Dynamics of basic hematologic values in ewes during the course of a year

Basal hematological values were studied in ten primiparous ewes of Merino breed at 15 time intervals in the period from birth to the last decade of the next gravidity. The mean erythrocyte counts ranged from 6.5 to 10.3 T . l-1, hemoglobin content from 101.3 to 121.3 g per l, hematocrit value from 0.32 to 0.37 1 per l, mean corpuscular hemoglobin concentration from 29.97 to 34.22 g per dl, mean corpuscular hemoglobin from 11.17 to 16.61 pg, corpuscular volume from 35.03 to 55.37 fl. The mean leucocyte counts were from 4.98 to 9.93 G . l-1, with 25.8 to 60.5% neutrophil granulocytes with segmented nuclei, 0.1 to 2.6% neutrophil granulocytes with rodlike nuclei, 0.8 to 8.7% eosinophil granulocytes, 0.0 to 0.33% basophil granulocytes, 30.3 to 71.2% lymphocytes and 0.4 to 4.5% monocytes. The quality of red blood component was not negatively influenced by a high degree of gravidity. In the time of parturition, neutrophil granulocytes highly dominated over the other types of white blood cells; the counts normalized since the seventh day post partum. Although statistically significant differences were calculated for some time intervals, the values were within the physiological limits.     

The variations of white blood cell count in Lipizzan horses

Total and differential leucocyte counts (lymphocytes, neutrophils, monocytes, eosinophils and basophils) were measured in 140 stallions, 101 mares and 25 foals of Lipizzan breed. The values fell in the normal ranges for warm-blooded horses. Differences between mares and stallions were not significant with the exception of foals, having higher white blood cell, neutrophil, lymphocyte, monocyte and basophil values in females than in males. Foals exhibited an age-related increase of total leucocyte count during the first 4 months of life, accompanied by a decrease in neutrophil and increase in lymphocyte and eosinophil counts. In mares and stallions, the total number of leucocytes, lymphocytes, monocytes and basophils significantly decreased but the number of neutrophils and eosinophils remained almost unchanged with age gain.     

Acute phase response of sheep: changes in the concentrations of ceruloplasmin, fibrinogen, haptoglobin and the major blood cell types associated with pulmonary damage

The concentrations of plasma ceruloplasmin, plasma fibrinogen, serum haptoglobin and the major cell types in blood together with liveweight changes were monitored during the acute phase response in sheep. Five control sheep, five sheep that underwent sham bronchial obstruction, and five sheep that developed pneumonia after bronchial obstruction were examined. Blood samples were taken and liveweights were recorded from four to six days before until 14 days after the surgical operations (sham and bronchial obstruction). The operations led to an acute phase response in the sheep and the development of pneumonia increased and sustained the response or led to a secondary response. Statistically significant changes observed in the blood of the sheep during the acute phase response included increased concentrations of plasma ceruloplasmin and plasma fibrinogen, depression of erythrocyte numbers and elevation of neutrophil numbers (means on day of maximum change as percentage of pretreatment values; 250 per cent, 400 per cent, 80 per cent and 200 per cent, respectively). Serum haptoglobin showed a pronounced and significant increase in concentration (over 6000 per cent of pretreatment values in some sheep). All three groups of sheep showed significant depression of liveweight after overnight confinement in the surgery but this was sustained for the period of the experiment only in the bronchial obstruction group. The results indicated that measurement of the concentrations of the three plasma proteins may be more useful in the diagnosis of tissue injury and infectious disease than the number of circulating neutrophils in sheep.     

