Blood selenium concentrations of sheep and goats from selected areas of Kenya

A systematic mapping technique based on blood, forage and soil selenium levels was employed to locate areas of selenium deficiency, adequacy or excess in areas of Kenya where grazing of small ruminants predominates. A total of 1,478 blood samples from both sheep and goats, 180 forage samples and 90 soil samples were analysed for selenium levels. During the wet seasons 28% of the sheep and 15% of the goats had marginal to deficient blood selenium concentrations while during the dry season 20% of the sheep and 12% of the goats had marginal to deficient blood selenium concentrations. Forage samples had a range of 0.03 to 0.66 ppm selenium while soil samples had a range of 0.06 to 0.98 ppm selenium. Although many animals had blood selenium levels of less than 0.05 ppm, below which selenium deficiency signs might occur, none of the animals manifested these signs.     

西藏那曲地区放牧草地营养和产量的季节性变化与西藏绒山羊采食喜好研究

本研究以西藏那曲地区的尼玛县天然放牧草地为对象,测定其牧草营养季节性变化、西藏绒山羊的采食喜好以及根据植被指数估算草地产量和载畜量。结果表明,牧草中的营养物质含量在季节间差异显著,粗蛋白含量（CP）和干物质（DM）重量随着季节的增长呈现着倒"V"字型的变化趋势,中性洗涤纤维（NDF）以及酸性洗涤纤维（ADF）含量变化趋势相反。西藏绒山羊对紫花针茅（Stipa purpurea）、二裂委陵菜（Potentilla bifurca）、木根香青（Anaphalis xylorrhiza）、聚头蓟（Cirsium souliei）和弱小火绒草（Leontopodium pusillum）等牧草在夏季的喜食程度与秋季相比有显著变化（P<0.05）。对喜食及嗜食的牧草种类与牧草的盖度总和显著相关（P<0.05）。高寒草甸草地的TM遥感影像提取的NDVI与草地鲜草量和生物量分别呈线性关系和对数关系,相关系数分别为0.8108和0.7970。研究结果还表明那曲地区全年都存在超载放牧现象。     

Is Leucaena leaf useful as a selenium supplement for growing Philippine goats?

The effects of Leucaena leucocephala leaf (LL) supplementation on selenium (Se) status of growing Philippine goats were determined in the present study. A total of 12 3–4 month old male goats with mean bodyweight of 8.8 kg was used. All animals received a basal diet comprised of different forages. Six of the animals were supplemented with LL (22.9% CP) while the remaining six animals were not supplemented (control). The rate of LL to the total forage diet offered to the LL‐supplemented animals was 25%. Bodyweight measurement, blood and forage sampling were carried out every 2 weeks during the 4 months of experiment. Selenium, sulfur, calcium, phosphorus, magnesium, copper and zinc concentrations were analyzed after wet digestion. Leucaena leaf seemed to have higher Se and calcium, but lower copper and zinc concentrations than was observed in grasses fed to the animals. Bodyweight of growing goats in LL‐supplemented group tended to be higher than that of control animals. Supplementation of LL resulted in high whole blood Se concentration of growing goats. In the last month of this experiment, whole blood in all supplemented animals contained higher Se concentration than the deficient level of 20 ng/mL, while Se concentration in the control group was slightly above the deficient level.     

Has bovine somatotropin (BST) an effect upon drug disposition? Comparative studies in goats and cattle with sulphadimidine and antipyrine after parenteral administration of BST,zeranol and proligestone

Daily subcutaneous BST injection in lactating cows, bulls and castrated male dwarf goats did not induce significant changes in the pharmacokinetic parameters of antipyrine (AP) and sulphadimidine (SDD). Similarly, no changes were obtained after injection of slow-release BST formulations in lactating cows and non-lactating female goats. In contrast to androgenic hormones, both zeranol and proligestone had no effect upon the disposition of AP and SDD, although both synthetic hormones did induce enhanced plasma somatotropin concentrations. In goats, metabolic effects induced by zeranol and BST included significant reductions in plasma urea values, whereas plasma creatinine levels were somewhat lower after daily BST administration.     

