Changes in ovine maternal temperature, and serum cortisol and interleukin-6 concentrations after challenge with Escherichia coli lipopolysaccharide during pregnancy and early lactation

Major changes in maternal physiology during pregnancy and lactation can have a large impact on the immune and neuroendocrine systems. One of the most significant changes, observed in rats and mice, is hyporesponsiveness of the hypothalamic pituitary adrenal axis (HPAA) in response to inflammation, restraint, and other psychological stressors during late pregnancy and lactation. This attenuation, however, has not been well characterized in ruminant animals and may be relevant to their susceptibility to inflammatory diseases during these periods. Thus, the intent of this study was to characterize responsiveness of the ovine HPAA to inflammatory challenge during pregnancy and lactation. Ewes from early (33 d), middle (55 d), and late (138 d) pregnancy, as well as early lactation (10 d), were challenged i.v. with a bolus dose of 400 ng of Escherichia coli lipopolysaccharide (LPS)/kg of BW or saline. A corresponding group of nonpregnant ewes was also challenged with LPS to serve as positive control animals for each pregnancy and lactation study. Responsiveness of the HPAA was assessed by measuring the 4-h change in serum cortisol concentration after LPS challenge. The cortisol increase after LPS challenge was elevated (P < 0.01) in pregnant ewes during late pregnancy over that of nonpregnant animals. In contrast, the characteristic temperature response associated with systemic LPS challenge was decreased (P < 0.01) during early pregnancy and lactation compared with nonpregnant or nonlactating animals. Serum IL-6 concentrations were measured to assess whether changes in HPAA responsiveness during pregnancy or lactation were attributed to changes in proinflammatory signaling to the HPAA. Interestingly, enhanced cortisol responsiveness during late pregnancy was correlated with increased (P < 0.01) serum IL-6 concentrations, indicating that IL-6 may contribute to enhanced HPAA responsiveness during this period. Serum IL-6 concentrations during early and midpregnancy did not increase in response to LPS challenge, indicating that HPAA activation during periods of pregnancy may be independent of IL-6 production.     

Electrophoretic serum protein fraction profile during the different physiological phases in Comisana ewes

The aim of this study was to evaluate the influence of different physiological phases on serum total proteins and their fractions of ten Comisana ewes housed in Mediterranean area. From each animal, blood samples were collected at different physiological phases: late pregnancy, post-partum, early, mid-, end lactation and dry period. On all samples serum total proteins were determined by the biuret method, and albumin, α-globulins, β(1) -globulins, β(2) -globulins and γ-globulins concentrations were assessed using an automated system. One-way repeated measures analysis of variance was applied to determine the significant effect of different physiological phases on the parameters studied. During the late pregnancy and post-partum, total proteins, β1- and β2-globulins and γ-globulins showed the highest values. Starting from post-partum, α-globulins increased to reach their peaks in mid-lactation. Early lactation was characterized by low γ-globulins values. The increase in serum albumin concentration and the drop in some globulin fractions determined the significant increase in albumin/globulin ratio. The obtained results contributed to improve the knowledge on electrophoretic profile during the different physiological phases in ewes, confirming that pregnancy and lactation periods affect the protein metabolism. Particularly, serum protein fractions pattern could give information about dehydration, plasma volume expansion and hepatic function, which occur during the different physiological phases. Dynamics of the protein profile - from pregnancy to dry period - which are provided by our results, could be considered as guidelines for the management strategies to guarantee the nutritional needs of these animals during the different physiological phases and to avoid a decline of productive performance and consequently an economic loss.     

The influence of physiological state and dietary nitrogen supply on digestion in the dairy cow

The effects of N supply on digestion were compared in cows in late pregnancy vs early lactation. Two groups of four and one group of three dairy cows received, during a digestion trial, corn silage-concentrate diets (65:35) differing in N supply. Concentrates were formulated so that diets were either insufficient (Diet 1) or sufficient (Diets 2 and 3) in ruminally fermented N and either insufficient (Diets 1 and 2) or sufficient (Diet 3) in protein digestible in the intestines. Experimental periods were 3 wk before and 3 wk after parturition. Organic matter digestibilities were 69.8, 73.1 and 72.5% in late pregnancy vs 64.9, 69.8 and 70.8% in early lactation for Diets 1, 2 and 3, respectively. Digestibility was higher (P less than .05) in late pregnancy than in early lactation. Differences between physiological states were attributed to differences in ruminal digestibility and in fiber digestibility. These differences were not explained by a reduction in large particle retention time, but in situ DM disappearance was reduced in early lactation. Ruminal protozoa concentration and the acetate: propionate ratio decreased between pregnancy and lactation. The duodenal non-ammonia N:N intake ratio was higher for Diet 1 than for Diets 2 and 3, 1.20, .97 and .94, respectively, but it did not vary between physiological states. In conclusion, some of the negative consequences of a shortage in degraded N are more dramatic in early lactation than in late pregnancy.     