The effect of excessive artificial UV radiation on the measurement of blood parameters and phagocytosis in calves

5 calves of an age of 33 days were exposed to UV-light (280-320 nm) for a time of 12 hours. The mean dose of radiation was 179 x 10(-10) J/h x m-2. The results show slight influences of overdosed radiation on hemoglobin content of the blood, from 105.1 g/l to 102.6 g/l. The mean content of hemoglobin in erythrocytes decreased: 364 g/l to 347 g/l. The total leucocytes decreased from 7.74 x 10(9)/1 to 7.08 x 10(9)/1 after exposition of 5 hours. The exposition increased lymphocytes (55.6% to 66.0%) and decreased neutrophils (43.6% to 33.8%). The relationship of lymphocytes to neutrophils extended even after radiation time of only 5 hours from 1.45 to 2.04. The phagocytotic activity increased after 5 hours of exposition. To the end of exposition (60 hours after observation) a decrease was observed. A correlation between doses of radiation and hematological changes was found after 12 hours of radiation in lymphocyte counts (r = 0.878) and neutrophil counts (r = -0.824) as well as in the relation of lymphocytes to neutrophils counts (r = 0.941) and in the index of phagocytosis (r = 0.804).     

Effect of subcutaneous injection of ginseng on cows with subclinical Staphylococcus aureus mastitis

Cows with subclinical mastitis caused by Staphylococcus aureus were subjected to subcutaneous injections with either an extract from the root of Panax ginseng CA Meyer at a dose of 8 mg/kg body weight per day for 6 days, or with saline as a control. The injection areas were checked for adverse reactions. The daily milk production was measured before and after treatment. Blood was collected for total and differential leucocyte counts, identification of lymphocyte subpopulations using flow cytometry, lymphocyte proliferation test, and neutrophil phagocytosis and oxidative burst assay. Quarter milk samples were collected for bacteriological analysis and somatic cell counts (SCC). After the end of treatment, the numbers of S. aureus-infected quarters and milk SCC tended to decrease in ginseng-treated cows. Phagocytosis and oxidative burst activity of blood neutrophils were significantly increased 1 week after ginseng treatment, but the proliferative response of blood lymphocytes did not change significantly. The number of monocytes in ginseng-injected cows was significantly higher 1 week post-treatment than pre-treatment, and the number of lymphocytes was significantly higher than pre-infusion at 2 and 3 weeks after ginseng treatment. Similar changes were not observed in the control group. The present findings indicate that ginseng treatment can activate the innate immunity of cows and may contribute to the cow's recovery from mastitis. It is therefore suggested that ginseng has a potential as a stimulator of the immune system of dairy cows.     

Ostertagia ostertagi infection in the calf: effects of a trickle challenge on appetite, digestibility, rate of passage of digesta and liveweight gain

The effects of a trickle challenge with the equivalent of 10,000 infective Ostertagia ostertagi larvae per day on appetite, digestibility, rate of passage of digesta and liveweight gain were investigated in 12 calves assigned to infected, pair-fed control and ad libitum-fed control groups. Digestibility of cellulose, nitrogen, organic matter and dry matter was determined using insoluble acid detergent fibre as a marker on two occasions during the study: (i) Between days 31 and 38, when abomasal dysfunction was greatest; and (ii) between days 52 and 58, beginning approximately one week after anthelmintic treatment (day 46). Rate of passage of digesta was measured using chromium mordanted hay, fed to each calf after each digestibility study period. Voluntary feed intake of the infected group was significantly reduced from day 37 with the greatest depression (77 per cent) occurring just before anthelmintic treatment. The drop in appetite was responsible for nearly 73 per cent of the difference in liveweight gain between the infected and ad libitum fed control groups. The apparent digestibility coefficient of nitrogen was significantly depressed (22 per cent) in the infected group though was restored to control levels by anthelmintic treatment. The rate of passage of digesta was significantly reduced in both pair-fed control (50 per cent) and infected (74 per cent) groups. Anthelmintic treatment increased the latter though only to pair-fed control group levels. It is suggested that the marked hypergastrinaemia seen in the infected calves may have been in part responsible for the decreased rate of passage of digesta and in turn for the drop in appetite.     