季节对内蒙古白绒山羊采食牧草及粪便特性的影响

试验分别在春、夏、秋、冬季对内蒙古3种类型白绒山羊成年母羊群所采食主要牧草进行了营养成分分析,并采集粪便以测定其粪便特性,旨在研究季节因素对内蒙古白绒山羊采食牧草及粪便特性的影响,从而为内蒙古白绒山羊粪便的利用提供理论依据。结果表明,内蒙古鄂尔多斯市、阿拉善盟、巴彦淖尔市的牧草DM含量在春季、夏季、秋季、冬季分别为39．60％。53．21％、40.39％～48．81％、64．55％～94．50％、92．00％～95．00％;牧草NDF含量表现为秋、冬季较高,春、夏季较低;牧草CP含量,冬季最低（4．68％～6．17％）,春季最高（14．65％～17．44％）。春夏秋冬四季粪便磷浓度平均为1．10％、0．75％、0．71％、0．59％,3种类型内蒙古白绒山羊粪便磷含量季节间差异显著（P〈0．05）,春夏两季大于秋冬两季;粪便氮浓度在春夏秋冬四季平均为1．99％、1．7l％、1．61％、1．44％,季节因素对粪便氮含量影响差异显著（P〈0．05）,且春季最高,然后呈现逐渐降低的趋势;季节对内蒙古白绒山羊粪便干物质影响较大,阿尔巴斯型白绒山羊季节间表现为差异显著（P〈0．05）,二狼山型白绒山羊季节间表现为差异极显著（P〈0．01）,阿拉善型白绒山羊季节间表现为差异不显著（P〉0．05）,粪便中干物质平均含量春夏秋冬四季依次为72．56％、79．60％、65．52％、95．87％,其中。冬季最高、秋季最低。     

Alpha-tocopherol, selenium and polyunsaturated fatty acid concentrations in the serum and feed of spring-calving dairy heifers

The objectives of this study were to provide baseline data for alpha-tocopherol, selenium and polyunsaturated fatty acid concentrations in the serum and feed of New Zealand dairy cattle, and to assess the likelihood that abnormal peroxide metabolism has a role in the impaired lactational and reproductive performance noted in selenium-deficient cattle. Twenty-four Friesian heifers were randomly allocated one of four winter diets consisting of hay with or without selenium supplementation, or pasture and silage with or without selenium supplementation. A winter diet consisting exclusively of hay (alpha-tocopherol concentration 19 mg/kg of dry matter) resulted in a pre-calving serum alpha-tocopherol concentration of 1.2 mg/l compared to 4.5 mg/l for pastured heifers (p<0.01). The pre-calving alpha-tocopherol concentration for the heifers fed hay fell into the range considered deficient (<2.0 mg/l), whereas heifers fed pasture and silage remained in the range considered adequate throughout the study period. Serum fatty acid concentration, and the proportion of fatty acids that were polyunsaturated, were lowest in the hay-fed heifers before calving (1.0 mg/ml, 37.1% respectively), and remained unchanged following re-introduction to pasture after calving in late July and August. Serum fatty acid concentration did not increase following the re-introduction of the heifers to pasture because of the unexpectedly low fatty acid concentration (4.8 g/kg of dry matter) of the mature winter pasture. In October, however, the proportion of fatty acids in serum that were polyunsaturated increased (50%) as did serum cy-tocopherol concentrations (greater than 13 mg/l). Mean serum selenium concentrations in the unsupplemented heifers ranged from 139 to 204 nmol/l, being lowest in October (p<0.01). Supplementation with intraruminal selenium pellets (two pellets delivering about 3 mg of selenium/day) increased serum selenium concentration and glutathione peroxidase activity (p<0.01) whereas the type of winter diet had no effect (p>0.05). These results suggest that dairy cattle wintered on hay can become Vitamin E-depleted, whereas the feeding of pasture and silage should provide adequate Vitamin E. The pasture offered following calving during July and August provided a low dietary polyunsaturated fatty acid challenge, suggesting that abnormal peroxide metabolism is unlikely to be an important mechanism in the impaired performance of selenium-deficient adult cattle which calve at this the of year.     

