Specific immunoglobulins in serum of newborn lambs fed with a single dose of colostrum containing anti-peroxidase IgG

The apparent efficiency of absorption and the decrease of specific colostral IgG after its passage into the blood stream were determined in newborn lambs fed with a single dose of colostrum containing anti-peroxidase IgG at 30 minutes, 12 hours and 24 hours after birth. When colostrum was given at 30 minutes after birth, a value of 16.9+/-4.0 per cent of anti-peroxidase IgG ingested appeared in lamb circulation. This percentage was reduced to 9.8+/-0.8 per cent when the feeding was done at 12 hours after birth and no specific IgG was detected in lambs fed at 24 hours after birth. The concentration of anti-peroxidase IgG in lambs' serum declined quickly within 96 hours of age to about 48 per cent of the initial value, and afterwards the level decreased slowly reaching a value of 10 per cent at 32 days of age. This behaviour probably reflects the protein distribution and use of absorbed antiperoxidase IgG.     

Effects of maternal nutrition on udder development during late pregnancy and on colostrum production in Scottish Blackface ewes with twin lambs

Effects on udder development and colostrum production of changing the level of ewe nutrition were investigated. Udder weights at term were derived from their linear dimensions and yields of colostrum were obtained by hand milking on three occasions between one and 18 hours after birth. The linear dimensions of the udder increased progressively in all animals between 100 days of gestation and term (about 145 days), but udder development was retarded significantly within three days of the onset of underfeeding at 105 days of gestation. Underfeeding reduced the total yield of colostrum during the first 18 hours after birth by decreasing the prenatal accumulation of colostrum and its subsequent rates of secretion. Improving the ewe's nutrition from one hour after birth tended to increase the secretion rates of colostrum between 10 and 18 hours. Refeeding previously underfed ewes to high levels from about five days before birth had no effect on udder growth but did increase the prenatal accumulation of colostrum and its subsequent rates of secretion to levels which, when corrected for differences in udder weight, were similar to those of ewes which were fed well throughout. Calculations revealed that by ignoring udder growth the Agricultural Research Council recommendations for the energy requirements of pregnant ewes underestimate the cost of tissue synthesis during the last four weeks of pregnancy by about 100 per cent.     

Vitamin E status in newborn lambs with special reference to the effect of dl-alpha-tocopheryl acetate supplementation in late gestation

Pregnant ewes were supplemented with dl-alpha-tocopheryl acetate, either as a single intramuscular dose (500 mg two weeks before lambing) or perorally (150 mg daily during 3-4 weeks before lambing). Ewes without such a supplementation were controls. The vitamin E supplemented ewes had nearly twice as high vitamin E (alpha-tocopherol) concentrations as the unsupplemented control ewes at lambing both in serum and in colostrum. The vitamin E concentration in colostrum was 5-11 higher than in milk 1 week after lambing. Both supplementations somewhat increased the vitamin E serum concentration of the newborn lambs, but the increase was negligible in comparison with the effect produced by the consumption of colostrum. All lambs had very low serum concentrations at birth. The lambs from the supplemented ewes had significantly higher serum values than the control lambs 24 h after birth. The ewes had somewhat higher selenium status at birth than their offsprings when evaluated by glutathione peroxidase (GSH-Px) in the erythrocytes. It seems reasonable that nutritional muscular degeneration may arise in newborn lambs with a normal selenium status if their vitamin E status is critical, either because of an inadequate consumption of colostrum or because of a vitamin E deficient diet during pregnancy with a low vitamin concentration of colostrum as a consequence.     

Making the most of colostrum at lambing

Lambs require between 180 and 210 ml colostrum/kg bodyweight during the first 18 hours after birth in order to provide sufficient fuel for heat production. Colostrum intakes of this order would usually provide enough immunoglobulins for protection against infections. Ewes which are well fed during late pregnancy produce more colostrum than their lambs need, those with singletons having enough for a second lamb, but in most underfed ewes the lamb's requirements for colostrum exceed the ewe's production. Colostrum can be readily obtained and stored for subsequent use. The yields are increased markedly when hand milking is preceded by an oxytocin injection, the intravenous dose being 5 iu and the suggested intramuscular dose being 10 to 15 iu. There is little practical benefit in milking ewes more than three times during the first 18 hours after birth.     