Ostertagia ostertagi infection in the calf: effects of a trickle challenge on appetite, digestibility, rate of passage of digesta and liveweight gain

The effects of a trickle challenge with the equivalent of 10,000 infective Ostertagia ostertagi larvae per day on appetite, digestibility, rate of passage of digesta and liveweight gain were investigated in 12 calves assigned to infected, pair-fed control and ad libitum-fed control groups. Digestibility of cellulose, nitrogen, organic matter and dry matter was determined using insoluble acid detergent fibre as a marker on two occasions during the study: (i) Between days 31 and 38, when abomasal dysfunction was greatest; and (ii) between days 52 and 58, beginning approximately one week after anthelmintic treatment (day 46). Rate of passage of digesta was measured using chromium mordanted hay, fed to each calf after each digestibility study period. Voluntary feed intake of the infected group was significantly reduced from day 37 with the greatest depression (77 per cent) occurring just before anthelmintic treatment. The drop in appetite was responsible for nearly 73 per cent of the difference in liveweight gain between the infected and ad libitum fed control groups. The apparent digestibility coefficient of nitrogen was significantly depressed (22 per cent) in the infected group though was restored to control levels by anthelmintic treatment. The rate of passage of digesta was significantly reduced in both pair-fed control (50 per cent) and infected (74 per cent) groups. Anthelmintic treatment increased the latter though only to pair-fed control group levels. It is suggested that the marked hypergastrinaemia seen in the infected calves may have been in part responsible for the decreased rate of passage of digesta and in turn for the drop in appetite.     

Biologic quality of colostrum and calves from dairy cows injected with zinc during pregnancy]

The effects of an administration of the Zindep inj. preparation (Biotika) were evaluated in pregnant dairy cows as exerted on specific weight, total protein (TP) content, total immunoglobulin (IgC) and albumin (ALB) contents in colostrum. These parameters were also followed: calf's health, live weight, leucocyte (Lc) counts, T-lymphocyte (T-Ly) counts, contents of TPs, IgCs and ALBs in the blood serum of calves. Zinc concentrations were determined in colostrum, milk and calf blood serum. Our observations included 16 dairy cows in the seventh month of pregnancy in the second lactation and their calves in the winter feeding season. Eight experimental dairy cows were treated with the Zindep preparation in form of an injection to the neck muscles at a dose of 3 mg Zn/kg live weight in the mid-seventh month of pregnancy. Blood samples were taken from v. jugularis from all calves before their first drinking, on days 5, 15 and 30 of age. Colostrum, and/or milk samples were obtained by drawing of the colostrum or milk from the udder quarters within 60 minutes after parturition, on days 5 and 15 of lactation. Zn levels at birth were 16.48 +/- 2.67 mumol/l in experimental calves and 13.84 +/- 3.19 mumol/l in control calves. Zincaemia decreased slightly in both groups on days 5 and 15 of age, but it was insignificantly higher in calves coming from Zindep-treated dairy cows. Zn levels in the blood serum on the 30th day of age were 18.45 +/- 2.44 mumol/l in experimental animals and 15.73 +/- 3.11 mumol/l in control animals. Zn content in the colostrum of experimental cows was 2.40 +/- 0.42 mg/l and in the control it was 1088 +/- 0.52 mg/l (P < 0.05). On day 5 of lactation, Zn amounts in the milk of experimental dairy cows decreased to 0.95 +/- 0.12 mg/l and to 0.76 +/- 0.10 mg/l in the control (P < 0.01). Zn levels in the milk of experimental cows on day 15 of lactation were 0.95 +/- 0.13 mg/l and in the milk of control group they were 0.82 +/- 0.14 mg/l. Colostrum specific weight from zinc-treated cows was 1,067.86 +/- 0.75 g/cm3 and 1,056.8 +/- 13.53 g/cm3 in the control. TP and IgC concentrations were 137.81 +/- 38.11 g/l and 110.13 +/- 29.91 U ZST, respectively, in the colostrum of experimental group, and 105.98 +/- 32.02 g/l and 85.53 +/- 25.42 U ZST, resp., in control animals.(ABSTRACT TRUNCATED AT 400 WORDS)     