天山北坡季节牧场牧草营养动态研究

对天山北坡四季牧场牧草营养动态测定分析,结合放牧绵羊体重变化态势,揭示“夏壮、秋肥、冬瘦、春乏”这一传统草原畜牧业的规律,转变经营方式,揭高冷季饲养水平是实现草原畜牧业可持续发展的正确途径。     

Seasonal diet composition and forage selectivity of Boer goats in a semi-arid gypsophilous grassland

Botanical and chemical compositions of Boer goat diets, determined with repeated collection of forage samples taken from the goat’s mouth, were studied in a gypsophilous grassland during four seasons of the year. Ten pluriparous goats were used to collect selected forage species. Shrubs were a minor dietary component throughout the year (<7.5%). Goats selected more (p?<?0.01) grass during autumn and winter (34.2–37.8%) than during spring (21.2%) and summer (29.0%). During all seasons goat diets were dominated by forbs (>59%). Diets were lowest (p?<?0.05) in percentage of crude protein during spring, summer and autumn (13.2?±?3.5, 13.2?±?2.4 and 14.2?±?3.9, respectively) than winter (17.5?±?2.9) with levels above the recommended quantities for goats throughout the year. In vitro dry matter digestibility of forages selected by goats did not differ between seasons (range 47.4–53.3%). It was concluded that in this particular ecosystem goats preferred forb species over grasses across all seasons. In addition, goats maintained relatively stable diet quality by forage-class mixing of diets.     

Selenium in New Zealand pastures

In grasses and clovers the highest concentrations of selenium were found in the leaves. The selenium content of different species in spring pastures on the same soil type did not vary widely although the slower growing and more deeply rooting species contained higher levels. The concentration of selenium in a pasture varied with time of the year, the lower levels being usually associated with conditions that stimulated rapid growth of the herbage, although factors other than growth rate were also involved. Lucerne appeared to be unusual in that in some areas it accumulated much higher levels of selenium than was found in other associated species. A very wide variation in levels of selenium in pastures growing on different soils has been observed 3-1500 ng/g). Selenium-responsive unthriftiness in grazing lambs occurred where the selenium content of spring pastures was <20 ng/g. Pastures containing >30 ng/g were apparently adequate while intermediate levels were probably marginally deficient.     

Effects of supplemental feed with or without ionophores on lambs and Angora kid goats on rangeland

Effects of supplemental feed and of ionophore concentration in supplemental feed on gastrointestinal rate parameters, forage intake and weight gain were measured in individually supplemented grazing lambs and Angora kid goats. The 12 dietary treatments included negative control (NC; grazed forage only), positive control (PC; grazing plus 13.6 g supplement DM/kg.75), and PC plus monensin or lasalocid, each at 33, 66, 99, 132 or 165 mg/kg in the supplement. Gastrointestinal fill, retention time, turnover rate and fecal output were estimated by applying a single-compartment model to the fecal excretion of a single dose of ytterbium. Forage digestibility was estimated from forage and fecal concentrations of indigestible fiber. Supplemental feed increased digestibility of forage and total intake in sheep but had no effect on forage intake. In goats, supplemental feed did not increase digestibility of forage but decreased forage intake. Supplemental feed increased weight gain in both species. Increasing the monensin concentration in supplemental feed reduced supplement intake greatly in sheep and slightly in goats. Lasalocid did not affect intake of supplement by either sheep or goats. Overall, ionophores had minimal effects on the response criteria. Because feed intake and digestibility were not affected, any increase in gain or efficiency in lambs or kid goats on rangeland from consumption of ionophores must be a result of their therapeutic value or of improved physiological efficiency.     

