A MUCOSAL DISEASE VIRUS INFECTION OF THE PREGNANT EWE AS A CAUSE OF A BORDER DISEASE-LIKE CONDITION

An experiment was designed to investigate whether a condition in Australian sheep with clinical and pathological similarites to Border Disease was caused by the infection of the pregnant ewe with a Mucosal Disease virus (MDV). Forty ewes, at 58 to 63 days after mating, were inoculated with material from lambs in which all, some or none of the tissues examined contained MDV. The clinical condition was observed only in lambs born to ewes inoculated with MDV-positive material and then only to ewes in the group which had serological evidence of MDV infection. It is concluded that the Border Disease-like condition in Australian sheep is caused by the infection of the pregnant ewe with a Mucosal Disease virus.     

The experimental production of mastitis in ewes as a determinant of the virulence of ovine ureaplasma strains

Seven out of eight ovine ureaplasma strains inoculated into the mammary gland of suckling ewes produced a mastitis. The pattern of infection was single phase in 5 ewes, persisting for 12-41 days, and biphasic in 3 ewes, persisting in 2 of them until weaning at 60 days and 3 months post-infection. Sucking lambs did not become infected in the eye or nasal areas, and did not transfer infection to the control contralateral glands.     

The effects of maedi-visna virus infection on productivity in ewes

A total of five data sets obtained from four separate sheep flocks were used to evaluate the effects of subclinical maedi-visna virus infection (as determined by serological procedures) on productivity in ewes. In general, infection with maedi-visna virus had a detrimental effect on productivity. Infection resulted in a reduction in conception rates, with the odds of an infected ewe conceiving being only approximately 0.67 times those of a non-infected ewe. For ewes which did conceive, there was no detrimental effect of infection on the number of lambs born. The birth weights of lambs born to middle-aged (3–4 years) infected ewes were 3–6% lower than the weights of lambs born to non-infected ewes of the same age. There was very little apparent effect of infection in younger (1–2 years) and older (5 + years) ewes: some factors which may have biased these results are discussed. Lamb weights at 25–50 days of age appeared to be reduced by maedi-visna infection in the ewe but the results were not statistically significant.     

Experimental infection of pregnant ewes with Listeria monocytogenes

Eight 18-month-old ewes were infected orally with Listeria monocytogenes between 77 and 91 days of pregnancy. Only one ewe aborted, 10 days after the first infecting dose, at 94 days of gestation; L monocytogenes was isolated from several sites in both its aborted fetuses. Two days after the first infecting dose all the ewes exhibited mild illness and pyrexia lasting for two to three days but the ewe which aborted was seriously ill until nine to 10 days after aborting. Agglutination tests carried out on 2-mercaptoethanol reduced sera revealed a strong immunological response in all the infected ewes but in the ewe which aborted this response was delayed. Four uninfected ewes which were kept as controls remained healthy throughout the experiment and showed no evidence of 2-mercaptoethanol resistant antibodies to L monocytogenes. Growth retardation lines, occurring at the time of and after experimental infection, were found in the bones of 14 of 17 newborn lambs in both the infected and control groups; in the aborted lambs these lines occurred before the infection.     

Bluetongue virus serotype 20 infection in pregnant Merino sheep

Eleven maiden Merino ewes, free of antibody to bluetongue virus serotype 20 (BTV-20) in agar gel immunodiffusion and serum neutralisation tests, were mated once with a ram. Ten ewes were inoculated with BTV-20 35 to 42 days after service, and one ewe was left as an uninoculated control. One of the inoculated ewes and the control ewe remained uninfected throughout the experiment. Eight of the remaining 9 ewes showed clinical signs ranging from mild to moderate, and the other showed no clinical signs of infection. BTV-20 viraemia was detected in ewes between days 3 and 11 post inoculation, and the serum antibody response was followed. The control ewe and 5 of the 9 infected ewes were pregnant when examined 90 to 97 days after service. Each of these animals produced a normal lamb. There was no evidence of abortion in the remaining 5 ewes, and no transplacental transfer of virus was detected in the lambs of the 5 infected ewes. At necropsy, 46 days after the birth of the last lamb, no gross or microscopic lesions were observed in either the ewes or lambs.     