Effect of clinoptilolite on serum biochemical and haematological characters of broiler chickens during aflatoxicosis

Clinoptilolite (CLI, a natural zeolite) incorporated into the diet at 1.5 and 2.5 per cent were evaluated for their ability to reduce the deleterious effects of 2.5 mg total aflatoxin (AF) kg(-1)diet on broiler chickens from 1 to 21 days of age. In total 360 broiler chicks were divided into six equal treatment groups (control, AF, CLI (1.5 per cent), AF plus CLI (1.5 per cent), CLI (2.5 per cent) and AF plus CLI (2.5 per cent)). When compared with the controls, AF treatment significantly decreased serum total protein, albumin, inorganic phosphorus, uric acid, total cholesterol and the values of haematocrit, red blood cell counts, mean corpuscular volume, haemoglobin, thrombocyte counts, percentage of monocyte counts; increased values of white blood cell and heterophil counts. The addition of CLI (1.5 per cent) and CLI (2.5 per cent) to the AF -containing diet reduced the adverse effects of AF and should be helpful in a solution to the aflatoxicosis problem in poultry.     

A model for study of lungworm (Dictyocaulus sp.) and gastrointestinal nematode infection in young red deer (Cervus elaphus)

A model of sub-clinical parasitism in young red deer, using concurrent trickle infections of lungworm (Dictyocaulus sp.) and mixed gastro-intestinal (GI) nematodes of deer-origin was evaluated. 20 parasite-free deer calves were artificially reared indoors from 4 days of age. A further five calves were naturally reared on pasture with their dams, treated with anthelmintic and brought indoors at 3-4 months. At 4-4.5 months of age they were individually housed and allocated to five groups (n=5). Groups were dosed 3 x per week, for 9 weeks with 0, 100 and 500, 200 and 1000 (2 groups), 400 and 2000 infective larvae of lungworm and mixed GI nematodes, respectively, cultured from deer faeces. Liveweight and voluntary feed intake measurements and faecal and blood samples were taken weekly. In the fourth week following cessation of trickle infection, deer were euthanased and lung and GI nematodes recovered. Both lungworm and GI nematode infections became patent at Week 4 of infection. Maximum group arithmetic mean faecal egg counts were 100-190 epg. Maximum group arithmetic mean faecal lungworm larval counts were 58-123 lpg. Group arithmetic mean nematode counts at slaughter ranged from 439-806 for GI nematodes and 31-73 for lungworm, respectively. Despite low nematode counts, reduced liveweight gain, voluntary feed intake and serum albumin concentration, elevated serum pepsinogen, gastrin and globulin concentrations and elevated peripheral eosinophil counts and slight haemoconcentration, but no clinical signs, were observed. The reduction in liveweight gain was related to the reduction in voluntary feed intake (r2=0.83; p<0.088). Naturally-reared deer had similar liveweight gains, voluntary feed intake and nematode counts to artificially-reared deer. Thus, methods of infection to produce concurrent sub-clinical lungworm and GI nematode burdens for study of sub-clinical parasitism in young deer have been defined.     

The effect of clover silage treated with acrylic acid on selected indicators of metabolism in cows around the time of parturition and the status of their calves]

A trial was conducted with 16 cows divided into control and test group (eight cows in either); since day 57.6 +/- 21.1 before parturition, test cows were given feed rations for 107 days which contained 16.0 kg clover-grass silage a day, treated with 3 l acrylic acid per t ensiled matter. Control group of cows was administered feed rations containing silage treated with 4 l formic acid per 1 t ensiled matter from day 55.5 +/- 21.9. In the blood (plasma) of test cows the alkaline phosphatase activity was increasing gradually, in the time after parturition a tendency of lower glucose (P 0.05 to 0.01), thyroxine and triiodothyronine concentrations was observed, and the phagocytal activity of leucocytes and its index decreased. The levels of ketone bodies and aspartate aminotransferase activity were found to be higher. In this period in urine the pH value and net acid-base output were lower, while the inorganic phosphorus concentration was higher. No difference were observed in colostrum density, liveweight of born calves and in the target metabolic parameters in the blood (plasma) of calves. In the 30-day period of investigation the cows of test group gave an average daily milk yield lower by 1.5 l (in comparison with control cows). The residues of acrylic acid (method sensitivity of 1.0 mg acrylic acid in 1 l sample) were not detected in their colostrum and milk.     