奶牛不同生理阶段血清微量元素含量和氧化状态

选择3～4月龄犊牛、后备母牛和成年母牛(产奶后期、产前及产后1月内).测定了血清Se、Cu、Zn、Mn、Fe含量厦谷胱甘肤过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性和丙二醛(MDA)含量.结果表明,除Zn含量外,所测元素含量犊牛明显低于后备母牛和成年牛(P<0.05或P<0.01),后备母牛和成年牛之闻差异不显著(P>0.05),血清Se含量在产奶后期和产前明显下降(P<0.05),血清Cu、Mn含量在产后1月内有降低的趋势,但与产前相比均差异不显著(P>0.05);所测血清氧化状态指标与年龄无明显关系,在妊娠末期和泌乳早期发生改变,血清CAT、GSH-Px、SOD活性和MDA含量在产前和产后1月内最高.表明犊牛上述所测指标最低,奶牛产前和泌乳早期血清微量元素含量和氧化状态失衡.     

苷元型大豆异黄酮对母羊氧化应激、乳中免疫球蛋白和羔羊生长的影响

本试验旨在研究日粮中添加不同水平的苷元型大豆异黄酮对妊娠后期及泌乳期母羊氧化应激、乳中免疫球蛋白和羔羊生长的影响。试验选用33只年龄、体重、胎次相近的妊娠100 d的崇明白山羊,随机分为3组,对照组饲喂基础日粮(C0组,11只),试验组分别在基础日粮中添加20 mg/kg(T1组,9只)和30 mg/kg(T2组,13只)苷元型大豆异黄酮。结果表明:T1和T2组母羊的窝产羔数、初生窝重、断奶窝重和窝日增重显著高于C0组(P0.05);分娩当日,T2组母羊血清中过氧化氢(H_2O_2)含量显著低于C0和T1组(P0.05);与T1和T2组相比,C0组血清中总超氧化物歧化酶(T-SOD)活性最高(P0.05),总抗氧化能力(T-AOC)最低(P0.05),3组间丙二醛(MDA)无显著差异(P0.05);在泌乳21 d,T2组母羊血清中H_2O_2含量显著低于C0和T1组(P0.05);与C0和T2组相比,T1组血清中T-SOD活性最高(P0.05),3组的T-AOC和MDA无显著差异(P0.05);T1和T2组初乳中免疫球蛋白A(Ig A)含量显著高于C0组(P0.05)。结果提示,在妊娠后期及泌乳期母羊饲粮中添加苷元型大豆异黄酮可有效减缓母羊的氧化损伤,提高初乳中免疫球蛋白含量,促进羔羊生长发育,且添加量以30 mg/kg效果更显著。     

The hypocalcemic response to protamine as a measure of bone resorption

The heparin antagonist protamine inhibits bone resorption. In the present study protamine was given i.v. at a dose of 10 mg/kg to goats and sheep in various stages of pregnancy and lactation. It is known that bone resorption increases as pregnancy progresses. In sheep maximum in bone resportion is reached at early lactation. The hypocalcemic response to protamine followed a similar course. The slightest decrease in serum calcium was obtained during early pregnancy and the greatest during late pregnancy and early lactation. Protamine increased serum inorganic phosphorus. The increase was most pronounced during early pregnancy. Protamine did not significantly change serum magnesium.Five lactating ewes were given 25000 i.u./kg of vitamin D3. Serum calcium increased and the hypocalcemic response to protamine was greater after vitamin D₃ administration than before.The results showed that the hypocalcemic response to protamine can be used as an indicator of the role of bone resorption in calcium homeostasis in various physiological situations.     