The effect of Ruapehu ash on the trace element status of grazing ruminants in the Taihape district

AIMS: To investigate the impact of a large (2-5 mm) volcanic ash deposition containing sulphur and selenium on the trace element status of livestock grazing affected farmland. METHODS: The trace element status of lambs, cows and hinds were compared on affected properties from slaughterhouse liver samples taken prior to and following the eruption at corresponding times of the year. Liver concentrations of selenium, copper and Vitamin B12 were compared. RESULTS: There was a statistically significant elevation of liver selenium concentration in all classes of stock sampled. Contrary to expectations, liver copper concentrations did not fall in any class of stock sampled and in fact with hinds there was a statistically significant elevation. The Vitamin B12 status of lambs showed a significant reduction, which could not be attributed to any specific aspect of the composition of the ash. CONCLUSIONS: A large deposition of selenium in volcanic ash which increased pasture levels by a factor of about 10 times also increased the liver selenium concentration of livestock. A large deposition of sulphur in volcanic ash which increased soil sulphur levels by a factor of about 30 times on a yellow brown loam soil did not result in a depletion of the liver copper concentrations of livestock grazing the affected farmland. CLINICAL RELEVANCE: Ruapehu ash deposits increased the liver selenium concentrations of livestock but did not result in toxic levels. Large ash deposits of sulphur to the yellow brown loam soil increased soil sulphur concentrations to many times that which could be achieved economically with fertiliser but did not result in liver copper depletion of livestock.     

Effects of concentrate supplementation on blood mineral concentration of growing upgraded Philippine goats

A total of 32 4‐month‐old‐upgraded Philippine goats with mean bodyweight of 13.5 kg were used to study the effects of concentrate supplementation on mineral status of growing goats. All animals received a basal diet comprised of different forage species. Twenty of the animals were supplemented with concentrate at a rate of 150–200 g dry matter/day while the remaining 12 animals were not supplemented. Blood sampling and bodyweight measurement were done every 2 weeks during the 5 months of experiment. Forage, concentrate and blood sulfur, calcium, phosphorus, magnesium, copper, zinc and selenium concentration were analyzed after wet digestion. Forage mineral contents, except for zinc and selenium, were sufficient for requirements of ruminants. Concentrate mineral contents were much higher than the requirements, but did not exceed the toxic levels. The concentrate supplementation resulted in high (P < 0.05) plasma phosphorus, copper, zinc, whole blood selenium concentrations and bodyweight of growing goats, although some supplemented animals showed plasma zinc concentration below the lower critical level. It was recommended that pellets, glass bolus or capsules that contain deficient minerals, such as zinc and selenium, should be used in the study area.     

Selenium in New Zealand pastures

In grasses and clovers the highest concentrations of selenium were found in the leaves. The selenium content of different species in spring pastures on the same soil type did not vary widely although the slower growing and more deeply rooting species contained higher levels. The concentration of selenium in a pasture varied with time of the year, the lower levels being usually associated with conditions that stimulated rapid growth of the herbage, although factors other than growth rate were also involved. Lucerne appeared to be unusual in that in some areas it accumulated much higher levels of selenium than was found in other associated species. A very wide variation in levels of selenium in pastures growing on different soils has been observed (3-1500 ng/g).

Selenium-responsive unthriftiness in grazing lambs occurred where the selenium content of spring pastures was <20 ng/g. Pastures containing >30 ng/g were apparently adequate while intermediate levels were probably marginally deficient.     

Concentration of ammonia in the urine of dairy cows given green feed rations and winter feed rations

The concentration of ammonia in urine at a known level of energy yielding nutrients offered in feed rations was determined in 987 dairy cows in four summer feeding seasons and 1420 cows in three winter feeding seasons. The long-term average ammonia levels in urine showed no significant variation with the two types of feed rations. Different feed rations in the feeding seasons had no significant influence on ammonia concentration in the urine of lactating cows. On a long term-average as well as in the overwhelming majority of the winter and summer feeding seasons, high-pregnant cows had significantly higher ammonia contents in urine than the cows in the first and second lactation stage. At feeding rations complying with Czechoslovak Standard CSN 46 7070 the content of ammonia in the urine of lactating cows was lower than the recorded long-time averages and averages for individual stages; on the other hand, in high-pregnant cows the ammonia level was higher in both types of feed rations and the difference from lactating cows increased 3.25 times. This suggests that neither do the feed rations currently used in practice nor those strictly adhering to the Czechoslovak Standard meet the biological demand of high-pregnant cows and often lead to the injury of hepatal parenchyma. Ammonia concentration of 11.7 to 58.7 mmol per litre of urine is considered as a tolerable limit.     