Effects of the combination of DL-alpha-difluoromethylornithine and diminazene aceturate in Trypanosoma congolense infection of dogs

The therapeutic activity of a combination of difluoromethylornithine (DFMO) with diminazene aceturate was investigated in mongrel dogs experimentally infected with Trypanosoma congolense. The criteria used in the assessment of the trypanocidal effect of the therapy include the examination of the blood for parasites, as well as clinical and haematological changes at intervals following treatment. Diminazene aceturate and DFMO alone and in combination produced intermittent aparasitaemia in the dogs. Although relapse infection occurred with all three treatment regimes, the drug combination gave the best result. The packed red cell volume, haemoglobin concentrations and red blood cell values decreased significantly following parasite inoculation but increased after treatment. The total leucocyte counts decreased in all the infected dogs but improved with treatment, and the differential leucocyte counts indicated neutropenia in all the infected animals prior to treatment.     

General adaptation syndrome (Selye) in the calf. 5. Effect of increased glucocorticosteroid values on the phagocytosis activity of luekocytes, the function of RHS and the morphology of lymphatic organs]

Studies were conducted with the view to elucidating the correlations between increased glucocorticosteroid levels in the blood and the defense potential of calf organism against infectious diseases. The test animals were exposed to several substances (ACTH, cortisol, colibacteria, coliendotoxin), and even one to two days of increased 11-OHKS values were followed by marked decline in phagocytosis activity of leucocytes. In addition, RHS function was considerably reduced, after ten to thirteen days of application had elapsed, since at that point the disappearance of intravenously applied bacteria from circulating blood of test animals took place at rates which were much lower than those recorded from untreated calves. Differentiated length of stress or action (four to thirteen days) was followed by conspicuous changes in the lymphatic tissue of calf organism, with severe involution of thymus and follicular atrophy of intestine-associated lymphatic tissue having been the major findings. The results seem to suggest that rise in adrenocortical hormone level under stress may reduce potential organic defense to infection.     

短花针茅草原五个载畜率水平绵羊活重变化规律

在内蒙古高原短花针茅荒漠草原采用5个不同载畜率水平进行的绵羊放牧试验结果表明,绵羊活重均以10月份为最大,中等载畜率有利于绵羊生产;随着载畜率增大,单位面积的绵羊增重逐渐增加,单个绵羊的增重逐渐减少,两者的交点为绵羊生产的适宜载畜率,即每半年 2.2只羊/hm2.     

Copper supplementation, velvet antler production and growth of rising 2-year-old red deer stags

AIMS: To investigate whether copper supplementation to rising 2-year-old red deer stags (Cervus elaphus) in winter and/or spring improved velvet antler weight, grade and financial value, and liveweight gain. METHODS: Rising 2-year-old red deer stags (n=142) on a commercial deer farm in Hawke's Bay were allocated to two groups on May 14, 1996. One group received 20 g boluses of copper-oxide wire particles. On August 15 each group was reallocated in a crossover design, each sub-group receiving either the same copper-oxide treatment or no treatment, to produce control, winter-only, winter-plus-spring, and spring-only copper treatment groups. Blood samples were collected for serum ferroxidase measurements from seven deer per group and all deer were weighed at 4-6-week intervals. Dates of antler casting and velvet removal, and velvet antler weight and grade were recorded, and the financial value of velvet calculated. Livers from a sample of deer slaughtered at the end of the trial mid-December were analysed to determine copper content. RESULTS: Supplementation with copper did not significantly alter velvet antler weight, daily velvet antler growth rate, days from casting to removal, grade or value, or stag liveweight gain. Serum ferroxidase concentrations averaged 10.0-23.7 IU/l in control deer. Copper supplementation increased mean serum ferroxidase concentrations by approximately 10 IU/l. Mean liver copper concentration in control deer was 99 micromol/kg and ranged from 194 to 386 micromol/kg in the three treated groups. CONCLUSION: Group mean serum ferroxidase concentrations of 10 IU/l and above are adequate for optimum velvet production and liveweight gain in rising 2-year-old stags.     