Seasonal variations in the gastro-intestinal nematode populations of Scottish hil sheep.

In each of two consecutive years, groups of breeding ewes were removed from a hill farm in the west of Scotland on four occasions, namely late pregnancy, early lactation, autumn and early winter. At slaughter the major nematode genus present in the alimentary tract was Ostertagia, with O circumcincta the predominant species but three species previously found in Scottish hill sheep, Bunostomum trigonocephalum, Strongyloides papillosis and Chabertia ovina were absent. An absolute increase in total nematode burden and faecal egg count was apparent in the ewes commencing in late pregnancy, reaching a maximum during lactation and falling again in autumn and early winter. This peri-parturient increase in the nematode population could not be solely attributed to the maturation of previously inhibited larval stages but was primarily the result of the development of recently ingested infection; the latter situation thought to be due to a temporary relaxation of immunological response by the ewe at parturition or early lactation. Serum pepsinogen values in ewes remained elevated throughout the grazing season and were always higher than those of their lambs, suggesting that the ewe, although allowing few parasites to become established, was under considerable challenge in the autumn. The worm burdens of the lambs were always low in autumn and early winter with Ostertagia spp being the major genus present during the autumn and Trichostrongylus spp being the predominant genus during the early winter.     

Changes in serum concentrations of methylmalonic acid and vitamin B12 in cobalt-supplemented ewes and their lambs on two cobalt-deficient properties

AIM: To determine concurrent changes in serum methylmalonic acid (MMA) and vitamin B12 concentrations of ewes and their lambs on cobalt-deficient properties, subsequent to cobalt supplementation. METHODS: Three experiments were carried out on two farms. Groups of ewes (n=25-50) were either supplemented with cobalt bullets during late pregnancy, 23-47 days before the mean lambing date, or left unsupplemented. In two experiments, lambs from within each group were supplemented directly by vitamin B12 injection at 3-weekly intervals from birth, and in the third experiment by injection with micro-encapsulated vitamin B12 at tailing and 3 months later. Pasture samples were obtained for analysis of cobalt content at each sampling time. Blood samples were obtained and liveweight recorded from ewes and lambs at approximately monthly intervals. On one farm (two experiments), liver and milk samples were obtained from ewes and liver samples from lambs. RESULTS: Serum vitamin B12 concentrations in unsupplemented ewes fell below 250 pmol/L during early lactation in all experiments and mean concentrations as low as 100 pmol/L were recorded. MMA concentration was maintained below 2 micromol/L in serum from supplemented ewes but increased to mean concentrations ranging from 7 to 14 micromol/L at the nadir of serum vitamin B12 concentration during peak lactation. A significant liveweight response to supplementation was recorded in ewes on one property, and the vitamin B12 concentration in the ewes' milk and in the livers of their lambs more than doubled. No liveweight-gain response to supplementation was observed in lambs on this property. Mean serum MMA concentrations in lambs ranged from <2 in supplemented, to 19.2 micromol/L in unsupplemented lambs, and the latter had concurrent serum vitamin B12 concentrations of >300 pmol/L. Pasture cobalt concentration was lowest at 0.04-0.09 microg/kg dry matter (DM) on the property on which responses in lambs occurred but considerably higher (>0.09 microg/kg DM) on the property on which responses in ewes occurred. On the second property, serum vitamin B12 concentrations in lambs at tailing were extremely low (100 pmol/L), irrespective of supplementation of dams with cobalt. Mean serum MMA concentration was increased to 20 and 42 micromol/L in lambs from supplemented and non-supplemented ewes, respectively. Weight-gain response to direct supplementation of lambs with vitamin B12 occurred during suckling in the latter, but not the former. Lambs from ewes supplemented with vitamin B12 showed a much bigger increase in serum vitamin B12 concentrations a month after supplementation than did lambs from unsupplemented ewes (+1,400 pmol/L vs + 650 pmol/L). CONCLUSIONS: Serum MMA concentration gave a more precise indication of responsiveness to vitamin B12 or cobalt supplementation than serum vitamin B12 concentrations in ewes and lambs. Neither very low serum vitamin B12 nor elevated MMA concentrations were necessarily indicative of responsiveness to supplementation in suckling lambs, but the latter gave an early indication of impending responsiveness. Supplementation of the ewe with a cobalt bullet appeared to protect the growth performance of the lamb for 90 days and influence the subsequent serum vitamin B12 response in the lamb to vitamin B12 supplementation. CLINICAL SIGNIFICANCE: Supplementing ewes with cobalt bullets in late pregnancy can improve the vitamin B12 status of their lambs, and modify their response to vitamin B12 supplementation.     