Successful fostering of orphan lambs by nonpregnant ewes induced to lactate using exogenous hormone treatment

Six nonpregnant ewes were induced to lactate by an exogenous hormone treatment lasting 6 weeks. At the end of the treatment one alien lamb was adopted by each ewe. Each ewe was initially indifferent to the alien lamb and required only mild restraint to allow the lambs to suck successfully. Maternal interest subsequently increased and strong ewe-lamb bonding was evident by 80 minutes (n=l), 10 hours (n=4) or 24 hours (n=l) in different cases. The lambs required supplementary milk for 4–6 days while milk production by the ewes increased to adequate levels. Thereafter they were reared entirely by the ewes. Another four nonpregnant ewes were induced to lactate by a similar hormone treatment and were then hand-milked thrice daily for 2-3 weeks. One alien lamb was then introduced to each ewe. All four ewes were aggressive towards the lambs which were removed after 10–30 minutes. The ewes were then injected subcu- taneously with 5 mg of oestradiol-17β and were placed in fostering stocks. After a further 3–5 hours the lambs were re-introduced. Strong ewe-lamb bonding occurred during the subsequent 10 hours in all cases. All 10 lambs were reared successfully by these ewes until at least 3 months of age, when observations stopped. It was concluded firstly that nonpregnant ewes induced to lactate artificially will adopt and rear orphan lambs successfully, provided that additional milk is given to meet shortfalls during the first 4–6 days; and secondly that a 5 mg injection of oestradiol-17β may facilitate fostering of lambs by ewes in established lactation whether the lactation is induced artificially or not.     

Shedding of Coxiella burnetii in ewes in two pregnancies following an episode of Coxiella abortion in a sheep flock.

Coxiella burnetii infection in pregnant sheep typically causes abortion or the birth of weak lambs. Two C. burnetii-related abortions in a group of 34 pregnant ewes were reported at their first lambing in our research institute. The seroprevalence of C. burnetii infection and bacteria shedding were investigated using an ELISA and PCR, respectively, during the course of two subsequent pregnancies. None of the ewes examined seroconverted from negative to positive at the time of the second and the third parturition and most of the ewes that were seropositive at the abortion episode remained positive throughout the investigation. The two successive pregnancies resulted in the birth of healthy lambs without PCR evidence of Coxiella infection from placenta and vaginal swabs taken postpartum. PCR assay performed on vaginal swabs taken from all animals 1, 5 or 12 days after the second lambing were also negative for Coxiella. However, one ewe that had previously experienced C. burnetii shedding at the first lambing excreted the bacteria in the genital tract after the third parturition. The bacteria could not be detected by PCR in milk and faecal samples taken up to 12 days after both parturitions.     

Successful fostering of orphan lambs by non-pregnant ewes induced to lactate using exogenous hormone treatment

Six nonpregnant ewes were induced to lactate by an exogenous hormone treatment lasting 6 weeks. At the end of the treatment one alien lamb was adopted by each ewe. Each ewe was initially indifferent to the alien lamb and required only mild restraint to allow the lambs to suck successfully. Maternal interest subsequently increased and strong ewe-lamb bonding was evident by 80 minutes (n=1), 10 hours (n=4) or 24 hours (n=1) in different cases. The lambs required supplementary milk for 4-6 days while milk production by the ewes increased to adequate levels. Thereafter they were reared entirely by the ewes. Another four nonpregnant ewes were induced to lactate by a similar hormone treatment and were then hand-milked thrice daily for 23 weeks. One alien lamb was then removed after 10-30 minutes. The ewes were then injected subcutaneously with 5 mg of oestradiol-17beta and were placed in fostering stocks. After a further 3-5 hours the lambs were re-introduced. Strong ewe-lamb bonding occurred during the subsequent 10 hours in all cases. All 10 lambs were reared successfully by these ewes until at least 3 months of age, when observations stopped. It was concluded firstly that nonpregnant ewes induced to lactate artificially will adopt and rear orphan lambs successfully, provided that additional milk is given to meet shortfalls during the first 4-6 days; and secondly that a 5 mg injection of oestradiol-17beta may facilitate fostering of lambs by ewes in established lactation whether the lactation is induced artificially or not.     