Effects of fermented garlic powder supplementation on growth performance, blood profiles and breast meat quality in broilers

The aim of this study was to investigate the effects of dietary supplementation with fermented garlic powder (FGP) on growth performance, blood profiles and breast meat quality in broilers. A total of 500 broilers were randomly allotted to 4 treatments with 5 replications per treatment and 25 chicks per pen. The experiment lasted for 5 weeks and dietary treatments were as follows: 1) CON (basal diet); 2) FGP1 (basal diet + 1 g/kg fermented garlic powder); 3) FGP2 (basal diet + 2 g/kg fermented garlic powder); 4) FGP4 (basal diet + 4 g/kg fermented garlic powder). No effects were observed (P > 0.05) in body weight gain (BWG), feed intake (FI) or feed conversion ratio (FCR) throughout the whole experiment. The white blood cell (WBC) counts, lymphocyte and immunoglobulin G (IgG) was increased (P < 0.05) in response to FGP treatments. Broilers had lower (P < 0.05) total cholesterol, triglyceride, low-density lipoprotein (LDL) cholesterol and cortisol concentrations in blood when they were provided with FGP2 and FGP4 diets. Compared with CON, FGP2 and FGP4 treatments decreased (P < 0.05) TBARS and pH in breast meat. In conclusion, FGP administration had no effect on growth performance but improved immunity and meat quality as well as decreased cholesterol and cortisol in blood.     

Genetic Variation in Bovine Neutrophil Sensitivity to Glucocorticoid Challenge

Blood neutrophils use CD62L and CD18 adhesion molecules to contact and migrate rapidly through blood vessels in defense against infections in underlying tissues. Previous work showed that glucocorticoid hormones repress expression of CD62L and CD18, causing neutrophilia and increased mastitis susceptibility in dairy cows. The aim of this study was to determine whether bovine neutrophil sensitivity to glucocorticoids exhibits genetic variability. Test animals included 60 pedigreed Holstein bulls treated on 3 consecutive days with a synthetic glucocorticoid (dexamethasone) and five untreated control bulls. Five indicator traits of neutrophil glucocorticoid sensitivity were monitored, including circulating neutrophil counts and two measures on each of CD62L and CD18 expression. Random regression models with treatment-specific serial correlation were used to estimate genetic and non-genetic sources of variation before, during and after glucocorticoid administration. Significant genetic variation was observed for neutrophil CD18 expression, with longitudinal heritability estimates ranging from 0.10 to 0.54 and influenced by dexamethasone. Significant genetic variation was also observed for blood neutrophil counts (heritability estimates ranging from 0.11 to 0.24) but was not influenced by dexamethasone administration. Estimated genetic correlations between circulating neutrophil counts and various indicators of CD62L and CD18 expression were large and negative (-0.44 to - 0.78). These results imply significant genetic variability and pleiotropic effects for neutrophil traits that are important for stress-induced disease susceptibility in dairy cattle and might be exploited by genetic selection.     

