Nitrogen metabolism by lactating ewes and their lambs

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

Colostrum and milk can transmit jaagsiekte retrovirus to lambs

Ovine pulmonary adenocarcinoma (OPA) is a contagious disease caused by jaagsiekte sheep retrovirus (JSRV). In the three studies performed, we have obtained data of the importance of colostrum/milk (C/M) in the transmission of JSRV. In the first study, a group of sheep from a flock with a long history of OPA, samples from colostrum and peripheral blood leucocytes (PBLs) were collected. Two specific PCRs (U3-LTR and env of the JSRV) were carried out. Using U3PCR 8/34 sheep were positive in colostrum whereas with envPCR 7/34 were positive. From these animals only one was positive with U3PCR in the PBLs. Evidence of the transmission of JSRV infection by C/M was obtained in two more separate studies. In the second study, PBLs from five lambs from JSRV+ ewes and two from JSRV-ewes were tested by the U3PCR. They were fed C/M by their mothers during 3 months and slaughtered 7 months after birth. Three out of five lambs from the JSRV+ sheep become PBL positive at 3-4 months old and the other two were also positive at 4-6 months of age. One lamb of the JSRV-sheep became also PBL positive at an age of 3 months. In the third study, a group of lambs from JSRV negative mothers were fed with C/M from JSRV+ sheep and housed in separate unit. For comparison, another group of the same origin and maintained in another different unit, were fed with C/M containing a JSRV virus preparation. All lambs were blood sampled monthly and JSRV infection was detected as early as 15 days and several times onwards in both groups. Control groups fed with C/M from JSRV free flock and JSRV blood test negative sheep were always negative. Together these results indicate that suckling is an important natural transmission route for JSRV.     

Protection of lambs against enteric colibacillosis by vaccination of ewes

Pregnant ewes were vaccinated twice, seven weeks and three weeks before lambing, with a multivalent formalin-killed Escherichia coli vaccine containing an added K99, F41 antigen preparation. Lambs born to vaccinated and unvaccinated ewes were exposed to oral infection with E coli B44 (09:K30, K99, F41). All 10 lambs from vaccinated ewes were protected whereas all 10 control lambs developed severe diarrhoea and five died or were killed in extremis. In the following year, previously immunised ewes were given a single dose of the vaccine two weeks before lambing. Eleven of their 12 lambs were protected against a similar challenge, which caused the death of six of eight control lambs and severe diarrhoea in the two survivors. Higher levels of antibody to the K99, F41 preparation were detected by enzyme-linked immunosorbent assay in the serum and colostrum from vaccinated ewes and in the serum of their lambs when compared with similar samples from control ewes and lambs.     

Effects of a controlled-release albendazole capsule on parasitism and production from grazing Merino ewes and lambs

SUMMARY: Effects of a controlled-release albendazole capsule (CRC) on nematode parasitism and production of Merino ewes and lambs were Investigated in a replicated grazing experiment between August 1986 and July 1989. The experiment was conducted on a site where the naturally occurring parasites were benzimidazole-resistant, with double the recommended dose of oxfendazole reducing faecal egg counts of Trichostrongylus colubriformis by less than 50%. Two CRC treatments were compared with a minimal treatment control and the widely-used strategic control program, Wormkill.
Egg counts and worm burdens of major parasite species of ewes and of lambs before and after weaning were significantly reduced by use of the CRC in ewes before lambing or in lambs at weaning. These parasitological effects were reflected in increased productivity of CRC ewes and lambs. Ewes given CRCs lost less weight and grew more wool during lactation than ewes given Wormkill or control treatments, while their lambs gained more weight and had heavier fleeces than lambs from Wormkill or control treatments. Where lambs were weaned by removing ewes from the lambing paddock, administration of the CRC at weaning to lambs whose dams had also been treated with the CRC did not result in improved production when compared with lambs from ewes dosed with CRCs and treated after weaning according to the Wormkill program. Some possible uses for the CRC in ewes and lambs were identified.     