High mineral and vitamin E intake by pregnant ewes lowers colostral immunoglobulin G absorption by the lamb

A 2 x 2 factorial arrangement of treatments with 78 mature ewes was used to evaluate the effects of supplementing the pregnant ewe's diet with high levels of minerals and vitamin E on immunoglobulin G (IgG) absorption by the lamb and whether any altered efficacy of IgG absorption was due to the colostrum or to the lamb. The ewes were estrus-synchronized in October and housed in wk 10 of gestation. In the final 7 wk of gestation, a grass silage-based diet, offered ad libitum, was supplemented with 500 g of a 19% CP concentrate, and from 1 wk later until lambing, half the ewes was offered 48 g of a mineral/vitamin supplement containing 6.5 g of Ca, 4.9 g of P, 5.9 g of Mg, 4.0 g of Na, 790 mg of Zn, 3.5 mg of Se, 40 mg of I, 200 mg of Mn, 20 mg of Co, and 40 IU of vitamin E. At birth, the lambs were allocated to one of four treatments in a 2 x 2 factorial arrangement, with lamb origin and colostrum origin as the two factors. The lambs born to ewes not offered the mineral supplement were fed colostrum obtained from their own dams or from ewes in the mineral-supplemented treatment, whereas lambs born to ewes given supplemental minerals were fed colostrum obtained either from their dams or from ewes in the control treatment. The ewes were milked at 1, 10, and 18 h postpartum and the lambs were fed using a stomach tube. A 5-mL blood sample was taken from each lamb at 24 h postpartum for IgG analysis. The level of fecal adhesion to the upper tail/rump area of the lamb was subjectively scored at 72 h postpartum. There was no difference in gestation length, lamb birth weight, colostrum yield, or IgG production (P = 0.16 to 0.82). When ewes were fed supplemental minerals, the serum IgG content of the progeny was lower than in their control counterparts (6.8 vs. 16.1 g/L; P < 0.001), regardless of whether the lamb received colostrum from ewes with or without access to supplementary minerals. The difference in serum IgG concentrations at 24 h postpartum was a direct reflection of a compromised efficiency in IgG absorption. The progeny of ewes with access to minerals had higher (P < 0.05) levels of fecal adhesion, which was not related to the origin of the colostrum, indicating altered digestive function in these lambs. We conclude, using the sheep as a model, that high mineral intakes in late pregnancy not only lower serum IgG concentrations in the lamb, but also that high mineral intakes result in the neonate being preprogrammed at birth so that it is born with a compromised ability to absorb colostral IgG.     

Effects of gestational plane of nutrition and selenium supplementation on mammary development and colostrum quality in pregnant ewe lambs

To examine effects of nutritional plane and Se supplementation on colostrum quality and mammary development, individually fed, pregnant Rambouillet ewe lambs were allotted randomly to 1 of 6 treatments in a 2 x 3 factorial arrangement. Main effects included dietary Se level, which began at breeding (d = 0) [adequate Se (9.5 mug/kg of BW) vs. high Se (81.8 mug/kg of BW)], and plane of nutrition, which began at d 50 of gestation [60% (RES), 100% (CON), and 140% (HIGH) of requirements]. Upon parturition, lambs were immediately separated from dams and weighed. Three hours after lambing, colostrum yield was determined, and samples were obtained for components and immunoglobulin G (IgG) analysis. Ewes were slaughtered within 24 h of parturition, and mammary tissues were collected for determination of alveolar secretory epithelial cell proliferation index and luminal area. Gestation length was reduced (P < 0.01) in HIGH ewes compared with RES and CON ewes. Although birth weights were reduced (P < 0.01) in RES and HIGH compared with CON ewes, there was little effect of diet on placental size. Mammary gland weight was reduced (P /= 0.15) on mammary gland weight, colostrum quantity, or IgG concentration in pregnant ewe lambs. Improper nutrition from mid to late pregnancy in ewe lambs altered colostrum quality and quantity and reduced offspring birth weight, which may have negative implications for lamb health and survival during the early postnatal period.     