Influence of milk production potential on forage dry matter intake by multiparous and primiparous Brangus females

Brangus cows (n = 29) were used in three experiments to evaluate the effects of parity (multiparous vs. primiparous) and potential genetic merit for milk production (high vs. low) on forage intake during late gestation, early lactation, and late lactation. Cows were selected for milk production based on their sire's EPD for milk production (MEPD). Cows had ad libitum access to (130% of previous 2-d average intake) low-quality hay (5.3% CP and 76% NDF), and cottonseed meal was supplemented to ensure adequate degradable intake protein. All females were adapted to diets for at least 7 d, and individual intake data were collected for 9 d. During the lactation trials, actual milk production was determined using a portable milking machine following a 12-h separation from calves. During late gestation, multiparous cows consumed 24% more (P = 0.01) forage DM (kg/d) than primiparous cows; however, parity class did not influence forage intake when intake was expressed relative to BW. Furthermore, MEPD did not influence forage intake during late gestation. During early lactation, multiparous cows produced 66% more (P < 0.001) milk than primiparous cows, and high MEPD tended (P = 0.10) to produce more milk than low MEPD. Multiparous cows consumed 19% more (P < 0.0001) forage DM than did primiparous cows when expressed on an absolute basis, but not when expressed on a BW basis. High-MEPD cows consumed 8% more (P < 0.05) forage DM than did low-MEPD cows. During late lactation, multiparous cows produced 84% more milk than primiparous cows, although MEPD did not influence (P = 0.40) milk yield. In addition, multiparous cows consumed 17% more (P < 0.01) forage DM per day than primiparous cows, but when intake was expressed relative to BW, neither parity nor MEPD influenced forage DMI during late lactation. Milk yield and BW explained significant proportions of the variation in forage DMI during early and late lactation. Each kilogram increase in milk yield was associated with a 0.33- and 0.37-kg increase in forage DMI for early and late lactation, respectively. Results suggest that multiand primiparous cows consume similar amounts of low-quality forage DM, expressed per unit of BW, during late gestation and lactation. Selecting beef cows for increased genetic merit for milk production increases forage DMI during early lactation.     

Humoral immunity in the ewe. 2. The effect of pregnancy on the primary and secondary antibody response to protein antigen

This study examines the effect of pregnancy on the quantity and isotype of antibody in ewes immunised with a novel primary antigen. The primary and secondary antibody levels to bovine serum albumin (BSA) in alum adjuvant, were compared between non-pregnant ewes and ewes immunised at different stages of pregnancy. Anti-BSA isotype specific responses were measured using an indirect ELISA. Results show the levels of immunoglobulin M (IgM) increased and persisted in response to BSA during pregnancy (P less than 0.05). Secondary immunoglobulin G1 (IgG1) titres were significantly impaired in late pregnancy and during lactation (P less than 0.05). The lower levels of immunoglobulin G2 (IgG2) were unaffected by pregnancy under these experimental conditions. Ewes were also immunised with BSA in alum adjuvant for their primary inoculum and BSA in different adjuvants for the secondary inoculation. Primary IgM persisted at higher levels during pregnancy compared with the response in non-pregnant ewes (P less than 0.05). Following the secondary injection, lower levels of anti-BSA specific IgM, IgG1 and IgG2 antibodies were produced in late pregnancy and during lactation compared with the levels in non-pregnant control ewes (P less than 0.05). Alterations in regulatory T-cell function or effector B-cell activity would most readily explain the qualitative changes in antibody titre observed following primary injection during pregnancy. The results also suggest an associated impairment of immunological memory following primary immunisation during pregnancy.     