Nephrotoxicity in Goats Caused by Dosing with a Water Extract from the Stems of Narthecium Ossifragum Plants

Seven goats were given a single dose of an aqueous extract derived from 30 g (wet weight) of Narthecium ossifragum per kg liveweight. Their serum creatinine and urea concentrations increased to day 5 but then fell to normal by day 10. Serum magnesium increased to day 4 and decreased to normal by day 9. Their serum calcium concentration was lower than normal on days 4, 5 and 6. Histopathological examination of the kidneys of goats killed or found dead 2, 4, 6, 8, 11 or 16 days after dosing revealed tubular epithelial cell degeneration and necrosis. Regeneration of the tubular epithelium and signs of interstitial fibroplast proliferation and fibrosis could be seen in animals killed on days 8, 11, 16 and 42. No signs of liver damage were observed in 3 goats dosed with the insoluble plant material from 40 g (wet weight) Narthecium ossifragum per kg liveweight. The total dose was divided into three doses, which were given intraruminally within 7 h. The activities of aspartate aminotransferase, -glutamyl-transferase and glutamate dehydrogenase remained within the normal range in all 10 goats after dosing.     

Phenotypical characterization of peripheral blood leucocytes in the newborn calf

The present study was undertaken to establish reference values for the composition of blood leucocyte populations in neonatal calves by differential leucocyte counts and immunophenotyping. Neonatal calves 1 h post partum (p.p.) were found to have a very high absolute number of granulocytes while the number of peripheral blood mononuclear cells was lower than in calves aged 3-9 weeks. The relative numbers of T cell subpopulations were similar in newborn and older calves, but newborn calves had lower percentages of B cells and MHC class II positive cells. Within the first 4 h of life the relative numbers of CD2+, CD6+, and CD8+ T cells declined in colostrum-fed as well as in colostrum-deprived calves. In contrast, the percentage of MHC class II positive cells and monocytes increased from 1 h to 4 h p.p. particularly in colostrum-fed calves. Although there is some evidence for immaturity of lymphocytes in neonatal calves, the immune system of these animals seems to be fully present at birth.     

Effect of liveweight and condition score of ewes at mating, and shearing mid-pregnancy, on birthweights and growth rates of twin lambs to weaning

AIMS: To determine the effects of liveweight and condition score of ewes at mating, and shearing mid-pregnancy, on birthweights and growth rates of twin lambs from birth to the time of weaning, and; to determine whether any effect of condition score is independent of liveweight. METHODS: Romney ewes (n=435) which conceived within a 17-day mating period and successfully gave birth to and reared twin lambs to weaning were used. Ewes were managed during pregnancy so that their total liveweight increased at a level equivalent to the expected growth of the conceptuses. Approximately half of the ewes were shorn 70 days after the mid-point of mating, and the remainder were left unshorn, at which time they had 6-months' wool growth. All lambs were weighed within 12 h of birth and again at weaning. RESULTS: There was a significant linear relationship (R2=0.99) between mean group liveweight and condition score of ewes at mating (difference of 7.3 kg per 1.0 unit condition score). Liveweight of ewes at mating had small but significant (p<0.05) positive effects on both birthweights and growth rates of twin lambs to weaning. Ewes that had condition scores of 3.5-4.0 (scale 0-5) at mating gave birth to significantly (p<0.05) lighter lambs than ewes that had condition scores <3.5. The condition score of ewes at mating was positively associated with growth rates of lambs, although this effect was largely explained by variation in the liveweight of ewes at mating. Twin lambs born to ewes shorn mid-pregnancy were significantly (p<0.05) heavier at birth (by 0.4 kg) and at weaning (p<0.05) than those born to unshorn ewes. The heavier weaning weights of lambs born to ewes shorn mid-pregnancy were due to a heavier birthweights rather than increased growth rate. CONCLUSIONS: Liveweight and condition score of ewes at mating had small positive effects on growth rates to weaning of twin lambs. Shearing mid-pregnancy increased birthweights and weaning weights of twin lambs. To achieve high weaning weights of twin lambs, farmers should ensure ewes attain high liveweights and condition scores at mating and shear mid-pregnancy. It is speculated that the effects of liveweight and condition score of ewes at mating on weaning weights of twin lambs would be greater than those observed in the present study under conditions in which nutrition of the dam is below optimum.