Frequency and cost of human intervention at lambing: an interbreed comparison

The frequency of human intervention during lambing was assessed for 708 lambs and 162 ewes in up to four deliveries. In total, 21.8 per cent of the lambs born alive required some assistance at birth and 9.4 per cent were delivered manually. Assistance was required less frequently by twin lambs and ewe lambs, and Scottish blackface lambs required assistance less frequently than Suffolk lambs. Approximately one-third of the ewes were assisted in at least one delivery and 10 per cent were assisted in all their deliveries; however, less than 20 per cent of ewes were assisted more than once. A quarter of the lambs needed some human intervention to suck successfully, and Suffolk lambs needed help more frequently. The lambs born to almost half the first-parity ewes needed help to suck, but at later deliveries the lambs born to less than a third of the ewes needed assistance. In blackface flocks the survival of 100 lambs required 4.6 hours of human intervention whereas in Suffolk flocks 28 hours were required.     

Intrauterine transmission of ovine progressive pneumonia virus

Ovine fetuses, newborn lambs, and ovine colostrum were examined for ovine progressive pneumonia virus. The lambs and colostrum were also examined for specific antibody. Virus was isolated from 1 fetus, from 2 newborn lambs, and from most samples of colostrum. The fetus was about 100 days old and was carried by a seronegative ewe in contact with seropositive sheep. Both newborn lambs were carried by seropositive ewes. One lamb was dead at birth; the other lamb was normal and had not nursed. Antibody specific for the virus was present in the colostrum of 12 of 14 seropositive ewes and in the serum of 8 of 11 lambs that had nursed seropositive ewes, but not in the serum of lambs that had not nursed.     

Computer model of the absorption and distribution of colostral immunoglobulins in the newborn calf

The transfer of immunoglobulin (Ig) isotypes (IgG1, IgG2, IgM), gamma-glutamyl transpeptidase (gamma-GT) and added D-xylose from colostrum to serum was investigated in newborn Holstein bull calves. Significant differences were observed in the time courses of the serum concentrations of these colostrum constituents following absorption from pooled colostrum. A computer model was devised to simulate the process of absorption of Ig isotypes, gamma-GT and D-xylose from colostrum in the newborn calf. A Fortran program was used to generate plots of the time course of the concentration of colostrum constituents in serum and other body fluids following a single feed of colostrum. These plots show how the changes in serum concentration of absorbed Ig isotypes, gamma-GT and D-xylose are affected by different rates of intestinal absorption, redistribution in body fluids and removal from plasma. A critical examination of data from the computer model and from the calf feeding experiments supports the view that the absorption of IgG1, IgG2 and IgM is not selective in the calf. The data were compared with earlier studies of the efficiency of the colostral transfer of Ig to the calf. In the present study the transfer efficiencies of IgG1, IgG2, IgM, gamma-GT and D-xylose were 46 per cent, 49 per cent, 47 per cent, 18 per cent and 21 per cent, respectively.     

Effect of Energy Levels During Late Gestation on the Ewe Health and Growth Performance of Lambs