Lactation curves of commercial ewes rearing lambs

Three-hour milk production measurements determined by machine milking at 3-d intervals throughout a 63-d lactation period were used to describe lactation curves for crossbred ewes lambing at 1 and 2 yr of age and rearing single and twin lambs. Age of ewe, type of rearing, and day of lactation affected (P < 0.05) milk production. Over the 63-d lactation, average daily milk production was 2.56 and 2.63 kg, respectively, for 1- and 2-yr-old ewes rearing single lambs and 2.73 and 3.47 kg, respectively, for 1- and 2-yr-old ewes rearing twins. Milk production of 2-yr-old ewes rearing twin lambs peaked at 21 d of lactation, and that of 1- and 2-yr-old ewes rearing singles peaked between 27 and 30 d of lactation. The largest differences in the lactation curves among age and rearing ewe classes were found in early lactation. These differences were reduced by midlactation, and by late lactation, milk production for all ewes was similar. Diurnal variation in milk production by ewes was evaluated in an 8 x 8 Latin square design. Diurnal variation in milk yield measurements of eight mature ewes, each bearing and rearing twin lambs, was similar between d 21 and 24 of lactation. Time of milk production measurements within a day did not affect yield determinations. Extrapolation from 3-h production estimates to daily milk production is valid in determining a ewe's milk contribution in support of lamb growth.     

Behavior of ewes and lambs subjected to restraint fostering

The objective of this study was to investigate the development of maternal-filial social attachments between ewes and alien lambs using the technique of "restraint fostering." Forty-eight to 72 h after parturition, 22 Targhee -type ewes were separated from their natural lambs, placed in restraining devices ( stanchions ) and each exposed to a single alien lamb. After a period of 1 or 4 d of restraint, the ewes were subjected to five 10-min lamb acceptance tests over a 48-h period. The observer recorded butts and butt attempts by the ewe and successful and unsuccessful suckle attempts by the lamb. The ewe-lamb pairs were then housed in pens with other groups of ewes and lambs and observed intermittently for acceptance behaviors. Six of the 14 ewes restrained for 4 d and none of the eight ewes restrained for 24 h met the criterion for successful adoption within 48 h. After being housed in group pens, adoptions were achieved by three ewes in the 1-d group and an additional four ewes in the group restrained for 4 d. Ewes restrained for 24 h were significantly more aggressive toward fostered young than ewes restrained for 4 d. In addition, the proportion of successful suckling attempts was significantly lower for lambs fostered on ewes in the 1-d group. Both groups showed a decline in butts and butt attempts over successive acceptance tests, but while the proportion of successful suckling attempts declined for lambs housed with 1-d ewes, they increased over time for lambs fostered on ewes restrained for 4 d.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of helminth infection on the pre-weaning production of ewes and lambs: comparison between safe and contaminated pasture

Comparison was made of the performances of cross-bred ewes and their lambs on pastures of low helminth infectivity ("safe" pastures) or contaminated pastures and at high or low stocking rates. Ewes grazing the safe, but not the contaminated, pastures were given a single pre-lambing drench. The largest difference in parasite infection between treatments was the level of exposure of sheep to Trichostrongylus spp, which was negligible on the safe pastures. The effects of parasite control on lamb growth were significant only in twins during the last 2 months before weaning. However, 22% of lambs on contaminated plots became soiled in the breech area and 38% were flystruck, compared with 8% and 10% respectively for lambs on the safe pastures. Ewe bodyweight gains were greater at low than at high stocking rate and were not affected by the parasite control treatments; differences in breech soiling and fly strike were similar to those in the lambs. Most importantly the parasite treatment produced a highly significant effect on ewe fleece weight at weaning. Ewes drenched and lambing on the safe pastures produced an extra 0.43 kg of wool, calculated to represent an increase of at least 40% during this period at the low-level of parasitic infection.     

Environmental factors that influence milk production of Pantaneiro ewes and the weight gain of their lambs during the pre-weaning period