Changes in abdominal dimensions during late gestation and early lactation in Holstein-Friesian heifers and cows and their relationship to left displaced abomasum

The changes in abdominal dimensions and contour during late gestation and early lactation were investigated in 44 Holstein-Friesian cattle, 20 normal heifers and 17 normal cows, and seven cows that had a left displaced abomasum (LDA) surgically corrected by a right flank omentopexy in a previous lactation. Abdominal measurements were made eight times during the six months spanning the last trimester of pregnancy and the first three months of lactation, they included the circumference of the thorax and abdomen, the depth and width of the abdomen, the vertical distance between the ventral abdomen and the descending duodenum, the height at the withers, and the length of the trunk. There were significant changes in these dimensions during the last trimester of pregnancy, immediately after parturition and during the first three months of lactation. The depth of the abdomen and the vertical distance between the ventral abdomen and the descending duodenum were greater in the cows with a previous history of LDA than in those without.     

Serum paraoxonase activity and lipid parameters in the early postpartum period of dairy cows

The effect of early lactation on serum paraoxonase activity was studied on 21 postpartum dairy cows and 19 non-pregnant late lactating dairy cows. A significant decrease of the paraoxonase activity was found in the early postpartum period compared to the late non-pregnant lactation. The serum triglyceride, cholesterol and LDL-cholesterol concentration were also markedly reduced during the postpartum period, while the serum HDL-cholesterol concentration showed no significant change. The results indicate that lower serum paraoxonase activity is associated with lipid metabolic disorders in the early postpartum period. A decreased serum paraoxonase activity may lead to the reduction of the antioxidative capacity and antioxidative protection during the early postpartum period.     

The influence of late pregnancy and lactation on bone metabolism in mares

Pregnancy and lactation are periods of significant influence on bone metabolism that has not been investigated in equines. To examine the influence of late pregnancy and lactation on bone metabolism in mares, the changes in the blood serum/plasma total calcium (Ca), inorganic phosphates (Pi), pyridinoline (Pyd) and 17β-estradiol (E2) concentration and the bone alkaline phosphatase (BAP) activity were investigated. The samples were taken from 11 mares on 60 ± 10 and 20 ± 10 days before foaling, and 20 ± 10 and 60 ± 10 days after foaling. The concentration/activity of Ca, Pi, Pyd and BAP increased significantly in early lactation, but the Pyd than decreased in the 4th period. A significant correlation was observed between the E2 and bone metabolism parameters. The results indicate low maintenance of normocalcaemia with reduced bone synthesis in late pregnancy and prove the role of estradiol in bone metabolism in mares during pregnancy and lactation.     

Feeding-unrelated factors influencing the plasma leptin level in ruminants

The triglyceride content of lipid depots associated with the current feeding level is the primary determinant of leptin gene expression and the circulating leptin level. In laboratory rodents and primates the plasma leptin is influenced also by the age, gender and physiological status (puberty, pregnancy, lactation, postpartum period), and by the health condition such as sepsis due to Gram-negative (GN) bacteria. Some pathologic conditions with intensive cytokine release evoke an increase in plasma leptin, which is thought to depress the subsequent feed intake. However, the effect of these secondary factors may be species-dependent, with still unknown clinical relevance in ruminants. In our ovine and bovine models plasma leptin increased after castration and dexamethasone treatment, decreased after experimental administration of synthetic androgens in castrated rams, but remained unchanged throughout the ovarian cycle and after ovariectomy. The circulating leptin level increased temporarily during synthetic progestin (fluorogestone) treatment in ewes, but similar changes were not seen in progesterone-supplemented ewes and norgestomet-treated cows. In a second trial on dairy cows we wanted to study whether elevated plasma leptin levels are induced by experimental endotoxin mastitis, or by natural outbreak of GN mastitis and puerperal metritis. Experimental endotoxin mastitis resulted in some-hour elevation in cortisol and insulin, with a simultaneous decrease in IGF-I and thyroid hormones. In the first 14 days of lactation GN mastitis induced the same endocrine alterations as the experimental endotoxin challenge, but in natural cases these changes varied within a wider range, and were more protracted and robust. Cows with puerperal metritis had more obvious catabolic changes in the early weeks of lactation, than their healthy counterparts. However, both mastitis and puerperal metritis failed to increase the circulating leptin level, showing that in cows the plasma leptin is not responsible for the anorexia associated with these inflammatory diseases.     