The late pregnancy is a critical period of fetal growth and development. As approximately 80% of fetal body weight is obtained during late gestation, so that the amount of energy needed for the ewes at this period is much greater than the other periods. Now ewes with multiple fetuses are mutton sheep breeding cultivation objectives, however,under the grazing or confined feeding conditions where nutrient requirement can't satisfy the nutrient requirement of sheep, especially for pregnant ewes with twins or more lambs.The body glycogen and protein as well as body fat will be mobilized for energy needed for the fetal growth and reproduction, which would lead to bad influence on ewes (metabolic disorders, liver function damage, pregnancy toxemia, embryonic development and health) and also on lamb (weak lamb, dead lamb and health). Therefore, investigating the effects of dietary energy levels during late gestation on the ewe's health and growth performance of lambs are essential for the sustainability of livestock production systems. This review summarized the effect of different energy levels on the ewes' health, reproductive performance of the ewes, lactation performance, embryo development and the growth of lambs, then expounded the roles of energy in later gestation. When the dietary energy of ewes in late gestation are restricted, the weight, breast development, lactation capacity, pregnancy rate will all be decreased, and the growth rate and organ development of embryos and lamb will also be restricted.     

Immunoglobulin levels in ewe colostrum and in lamb serum

The immunoglobulin content of ewe colostrum falls rapidly after the first suckling and reaches a low level 36 h after the first feed. The whey content of colostrum will rise by more than 50 per cent during the same period. The production of colostral immunoglobulin during the 24 h following the first feed was related, in this work, to the amount of colostrum produced; the greater the colostrum production, the greater the immunoglobulin production. Colostrum production ranged from 1216 to 4493 g and immunoglobulin production from 22-21 to 86-34 g during the eight feeds studied. Colostrum production was related to demand by the lambs. There was a clear positive correlation between the total amount of immunoglobulin the lambs' circulation 30 h after the first feed and the immunoglobulin consumed. Approximately 20 to 25 per cent of the immunoglobulin ingested was present in the lambs' circulation at this time.     

能量对妊娠后期母羊健康及其羔羊的影响

妊娠后期是胎儿生长发育的关键时期,胎儿体重增长的80%在此阶段完成,因此该阶段母羊的能量需要量大于其他生理阶段。高产多胎是肉用种母羊的重要培育目标,当母羊处于营养水平较低的草场或舍饲条件下,怀双羔或多羔母羊的日粮能量水平不能满足其营养需要时,母羊会动用体内的糖原、体蛋白和体脂以弥补能量不足,致使母羊的代谢紊乱,肝机能受损,产生羊妊娠毒血症,影响母羊的健康和胚胎的健康生长,产出弱羔、病羔,并可能影响产后羔羊的健康生长。因此,研究妊娠后期能量水平对母羊健康、胚胎发育、羔羊生长及肉羊养殖业的发展都有重要的指导意义。作者对不同能量水平对妊娠母羊的健康、繁殖性能、泌乳性能、胚胎与羔羊生长的影响展开讨论,阐明妊娠后期能量的作用。当母羊妊娠后期能量受到限制时,母羊的体重降低,乳腺发育受阻,泌乳能力下降,受胎率下降;同时胚胎的生长速度降低,影响胚胎与产后羔羊组织器官发育和正常生长。     

Nitrogen metabolism by lactating ewes and their lambs

Twenty multiparous ewes and their newborn lambs were assigned to a 2 x 2 factorial experiment in which ewes were fed ad libitum either a moderate (MP, 15%) or a low (LP, 10%) CP diet and nursed either twin (T) or single (S) lambs. Nitrogen (N) balance trials were conducted on both the ewes and lambs during wk 2, 4 and 8 of lactation. Nitrogen balance, N digested and the portion of digested N retained were greater (P less than .01) with the MP diet. Nitrogen retention and serum urea-N values were lower for the ewes nursing T lambs. Plasma beta-hydroxybutyrate and serum glucose values were lower (P less than .01) for ewes fed the LP diet, and certain plasma amino acids and the ketogenic amino acids were lower with the LP diet. Insulin increased (P less than .01) with time throughout lactation. Triiodothyronine (T3) concentrations were higher (P less than .01) in ewes nursing T lambs. Thyroxine (T4) was greater (P less than .04) with the LP diet and greater (P less than .01) for ewes nursing T lambs. The T4:T3 ratio was lower (P less than .02) in the ewes consuming LP. The portion of the ewe's retained N used for milk synthesis was lower (P less than .01) with the MP diet. Ewes fed LP and nursing T lambs utilized all of their retained N plus a portion of their body protein reserves for milk production by the 2nd wk of lactation. Body weights of creep-fed lambs were not changed by protein content of the ewe's diet.     