Evaluation of ewe and lamb immune response when ewes were supplemented with vitamin E

Fifty-two Targhee twin-bearing ewes were used in a factorial arrangement of treatments to investigate the role of supplemental vitamin E (vit E); 0 (NE) vs 400 IU of vit E x ewe x (-1)d(-1) (E) and parainfluenza type 3 (PI3) vaccination; none (NP) vs PI3 vaccination (P) in immune function. Parainfluenza type 3 vaccination was used to evoke an immune response. Ewes receiving PI3 were vaccinated at 49 and 21 d before the expected lambing date. Ewes receiving vit E were orally dosed daily, 32 to 0 d before lambing. Blood was collected from ewes at the time of the initial PI3 vaccination and 4 h postpartum. Blood was collected from lambs (n = 104) at 3 d postpartum. Ewe and lamb sera were analyzed for anti-PI3 antibody titers, immunoglobulin G (IgG) titers, and vit E concentrations. Colostrum was collected 4 h postpartum and analyzed for IgG. The model for ewe and lamb analysis included the main effects of vit E and PI3, sex (lambs model only), and their interactions. No interactions were detected (P > 0.20) for any ewe or lamb variables. Serum anti-PI3 titers were greater (P < 0.01) in P ewes and their lambs than NP ewes and their lambs. Serum vit E concentrations were greater (P < 0.01) in E ewes and their lambs than NE ewes and their lambs. Colostral IgG titers and serum anti-PI3 titers did not differ (P > 0.20) between E and NE ewes. Serum IgG titers in E ewes and their lambs did not differ (P > 0.15) from IgG titers in NE ewes and their lambs. Lamb anti-PI3 titers did not differ (P = 0.76) between lambs reared by E and NE ewes. These results indicate that, although supplemental vit E to the ewe increased lamb serum vit E concentration, it had no effect on measures used in this study to assess humoral immunity in the ewe or passive immunity to the lamb.     

Comparison of Booroola Merino and Finnsheep: effects on productivity of mates and performance of crossbred lambs

Booroola Merino (BM) and Finnsheep (FS) rams were mated to FS and crossbred (CO) ewes to compare their effects on the productivity of their mates and the performance of their progeny. Effects of breed of ram and the interaction of breed of ram X breed of ewe were no significant for fertility, total number born, number born alive, litter birth weight, or number of lambs weaned by the ewe or in the nursery. Birth weights of FS- and BM-sired lambs were equal, but FS-sired lambs were heavier at weaning and 147 d of age. Compared with BM-sired lambs, survival from birth to weaning of dam-reared lambs was greater for FS-sired lambs produced by CO dams than for FS-sired lambs produced by FS dams. At a constant live weight, FS-sired lambs had a heavier carcass with less external fat thickness than BM-sired lambs. Percentage of ewe lambs reaching puberty was lowest and age at puberty was highest for the BM X CO cross; relatively small differences existed between the other three genotypes for these traits. Ewe lambs sired by BM had a greater ovulation rate than FS-sired ewe lambs. Embryo mortality was greater in BM X CO ewe lambs than in ewe lambs of the other three genotypes; the difference was larger for ewes with three ovulations than for ewes with two ovulations. The net result was that BM X CO ewe lambs averaged slightly fewer lambs born than FS X CO ewes. The BM X FS ewe lambs had larger litters than the FS ewes due to a substantially higher ovulation rate and only a slightly lower overall embryo survival rate. With the exception of ovulation rate and litter size, FS rams produced lambs with a more desirable level of performance than did BM rams.     

Influence of body weight and number of inseminations on fertility of progestogen-treated ewe lambs raised in controlled environments

The influence of body weight at breeding on reproductive response to one and two artificial inseminations (AI) of fresh extended semen was assessed in 195 crossbred ewe lambs selected for early breeding and compared with 159 adult ewes, all housed indoors in a controlled environment. In six trials, ewe lambs and adult ewes in progestogen-induced estrus were inseminated 55 to 57 h after sponge removal. One-half of the lambs and one-fourth of the adults received a second insemination at 60 h. Resultant reproductive performance of both groups indicated no advantage in a double insemination. Overall fertility, litter size and fecundity after one and two inseminations were 33%, 1.7 and .6 for ewe lambs and 68%, 2.4 and 1.6 for adult ewes, respectively. Embryonic mortality after the first 2 wk of pregnancy was estimated at 24% for ewe lambs and 9% for adults. The influence of body weight was analyzed by grouping the ewe lambs according to body weight at breeding. The lambs in group 1 weighed 30 to 35 kg; group 2, 36 to 40 kg; group 3, 41 to 45 kg and group 4, 46 to 50 kg. The proportion of ewes lambing in groups 1, 2, 3 and 4 was 16, 34, 39 and 48%, respectively. Corresponding litter sizes were 1.4, 1.6, 1.8 and 2.0. Fecundity increased (P less than 01) from .2 in group 1 to 1.0 in group 4. The results indicate that even when ewe lambs are bred by AI (eliminating a ram behavioral problem), sheep with heavier body weights produce more lambs per ewe bred.     