甘南玛曲不同年龄欧拉型藏羊放牧采食量季节动态研究

为确立高寒地区天然草地欧拉型藏羊放牧采食量的季节动态变化,本试验采用TiO₂外源指示剂法和瘤胃尼龙袋法分别测定欧拉型藏羊不同季节排粪量和牧草消化率从而计算放牧采食量。结果表明:玛曲高寒草地牧草干物质消化率(DMD)和粗蛋白(CP)含量夏季显著(P < 0.05)高于冬春季与秋季;欧拉型藏羊各年龄段排粪量3季差异显著(P < 0.05)且秋季 > 夏季 > 冬春季;随着年龄增长,欧拉型藏羊三季牧草采食量均有增大的趋势,同年龄段不同季节的藏羊采食量和代谢采食量(除4岁母羊)差异显著(P < 0.05)且秋季 > 夏季 > 冬春季;各年龄段藏羊累计牧草消耗量(AFC)差异显著(P < 0.05)分别为339.37,757.58,1185.93和1655.61 kg。由此可见,牧草干机物质消化率、排粪量和采食量夏秋季较高、冬春季较低,随着年龄增大排粪量和采食量有增高的趋势。因此,在高寒牧区应提倡草地季节性畜牧业,充分考虑牧草营养与动物营养需求之间的耦合性来提高经济和生态效益。     

The Status of Selected Minerals in Soil,Forage and Beef Cattle Tissues in a Semi-arid Region of Zimbabwe

Five districts in the Matabeleland region, an arid western area of Zimbabwe, were investigated for the status of Ca, P, Na, Cu and Zn in soil, forage and cattle during the wet and dry seasons over a period of one year. The cattle came from the natural grazing lands and were not supplemented at the time of sampling. Some deficiencies in soil Zn and P were found in the districts of Lupane and Bulilima-mangwe, respectively. Dry season soil Ca, Cu and P concentrations were significantly higher (p < 0.05) than rainy season values owing to leaching in all five districts. Most forage samples had mineral concentrations below the critical levels known to be adequate for animal requirements. Forage levels of Ca, Na, Cu and Zn significantly increased (p < 0.05) with advancing maturity, while P significantly decreased (p < 0.05) in almost all the districts. Marked deficiencies of minerals were found in cattle tissues and these levels followed the seasonal trend seen in the forage. These results indicate that cattle in Matebeleland are deficient in P, Ca, Cu and Zn and that grazing areas in the region cannot provide adequate levels of the five minerals studied.     

Effects of the natural sweetener rebaudioside A on intake,nutrient digestion,rumen fermentation,and blood biochemical parameters in adult goats during summer

The effects of dietary rebaudioside A inclusion on feed intake, digestion of nutrients, rumen fermentation, and blood biochemical parameters of goats were evaluated in a replicated 3 × 3 Latin square study. Nine adult goats during summer were fed a basal forage/concentrate-based diet and the forage was chopped rice straw. The three dietary treatments were 0, 350, and 700 mg rebaudioside A per kg chopped rice straw on a DM basis. No significant improvement was observed in dry matter intake (DMI) of forage and diet among treatments. Nutrient digestibility of DM and organic matter (OM) showed a significant trend (p < .10) across groups. Rebaudioside A inclusion significantly (p < .01) increased the concentration of total volatile fatty acids in the rumen, however, there were no differences in concentration of ruminal ammonia, and molar proportions of acetate, propionate, and butyrate. About blood metabolites, increasing rebaudioside A in the diet caused a quadratic response in glucose and total protein, and albumin concentrations. Under the conditions of this study, supplementation with rebaudioside A at 350 and 700 mg/kg forage did not improve consumption of rice straw-based diet in adult goats in summer. However, the responses in digestibility, rumen fermentation, and blood metabolites appear to indicate the potential of rebaudioside A as a bio-active substance in goats.     