Isoenzymes of alkaline phosphatase in serum of lambs and ewes.

Electrophoresis in polyacrylamide gels was used to identify isoenzymes of serum alkaline phosphatase in sheep. Skeletal isoenzyme predominated in the serum of lambs and liver, skeletal and intestinal isoenzymes were found in the serum of adult ewes. In r ewes (R-r-i blood group system) intestinal isoenzyme activity was 67 per cent of total serum activity; in R ewes intestinal activity was only 36 per cent of total activity. Relative activities of the three isoenzymes differed greatly within individual ewes and between individual ewes during pregnancy and lactation.     

Colostral transmission of maedi visna virus: sites of viral entry in lambs born from experimentally infected ewes

Maedi visna virus (MVV) vertical transmission in sheep via infected colostrums is a very important route of infection in lambs. To verify colostral transmission and to study early viral entry in lambs, colostrum samples, and small intestine and mesenteric lymph nodes of lambs born from experimentally infected ewes were examined by histopathology, immunohistochemistry (IHC) and in situ hybridisation (ISH) studies. In particular, newborn lambs were naturally fed maternal colostrum and humanely killed at 10, 24, 48, 72, 96 h and 7 and 10 days after birth; two caesarian-derived lambs served as uninfected controls. No lesions suggestive of MVV infection were found, but marked immunoreactions for MVV capsid antigen (CA, p28) were detected in lambs fed maternal colostrum and in macrophages cultured from colostrum. IHC results in lambs suggest an initial viral absorption by intestinal epithelial cells at the tip of the villi, passage to mononuclear cells in the lamina propria and involvement of ileum Peyers' patches and mesenteric lymph nodes, with different staining patterns depending on infection times. ISH on intestinal sections of the 72 h lamb revealed the presence of proviral DNA in epithelial cells at the tip of the villi, suggesting a role for these cells in early MVV replication. The results contribute to knowledge about the pathogenesis of ovine lentivirus infection suggesting that the small intestine and mesenteric nodes are the sites of entry and propagation of MVV in lambs fed colostrums from infected ewes.     

A field study of watery mouth: clinical, epidemiological, biochemical, haematological and bacteriological observations

More than 500 cases of watery mouth in newborn lambs were recorded in 11 flocks and a detailed examination was performed in more than 200 cases. The condition occurred predominantly in lambs aged 24 to 48 hours. The incidence in a flock varied from 1 per cent to 24 per cent and the mortality in affected lambs varied from 7 per cent to 83 per cent. A bacteraemia was found in 38 per cent of the affected lambs. There were no consistent abnormalities of clinical biochemistry or haematology. Watery mouth was more common in twins and especially in triplets than in single lambs. In twins the highest incidence of watery mouth was recorded in lambs born to ewes in poor body condition. Antibiotic given orally within 15 minutes of birth greatly reduced the incidence of watery mouth.     

Does sward height grazed by ewes in mid- to late-pregnancy affect indices of colostrum intake by twin and triplet lambs?

AIMS: To determine if sward height grazed by ewes in mid- to late-pregnancy affects subsequent indices of colostrum intake by twin and triplet lambs, and the extent of the variation in colostrum intake between twin and triplet litter-mates.

METHODS: Blood samples were collected from 75 twin and 46 triplet litters, respectively, 24–36 h after birth. Samples were not collected from lambs that died before this age. Lambs were born to ewes which had grazed one of four sward heights (2, 4, 6 and 8 cm) during mid- to late-pregnancy. Serum samples were analysed for gamma-glutamyl transferase (GGT) activities and glucose concentrations. The number of lambs present at weaning was used to determine lamb survival rate.