Establishment of a maedi-visna-free flock after the purchase of infected sheep

Maedi-visna (MV) infection was detected in a cohort of 68 purchased ewes, one of several groups of sheep introduced to a farm after the previous stock had been culled with suspected foot-and-mouth disease in 2001. Except for short periods totalling six to seven weeks when the sheep co-grazed with 13 ewe lambs and ram lambs, the infected cohort was kept separate from other sheep on the farm over a total of 21 months. During this period two crops of lambs were reared from the infected ewes. All the lambs were fattened and killed, and all ewes were culled after the second crop of lambs had been weaned. Subsequent serological testing of the remaining sheep on the farm confirmed the elimination of MV infection from the flock, leading to its acceptance in the Maedi Visna Accreditation Scheme of the Scottish Agricultural College's Sheep and Goat Health Schemes.     

The incidence of genotypes at codon 171 of the prion protein gene (PRNP) in five breeds of sheep and production traits of ewes associated with those genotypes

Scrapie is one of several transmissible spongiform encephalopathies of livestock. Disease susceptibility is linked to polymorphisms in the normal prion protein gene that encodes the mammalian prion precursor. Codon 171 of this gene is a major determinant of scrapie susceptibility. Selection for arginine (R) at codon 171 is encouraged by the USDA to decrease the incidence of scrapie. Objectives of this study were to determine the frequency of R allele variants at codon 171 in a sample of sheep from five breeds (Columbia, Hampshire, Rambouillet, Suffolk, and Targhee) and western white-faced commercial ewes and to determine whether the R allele is associated with ewe and lamb production traits. Genotyping was performed on 532 ewes and 901 lambs from the University of Wyoming flock, in addition to 820 rams from 52 sheep producers from Wyoming and surrounding areas, using a DNA mismatch assay that discriminated the R allele from others at codon 171. Genotyping was performed by DNA sequencing on 127 rams representing all breeds, except Hampshire from the USDA Sheep Experiment Station at Dubois, ID. The 171R allele was found in all five breeds and in the commercial western white-faced ewes. Genotype frequencies varied (P < 0.001) by breed in ewe and ram populations. Influence of R-allele frequency on ewe lambing records and individual lamb records was analyzed for Columbia (62, 161, 121), Hampshire (89, 193, 162), Rambouillet (87, 179, 133), Suffolk (67, 178, 161), and commercial sheep (227, 463, 324) for numbers of ewes, total number of ewe production records, and individual lamb records, respectively. Suffolk ewes without the R allele (non-R/non-R) gave birth to more (P or= 0.08) by ewe genotype. Lamb birth and weaning weights were not influenced (P >or= 0.12) by lamb genotype in any of the breeds or in the commercial flock. In this population, ultimate lamb production was only influenced by genotype at codon 171 in the Suffolk flock.     

Straightbred comparison of a composite population and the Suffolk breed for performance traits of sheep

A terminal sire Composite population was formed by mating Columbia rams to Hampshire-Suffolk crossbred ewes. Subsequent generations were produced by inter se mating. The objective was to compare Composite sheep to purebred Suffolks for numerous performance traits. Young ewes lambing at 1 yr of age were evaluated separately from mature ewes (2, 3, 4, and 5 yr old) of each population. Composite and Suffolk populations did not differ significantly in components of litter weaning weight per young ewe joined. Mature Composite ewes produced more wool than Suffolk ewes. Fertility of mature ewes did not differ significantly between populations. The greater prolificacy (P less than .01) of mature Suffolk ewes was offset by a lower survival to weaning (P less than .01), particularly for twin-born lambs. Consequently, mature Composite and Suffolk ewes did not differ for number weaned and litter weaning weight per ewe joined. The average birth weight of lambs born to young and mature Composite ewes was greater (P less than .02) than the average birth weight of Suffolk lambs. The average weaning weight of lambs born to young Composite ewes was greater (P less than .05) than that of lambs born to young Suffolk ewes. Breed differences were not detected for preweaning daily gains, weaning weights, and postweaning daily gains of ewe lambs born to mature ewes. Likewise, weights of ewes at 125 d of age and weights of mature ewes at breeding did not differ significantly between breeds.(ABSTRACT TRUNCATED AT 250 WORDS)     