Maternal leptin is elevated during pregnancy in sheep

Maternal plasma leptin is elevated during pregnancy in several species, but it is unclear to what extent this elevation reflects changes in adiposity or energy balance. Therefore, Karakul ewes (n = 8) were fed to minimize changes in maternal energy status over the pregnancy-lactation cycle. They were studied 20-40 d before breeding and during mid pregnancy (d 50-60 post coitus [PC]), late pregnancy (d 125-135 PC) and early lactation (d 15-22 post partum). Consistent with the maintenance of near energy equilibrium in nongravid maternal tissues, maternal body weight was increased only during late pregnancy when the weight of the conceptus became significant and plasma concentrations of insulin, NEFA and glucose did not vary with physiological state. In contrast, maternal plasma leptin concentration rose from 5.3 to 9.5 ng/mL between prebreeding and mid pregnancy and then declined progressively through late pregnancy and early lactation. Leptin gene expression increased 2.3 fold in maternal white adipose tissue (WAT) from prebreeding to mid pregnancy and declined to prebreeding levels during early lactation. To determine whether tissue response to insulin was involved in this effect, insulin tolerance tests were performed. The maternal plasma glucose response declined from prebreeding to early lactation, but was not correlated with either plasma leptin concentration or WAT leptin mRNA abundance. In conclusion, pregnancy causes an increase in the synthesis of leptin in sheep. This stimulation does not require increases in adiposity or energy balance and is unrelated to the ability of insulin to promote glucose utilization.     

Negative energy balance increases periprandial ghrelin and growth hormone concentrations in lactating dairy cows

The reported effects of feeding on growth hormone (GH) secretion in ruminants have been inconsistent, and are likely influenced by energy status of animals. High-producing dairy cows in early lactation and late lactation were used to assess the effects of energy balance on temporal variation of plasma metabolites and hormones. Cows were fed a single diet once daily, and feed was withdrawn for 90 min prior to feeding. Beginning at the time of feed withdrawal, plasma samples were collected via jugular catheters hourly for 24h. Concentrations of non-esterified fatty acids and GH were measured for all samples, while insulin, glucose, and acylated (active) ghrelin were quantified for four sample times around feeding. As expected, calculated energy balance was significantly lower in early lactation than late lactation cows (-43.5 MJ retained/day versus 7.2 MJ retained/day). Following the primary meal of the day, a GH surge was observed in early lactation but not in late lactation cows. This difference was not explained by temporal patterns in non-esterified fatty acid, insulin, or glucose concentrations. However, a preprandial ghrelin surge was observed in early lactation only, suggesting that ghrelin was responsible for the prandial GH surge in this group. Results of a stepwise regression statistical analysis showed that both preprandial ghrelin concentration and energy balance were significant predictors of prandial GH increase over baseline. Adaptations to negative energy balance in lactating dairy cattle likely include enhanced ghrelin secretion and greater GH response to ghrelin.     

Use of test day milk fat and milk protein to detect subclinical ketosis in dairy cattle in Ontario.

Serum beta-hydroxybutyrate (BHB) levels were determined for 1333 dairy cows in various stages of lactation and parity on 93 dairy farms in Ontario. The data were collected in a cross-sectional manner, as part of the 1992 Ontario Dairy Monitoring and Analysis Program. The median serum BHB was 536 mumol/L for all cows, with a range of 0 to 5801 mumol/L. When subclinical ketosis was defined as a serum BHB level of 1200 mumol/L or higher, the prevalence of ketosis for cows in early lactation (< 65 days in milk (DIM)) was 14.1%. Prevalences for mid lactation (65-149 DIM), late lactation (> 149 DIM), and dry cows were 5.3%, 3.2%, and 1.6%, respectively. The mean serum BHB was significantly higher in the early group compared with each of the other 3 groups (P < 0.05). There was a trend of increasing prevalence with increasing parity across all stages of lactation. Only the difference between the parity-1 group and the parity-4 and greater group was statistically significant (P < 0.05). Both test-day fat percent and test-day protein percent were significantly associated with subclinical ketosis. However, test-day fat percent and test-day protein percent, used alone or in combination, were not useful screening tests for identifying cows with subclinical ketosis.     