The main objective of this research was to conduct an exploratory study of the lactation curve in order to characterize the productive potential of Pantaneiro ewes and lambs. Fifty ewes were bred using four rams in two different mating seasons. The ewes were kept with their lambs on pasture of Brachiaria brizantha. Ewe body score, ewe weight, and lamb weight were evaluated. Milk sampling was performed every week. In the morning for milk collections, the ewes were treated with 1 UI of oxytocin (intramuscular) for complete milking. Lambs were separated from the ewes for 4 h and milk collections were performed. The total milk production over 24 h was estimated by multiplying the production of this period (4 h) by 6. The data were analyzed using the MIXED procedure (P?<?0.05) in SAS. Milk production data were fitted to the curve using the incomplete gamma function of Wood, and lamb growth data were fitted using the Gompertiz equation. The average milk production of the ewes was 1.03 kg/day^?1. Younger ewes had the lowest milk production (18?=?798?±?330, 24?=?1001?±?440, 36?=?1100?±?490, and 48?=?1106?±?490 g/day^?1). Ewe body score at lambing affected initial milk production (1.0?=?816?±?660, 1.5?=?1089?±?105, and 2.0?=?1424?±?1600 g/day^?1). Lambs were weaned with an average weight of 20.3 kg. Daily weight gain from birth to weaning was 181 g. Locally adapted Pantaneiro ewes showed a linear decreasing lactation curve, with reduced production from the second week of lactation. Overall, evaluation of the dairy production and lamb performance revealed great variation, denoting potential for selection.     

Thyroid histological changes in lambs from iodine-supplemented and untreated ewes

AIM: To identify the histological changes in the thyroid associated with subclinical goitre. METHOD: Thyroids were histologically examined from lambs that died within 24 hours of birth in a trial to investigate the effect of iodine supplementation to Merino ewes on perinatal mortality. RESULTS: Thyroids with follicles depleted of colloid, infolded and lined by columnar epithelium are indicative of hypothyroidism. These findings can occur in thyroids considered to be in the normal weight range of less than 1.3 g. CONCLUSION: Thyroid histological changes are a useful aid in diagnosing subclinical goitre.     

Responses of pregnant ewes and young lambs to cold exposure

The effects of cold stress were studied in pregnant ewes during the last three weeks of gestation and in their progeny during the first three days of life. In general, ewes were unaffected by treatment whereas changes were observed in the cold-stressed lambs. Cold-induced changes in lambs included physical weakness, depression, and poor nursing response. Serum concentrations of glucose and insulin were lowered whereas concentrations of blood urea nitrogen, alkaline phosphatase, aspartate aminotransferase, lactate dehydrogenase, triglycerides, and cortisol tended to be higher in cold exposed lambs. The mortality rate was higher (40%) in cold-stressed lambs than in lambs kept at warmer temperatures (10%). At necropsy, cold-exposed lambs had reduced amounts of adipose tissue in perirenal areas, and extensive subcutaneous hemorrhages and edema in the distal portions of the thoracic and pelvic limbs.     

Prevention of goitre in new-born lambs from kale-fed ewes

Milk urea concentrations in dairy cattle. There has been increased use of milk urea concentration as an indicator of dietary protein intake and protein metabolism in dairy cattle over recent years. The value of milk urea content data in predicting dietary composition, particularly for pasture-fed cattle, has not been well described.

Protein metabolism and urea synthesis. Many factors influence the degradation of dietary proteins in the rumen, post-ruminal protein metabolism and urea synthesis in cattle. Strong positive correlations between nitrogenous fertiliser use and the crude protein content of pastures were identified by use of meta-analysis. Similar strong positive correlations were noted between dietary protein intake, rumen ammonia and plasma urea concentrations. The costs of urea synthesis include energy losses, and importantly, the loss of endogenous amino acids, which are deaminated in the synthesis of urea.

Milk urea as an indictor of protein metabolism. Urea concentrations in blood, plasma and milk are strongly correlated. Milk is an adequate indicator of blood and plasma urea content, but non-nutritional factors may significantly influence milk urea concentrations. Recommendations for dietary protein management based on milk urea concentrations must be undertaken with care.     

Encephalopathy caused by Talisia esculenta intoxication in pregnant ewes and their newborn lambs

An outbreak of acute encephalopathy occurred in pregnant ewes and their newborn lambs associated with consumption of Talisia esculenta fruits and bark. Clinical signs in 5 adult pregnant ewes included drooling, bloat, tachypnea, depression, ataxia, body shaking, difficulty in rising, and recumbency. Three neonatal lambs born to some of those ewes had similar clinical signs. No significant gross abnormalities were observed on autopsy. Histologically, neuronal necrosis, axonal and dendritic swelling, and loss of Purkinje neurons were observed in the cerebellum. The observation of similar neurologic clinical signs and lesions in pregnant ewes and their neonatal lambs suggests that the toxic principle of T. esculenta crosses the placenta and reaches the fetus.     