OBSERVATIONS ON SERUM THYROXINE CONCENTRATIONS IN LAMBS AND EWES TO ASSESS IODINE NUTRITION

Thyroxine levels in serum of lambs and ewes were measured to determine their usefulness in assessing iodine nutrition of sheep. Lambs born on properties with no history of goitre had serum thyroxine concentrations more than twice that recorded in their mothers. These high values decreased to a level similar to that in the ewes after 8 weeks. In goitrous lambs younger than 2 weeks old, serum thyroxine concentrations were less than their ewe levels. Lambs born to ewes supplemented with iodine during pregnancy had higher thyroxine levels than lambs of control ewes.
A survey of 80 flocks of ewes in Victoria showed that 40% had a low mean thyroxine concentration (less than 50 nmol/l), but only one of these properties had reported an outbreak of goitre. It is suggested that serum thyroxine levels in newborn lambs may provide a more sensitive indicator of hypothyroidism associated with iodine deficiency than ewe levels.     

Effect of diet and type of pregnancy on plasma metabolic response in sheep and its further effect on lamb performance

This trial evaluated the individual and interactional effects of diet and type of pregnancy (twin or single) on plasma metabolic response in ewes and their lambs from late pre-partum to late post-partum. Thus, a flock of 18 Ile de France breed sheep, consisting of 8 twin-bearing and 10 single-bearing ewes, were allocated to one of two groups according to their diet, either based on ad libitum naturalized pasture hay (NPH) or red clover hay (RCH), from d 45 pre-partum to d 60 post-partum. Plasma samples were collected at different times to determine albumin, cholesterol, total protein and urea, plus glucose and β-hydroxybutyrate (BHB) concentration in ewes. The data was processed using the lme4 package for R, and SPSS Statistics 23.0 for Windows. The results showed that both diet and type of pregnancy influenced the metabolic profile in ewes, showing an inverse relationship between single- and twin-bearing ewes regarding glucose and especially BHB proportions from pre-partum to birth. During post-partum, higher urea concentrations were observed in twin- and single-bearing ewes fed RCH in contrast to those fed NPH, as a result of the higher-quality forage offered to ewes. Regarding lambs, the diet and type of pregnancy influenced the total protein and urea levels, where an inverse relationship at birth and early post-partum between albumin and cholesterol vs. total protein and urea was detected, reflecting a trend (P value between 0.06 and 0.07) to a better performance by groups of single lambs, especially those from single-bearing ewes fed RCH. Finally, under the conditions of this study, the maternal diet and type of pregnancy influenced the plasma metabolic response in ewes and their lambs, affecting the lamb performance especially at birth.

     

The transfer of maternal IgE and other immunoglobulins specific for Trichostrongylus colubriformis larval excretory/secretory product to the neonatal lamb

The transference of immunoglobulins from six New Zealand Romney ewes to their lambs was examined. Immunoglobulin levels were determined in ewe plasma, colostrum and lamb plasma shortly after birth and before the lambs fed, in lamb plasma 2 days after birth, and lamb plasma, ewe plasma and milk 30 days after parturition. Levels of total IgE, and IgE, IgG1, IgG2, IgM, and IgA with specificity for Trichostronglus colubriformis third stage larval secretory/excretory products (TcL3E/S) were determined. Mean levels of total IgE were three times higher in colostrum than in parturient ewe plasma while only trace amounts were detected in milk at 30 days after birth (107.7, 34.3, and 0.2U ml(-1), respectively, differences between means P< or =0.01). Mean total IgE in lamb plasma rose from being undetectable before suckling to levels comparable to those of the ewes by 2 days after birth (21.7U ml(-1)) and then declined to low levels by 30 days (0.4U ml(-1)). Total IgE levels in lamb plasma were significantly correlated with levels in ewe plasma and colostrum (r=0.91, P< or =0.01; r=0.96, P< or =0.003, respectively). The transference of TcL3E/S-specific IgE, IgG1 and IgA was substantial with mean levels of these antibodies in lamb plasma at 2 days comparable to that in parturient ewe plasma (absorbance levels in lamb plasma of 0.283, 0.537, and 0.334, respectively). Proportionally less maternal IgM and IgG2 appeared to be transferred to the lambs (absorbance of 0.112 and 0.081, respectively). Levels of TcL3E/S-specific IgE and IgG1 in lamb plasma at 2 days were significantly correlated with levels in parturient ewe plasma and colostrum (r=0.89 and 0.82, 0.85 and 0.96; all P< or =0.05, respectively). These results indicate that IgE is concentrated in ewe colostrum and that substantial amounts of maternal IgE are transferred to lambs via colostrum. Further, the results suggest that humoral immunity against gastro-intestinal nematode parasites and potentially other parasites in colostrum-fed lambs may approximate that of the ewe. The implications of the transference of humoral immunity through colostrum in ruminants for the passive protection and the development of active immunity against parasites remains to be fully explored.     