Copper oxide needles administered during early pregnancy improves the copper status of ewes and their lambs

AIM: To determine the effect of copper oxide (CuO) needles administered orally to ewes in early pregnancy on the copper (Cu) status of ewes throughout gestation and lactation, and of their lambs from birth to weaning. METHODS: In mid-April, after mating, 12 twin-bearing ewes were given an oral capsule containing 5 g CuO needles while 12 others served as untreated controls. Changes in Cu status were monitored by determining serum and liver Cu concentrations on Days 1, 62, 117, 153, 185 and 216 in the ewes, and at 1, 36, 68 and 99 days of age for lambs. Pasture herbage samples were collected at about 60-day intervals for Cu, molybdenum (Mo), iron (Fe) and sulphur (S) determinations. RESULTS: Copper status of the ewe flock was adequate, as initial mean serum and liver Cu concentrations were 15 micromol/L and 1,060 micromol/kg fresh tissue, respectively. The CuO needles did not affect serum Cu concentrations of the ewes or their lambs. Mean serum Cu concentration of all lambs at birth was about half that of ewes (8 vs 17 micromol/L), regardless of Cu supplementation, and not until at least 68 days of age was it similar to the dams'. Liver Cu concentrations of lambs at birth were also lower than that of the ewes (380 vs 640 micromol/kg fresh tissue among the controls), but changed little over time. CuO treatment increased liver Cu concentration in ewes for at least 185 days and in lambs for 36 days (p<0.05). Among untreated ewes, there was a seasonal decline in mean liver Cu concentrations, which were highest in autumn and lowest in early spring (1,060 vs 370 micromol/kg fresh tissue). The mean pasture mineral concentrations were Cu 5.7, Mo 0.48, Fe 194 and S 2,900 mg/kg dry matter (DM). CONCLUSIONS: CuO needles administered to ewes in early pregnancy increased their Cu status through gestation and early lactation, and the Cu status of their lambs for 36 days from birth. Serum Cu concentration was not affected by treatment but a marked rise was observed in all lambs between birth and 10 weeks of age. CLINICAL RELEVANCE: Copper deficiency in young lambs may be conveniently and effectively prevented by treating ewes with CuO needles during early pregnancy. The serum Cu concentration in lambs <8 weeks old may not reflect the Cu status of the flock.     

Oxidative status during late pregnancy and early lactation in dairy cows

In the last few years, the detection of free radical damage and the body's defences against it have become increasingly important in clinical medicine as a complementary tool in the evaluation of metabolic status. The aim of this study was to evaluate, under field conditions, the anti-oxidant status of healthy cows during late pregnancy and lactation onset using two parameters: (1) plasma levels of malondialdehyde (MDA), a degradation product of lipid peroxidation, and (2) total antioxidant status (TAS). Results were compared with those obtained in another group of cows with lesser metabolic demands. We also investigated possible relationships between antioxidant status markers and other relevant blood parameters. Our results confirmed the characteristic metabolic changes associated with late pregnancy and early lactation. MDA and TAS provided an accurate reflection of the internal physiological status of the animal. The data indicated increased lipid peroxidation around parturition, but with wide individual variations that may be attributable not only to the physiological stage but also to unknown factors that will have to be further considered in future studies.     

Acute-phase proteins,cortisol and haematological parameters in ewes during the periparturient period

Numerous subclinical diseases in sheep occur in the periparturient period and involve inflammatory processes; therefore, determining markers, such as acute-phase proteins (APPs), can allow an early diagnosis. Therefore, the objective of the present study was to assess changes in the plasma concentration of APPs and cortisol in clinically healthy ewes in the periparturient period for use in future studies. At the same time, haematological parameters were monitored. We showed that plasma APPs and cortisol concentrations were significantly higher in pregnant ewes than before insemination. A gradual increase in the SAA concentration was observed from the 14th day before to the day of parturition, while Hp was reduced from 2 weeks before up to 2 weeks after delivery. A significant increase in the Fb concentration was detected from the 14th day before to the 1st week after delivery. The cortisol concentration did not undergo significant changes in the periparturient period. We found an increase in the SAA and Fb concentrations and decrease in Hp in the periparturient period. The direction of the change in APPs of healthy ewes in the current study may be related to their distinct regulatory mechanisms during pregnancy. The APPs are usually altered during infection, inflammation, neoplasia, stress and trauma; therefore, knowing their reference values could help lead to an early diagnosis of subclinical forms of some diseases and pregnancy complications in ewes. The haematological analysis showed that ewes in late pregnancy and postpartum compared to dry period were under metabolic stress related to pregnancy and lactation.