RESULTS: GGT activities of lambs born to ewes that grazed swards 2 cm high were lower than those born to ewes that grazed swards 4 and 6 cm high (p=0.053 and p=0.037, respectively). Glucose concentrations were higher in twin than triplet lambs (p=0.003) and in lambs born to ewes grazed on swards 6 cm high than those born to ewes grazed on swards 2 cm high (p=0.033). These differences were not evident after correction for differences in birthweight. There was significant (p<0.001) variation within litter-mates for GGT activities and glucose concentrations in both twins and triplets. The blood constituent status of lambs that died before the 24–36 h collection period is not known. However, lambs which died after this period had significantly lower GGT activities (p=0.009) and glucose (p=0.010) concentrations at the time of sampling than those which survived.

CONCLUSIONS: Farmers should ensure twin- and tripletbearing ewes in mid- to late-pregnancy are grazing at least 4 cm of herbage to ensure colostrum intake of lambs in the postpartum period is not adversely affected.     

Vaccination of sheep with a live incomplete strain (S48) of Toxoplasma gondii and their immunity to challenge when pregnant

Sixty-four ewes were vaccinated with tachyzoites of an incomplete strain (S48) of Toxoplasma gondii grown either in the peritoneal cavity of mice (group 1) or vero cell culture (group 2) and 30 ewes (group 3) were not vaccinated. All the ewes were mated 77 days later and challenged orally with 2000 sporulated oocysts at 89 to 90 days of gestation. Ten additional unvaccinated (group 4) and 10 vaccinated (group 5) control ewes were not challenged. The unvaccinated ewes developed a characteristic febrile response to challenge while in the vaccinated ewes the fever commenced earlier but was less severe and of shorter duration. After challenge, the antibody titres against T gondii rose rapidly to high values in the vaccinated ewes while the ewes in group 3 responded more slowly. Only eight of the 45 fetuses/lambs (17.8 per cent) from group 3 were viable compared with 72.3 per cent of those in group 1 and 80.8 per cent of those in group 2. Gestation in the unvaccinated challenged ewes was shortened and the mean birthweight of their single, viable offspring was significantly lower than the weight of single lambs from the vaccinated (groups 1 and 2) and control ewes (groups 4 and 5). Examination of precolostral sera showed that almost two-thirds of the lambs from the vaccinated ewes were infected in utero. The 20 control ewes appeared clinically normal at all times and lambed normally. The two vaccine preparations were equally effective.     

Case-control study of orf in preweaned lambs and an assessment of the financial impact of the disease

Orf, a viral disease which causes proliferative skin lesions around the mouths of lambs and on the teats of ewes, has long been assumed to have production-limiting consequences. This case-control study involved the collection of data from naturally occurring outbreaks of orf in young lambs on eight commercial farms in north-east England. Measurements of weight were taken and orf lesions were scored on a numerical scale for 44 orf-affected lambs, matched to unaffected controls within the same group. Data from corresponding ewes were available from five farms. Paired t tests showed that affected lambs weighed approximately 10 per cent less than their unaffected controls for a period of at least five weeks following the start of the outbreak. The effects were highly significant whether the orf lesions affected the mouth or were found elsewhere on the body. If a lamb had orf, then there was a 82 per cent chance that its mother also had orf on its udder or teats. The financial consequences of orf in young lambs were estimated using average UK figures and conservative assumptions based on the results of this study.     

Colostrum production by ewes and the amounts ingested by lambs

Studies involving 49 ewes which were well nourished during the last eight weeks of pregnancy indicated that ewe weight loss during pregnancy and lamb birth weights followed the recognised pattern and were within acceptable "normal" limits. Colostrum production ranged from 1238 to 4593 g per ewe during the 48 h following the first suckling and there was evidence that production levels were related to demand by the lambs. Colostrum consumption by individual lambs was related to litter size. The smaller the litter size the greater was the amount ingested during the first 48 h of life. No clear relationship was established between the amount of colostrum consumed and the level of immunoglobulin in a lamb's circulation. Possible reasons for this are discussed.