively correlated to the amounts of total milk, fat, and total proteins.