A free-choice intake of mineral blocks in beef cows during the grazing season and in winter

A herd of 25 beef cows were offered four types of mineral blocks (A, B, C, D) with a different Ca to P ratio (A 0.6:1, B 0.8:1, C 2:1 and D 3.6:1). The Mg content was identical in all blocks whereas the Na content was equal in B, C and D, while the Na content in A block was double. The mineral block intake was monitored for 1 year, which was broken down to the grazing period (Pa) and the winter period (Wi). The intake of pasture grass and winter forage was assessed and the feed chemical composition was analysed; based on the obtained values, a macroelement balance (for Ca, P, Mg, Na and K) was calculated.The results showed the forage diet met requirements for all the observed macroelements (except in Na). The macroelement intake from forage was considerably higher than from mineral blocks. There were significant seasonal (Pa versus Wi) differences in B and C blocks intake. The consumption of D block was relatively invariable all year round; block A was refused in both seasons though it contained the highest amount of highly deficient Na.It can be concluded that mineral content in forage meets beef cattle requirements for Ca, Mg and K, P content is just satisfactory, and Na content is insufficient. It appears that cows control, to some extent, the Ca to P ratio in their diet by choosing the appropriate type of mineral block. However, the preference or refusal of some types of mineral blocks regardless of the season suggests the influence of other factors affecting mineral block intake which were not the subject of our observation.     

新疆地区荷斯坦干奶牛与泌乳牛四季NH3排放量变化的研究

试验于2011年7月～2012年7月在同一栋牛舍内对20头干奶牛和20头泌乳牛分别进行了四季氨气排放量测定,每个季节根据气象信息所提供的当地气温,分别在季前、季中、季末共选取气温相近的18d,分别对干奶牛（9d）与泌乳牛（9d）进行监测。通过测定不同时间段牛舍内NH3的浓度,把3次实测值进行累加,计算出24h奶牛NH3的排放值。结果表明,四季试验期间干奶牛舍内平均NH3排放量是6．42g／（头·d）,四季泌乳牛舍内平均NH、排放量是10．62g／（头·d）。四季温度的变化对奶牛排放NH3有一定的影响。奶牛NH3的排放量与奶牛的采食量、饲料配方和饲料中CP水平有关,一头体重500kg左右的奶牛一年产生约3．6kg的氨气：     

AN EXAMINATION OF THE SELENIUM NUTRITION OF SHEEP IN VICTORIA

The selenium nutrition of sheep throughout Victoria was assessed by a survey of the blood glutathione peroxidase activity in 708 flocks. It was shown that the blood glutathione peroxidase activity in sheep had a seasonal variation with lowest levels in the spring. The enzyme activity was correlated with the blood selenium concentration. Areas where blood selenium was less than 0.03 μg/ml in spring were defined. Sheep with low selenium nutrition were grazing pastures in the high rainfall areas on acid soils, particularly those derived from granite.
Selenium concentrations in pasture samples examined were greater than 0.02 mg/kg, and it was found that superphosphate application had no significant effect on the selenium content of pasture. However, management practices such as high stocking rates and rates of application of superphosphate to pasture were associated with low blood glutathione peroxidase activities in sheep.
It was concluded that the selenium nutrition of most of the sheep flocks in Victoria is adequate, and that the deficient areas are localised. There seems little requirement for supplementation of adult sheep. As the delayed type of white muscle disease in spring lambs appears to be the main selenium-responsive disorder, direct supplementation of lambs in the low selenium areas would be the most effective method of ensuring adequate selenium nutrition.