The structure of vocalization of ewes and male lambs at pasture

We performed an analysis of the vocalization of 161 ewes and 50 male lambs that were pastured day and night. The vocalization structures of the phonetic notations of the opened-mouth from closed mouth /ηaee/ and /ηnaeee/ and closed-mouth /ηηηη/ of ewes, and the opened-mouth from closed-mouth /ηeee/ and /ηneeee/ and closed-mouth /ηηηη/ of male lambs were studied in terms of their audio characteristics. The items subject to analysis included duration of each vocalization, fundamental frequency, sound pressure and first formant (F1), second formant (F2), and third formant (F3). Among the male lambs, the duration of each call type showed significant differences depending on the behavior types or the target types, and the closed-mouth to open-mouth sounds, /ηeee/ and /ηneeee/ showed a tendency to be longer than the closed-mouth sound of /ηηηη/. A significant correlation ( r  = 0.9, P  < 0.05) was observed between the fundamental frequency and F1 with the /ηeee/ type of call of the male lambs when the vocalization was targeted toward the stockperson. When the ewes' behavior pattern was grazing and moving and the calling target was an ewe, the sound pressure significantly differed between /ηηηη/ and /ηnaeee/ ( P  < 0.05). From the analysis of the call durations, the fundamental frequencies, the sound pressures and formants, and the particular characteristics in sound structure were shown to vary according to the vocalization conditions and the situations, and where the animals were placed, even within the same call types.     

The effect of high calcium intake by pregnant Awassi ewes at late gestation on minerals status and performance of ewes and newborn lambs

Calcium (Ca) requirement increase rapidly by pregnant ewes at late gestation as a result of high fetal growth. Furthermore, Ca deficiency results in poor growth and bone development in growing newborn lambs. The aim of this study was to evaluate the effect of calcium supplementation (Calcium carbonate–CC) and vitamin AD₃E injection (75,000 IU/shot) to pregnant Awassi ewes at late gestation (− 45 days prepartum) on their mineral levels and performance of their newborn lambs. Forty pregnant Awassi ewes at late gestation (65 ± 6.1 kg) were selected before parturition (− 45 days; using hormonal sponges for estrus synchronization) and randomly divided to 4 dietary treatments. The treatments were: group 1 Control (1.4% CC); group 2 (2.4% CC); group 3 (1.4% CC + 2 shots vitamin AD3E at − 45 and − 21 days prepartum); group 4 (2.4% CC + 2 shots vitamin AD3E at − 45 and − 21 days prepartum). Blood samples were collected from ewes (− 45, 0 days prepartum: 30 and 60 days postpartum) and lambs (0, 30 and 60 days old). Average milk yield and samples were collected. Body weights of lambs were taken at birth, 30 and 60 days old. Blood serum and milk samples were prepared and analyzed by AAS for Ca, Mg, Co, Mn and Cu concentrations.Calcium concentrations in bloods serum of ewes, 0 and 60 days postpartum, and lambs at weaning (60 days old) from group 4 were significantly (P < 0.05) higher compared to other groups. No significant effect (P > 0.05) of treatment on Co, Mg and Cu in blood serum of ewes and lambs except for Cu concentration in ewes. Moreover, a significant increase (P < 0.01) in milk inorganic% (30 and 60 days samples) in ewes from group 2 when compared with other groups. The average milk yield (AMY) of ewes from group 2 and 4 at late stage of lactation (45–60 days) were significantly higher (P < 0.05) compared to groups 1 and 3. In addition, Ca% in colostrums samples from ewes in groups 2 and 4 were significantly higher (P < 0.01). The average daily gain (ADG) and total body gain for lambs up to weaning (60 days old) were significantly higher (P < 0.05) in groups 1 and 2 compared with the other groups.In conclusion, increasing level of Ca intake in feed of Awassi ewes at late gestation, with or without vitamin AD₃E injections, improve the calcium concentration in colostrums and blood serum of ewes and their lambs without negative effect in their health and performance.     

Isoenzymes of alkaline phosphatase in serum of lambs and ewes.

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