A MUCOSAL DISEASE VIRUS AS A CAUSE OF ABORTION HAIRY BIRTH COAT AND UNTHRIFTINESS IN SHEEP

A condition resembling border disease has been transmitted by the inoculation of pregnant ewes with material from affected lambs. Forty-nine merino ewes, mated to merino rams 7 to 87 days previously, were inoculated with an homogenate of brain, spinal cord and spleen from affected lambs. Mummified foetuses, abortions and stillbirths were observed, and lambs with hairy birth coats were born to ewes inoculated between days 12 to 70 of gestation. A mucosal disease virus (MDV), present in the original material, was recovered from the aborted foetuses and lambs. Attempts to induce passive protection using bovine anti-serum to the C24V strain of MDV were not successful. The condition was also transmitted by inoculation of pregnant ewes with a cell culture supernatant prepared from tissue cultures that had been inoculated with an organ homogenate pool. MDV was present in the supernatant and was recovered from aborted foetuses and lambs. It is suggested that a condition in sheep in Australia resembling border disease is due to the infection of the pregnant ewe by a mucosal disease virus.     

The effect of increasing the Vitamin B12 status of Romney ewes on foetal liver Vitamin B12, milk Vitamin B12 and liver Vitamin B12 concentrations in suckling lambs

AIM: To determine the effect of increasing the Vitamin B12 status of the ewe on the Vitamin B12 supply to the suckling lamb. METHODS: The Vitamin B12 status of the ewe was increased during gestation and lactation by three injections of a long-acting preparation of Vitamin B12 microencapsulated in an organic acid polymer. The Vitamin B12 status of the ewes and suckling lambs was assessed from changes in serum and liver Vitamin B12 concentrations. RESULTS: Compared to untreated animals, serum and liver Vitamin B12 concentrations of the treated ewes were increased at least 70% during gestation. Foetal liver Vitamin B12 concentrations were increased 270%. Over the lactation, ewe serum and milk Vitamin B12 concentrations were increased at least 200% and 44%, respectively. The liver Vitamin B12 stores of the newborn lambs from Vitamin B12-treated ewes were depleted within 58 days. There were no significant differences in the serum Vitamin B12 concentrations of suckling lambs from Vitamin B12-treated and untreated ewes. CONCLUSION: Ewes with a high Vitamin B12 status will ensure an adequate supply of Vitamin B12 to their lambs for at least the first 30 days of life. CLINICAL SIGNIFICANCE: In flocks grazing Co-deficient pastures, treating ewes with a long-acting Vitamin B12 supplement at mating will prevent Vitamin B12 (Co) deficiency in ewes, as well as their lambs, until they can be treated at tailing at 4-6 weeks of age.     

Evaluating the effect of calcium,magnesium and sodium supplementation of Merino ewes on their lambs' growth

Our study aimed to investigate responses to supplementation of calcium (Ca), magnesium (Mg) and sodium (Na) to lactating ewes and lambs grazing barley forage from lamb marking to weaning. A 10-ha paddock sown to barley was subdivided into eight plots as four replicates of two treatments. Merino ewes (n = 104) with lambs at foot were stratified to the eight plots (13 ewes and 21 lambs/plot) based on number of lambs (twin or single) and ewes' weight. Supplemented groups had access to mineral supplements (30 g/ewe/day) supplying 12 g/ewe/day ground limestone, 12 g/ewe/day Causmag® and 6 g/ewe/day coarse salt in a ratio of 2: 2: 1 by weight (as fed) from day 0 (a day before lamb marking) after sample collection. Control groups were not supplemented with minerals. Blood, milk and urine samples from ewes and blood from lambs were collected at different time points, namely, a day prior to lamb marking (day 0), 14 days after the commencement of study (day 14), and 28 days after the commencement of study (day 28). Weight of the lambs was also recorded at each time point. We found that the concentration of the forage minerals (Ca, Mg and potassium (K)) was lower on day 28 than on day 0 (P < 0.025). Liveweight gain was greater in the first 14 days compared with the second weight gain period (P < 0.001). The interaction of time and treatment was significant for liveweight (P < 0.001). Due to the improvement in weight gain of supplemented lambs, we recommend that mineral supplementation during late lactation is beneficial considering the low cost of minerals, even though the mineral content of the forage was not deficient.