ahmad zare shahneh

Inflammatory-dependent events in the aged commercial laying hens reduce production rate and egg quality. Our study was aimed to evaluate the phosphodiesterase (PDE) inhibitor Theophylline on the ovarian and fallopian-inflammatory traits in the commercial laying hens at the late stage of the production period. Twenty-four White Leghorn hens aged 92 weeks were used for four weeks to be orally supplemented by Theophylline (3 mg/kg/Body weight, BW). Ovulation rate and follicular growth were measured by laying frequency and, visual evaluation after euthanizing, respectively. The mRNA expressions of follicular and fallopian cyclooxygenases 1 and 2 (COX-1,-2), and cytokines were detected by real-time PCR. Plasma concentrations of ovarian hormones (Two hours after lighting) were measured via enzyme-linked immunosorbant assay (ELISA). The results showed that the mRNA expression of the IL-1β, IL-6 and TNF-α in the ovary and IL-1β and TNF-α in the infundibulum were significantly decreased (P<0.01) by Theophylline treatment; however, the mRNA abundance of COX-2 and IL-10 in both of ovary and infundibulum were increased (P<0.01). Plasma concentrations of estradiol and progesterone were elevated (P<0.05) in the hens treated with Theophylline. Ovulation rate and follicular size were not significantly (P>0.05) influenced by Theophylline. As a phosphodiesterase inhibitor, Theophylline retained the laying frequency in addition to enhancing its anti-inflammatory capability in the late stage of production period in laying hens.

Since the phenomenon of inflammation is considered as one of the significant challenges in different sectors of the livestock industry, so this study aims to evaluate the inflammatory strategy of Theophylline (a Phosphodiesterase, PDE inhibitor) on some production characteristics in laying hens at the late period of egg production (The severity of chronic ovarian inflammation increases due to consecutive ovulation in older laying hens), egg quality characteristics and histological evaluations of infundibulum were performed.

The study was conducted in a completely randomized design, over a period of 4 weeks, using 24 laying hens of W-36 line strains (older than 90 weeks). The birds were randomly divided into two treatments (including a level with a concentration of 3 mg perlive body weight as orally and a control treatment) with 3 replications per treatment and 4 birds per replication. Percentage of oviposition, mean egg weight and feed conversion ratio were calculated. Eggs were collected randomly and weekly and the ratio of shell weight to egg weight, egg shell thickness, egg specific gravity, units and yolk index were measured. Blood were sampled from wing vain to measure glucose, triglyceride and cholesterol. At the end of the study period, the chickens were dissected and the appearance of the ovaries and ovarian tumors were assessed. Also, after evaluating the appearance of the follicles, tissue was sampled from the area closest to the infundibulum to the ovary.

The results showed that despite being none significant result in body weight and daily food intake (p>0.05), usage of PDE inhibitor Theophylline caused to increase in pre-ovulatory follicle diameter (F1) (p≤0.05). Among the quality characteristics of eggs as an indicator of anti-inflammatory effects on oviduct function, egg white height, egg height and shell thickness in birds under the influence of theophylline increased significantly (p<0.05). theophylline supplementation increased blood triglycerides in treated birds (p<0.05). The ratio of control treatment, the use of theophylline could improve the histological anti-inflammatory properties of oviduct by increasing the stability of the epithelial cilia of infundibulum.

The supplementation of PDE inhibitor Theophylline could improve some of the production characteristics and improve some egg quality indicators due to its anti-inflammatory effects in oviduct.

Current investigation was performed to study the effect of Propylthiouracil on immune cell count and antibody production in Ross 308 broiler breeder roosters with a total of 66 birds in complete randomized design during primary and booster vaccination. The birds were randomly allocated in two experimental groups including replication in each. All chickens were reared in the same condition according to the breeder's management guide for entire 18-wk duration (control group) or up to the point of dietary treatment with Propylthiouracil (0.1% w: w) for 6 weeks through 6 to 12 wk of age (Hypothyroidism group). Birds of both experimental groups were vaccinated at age 9 and 15 wk with using of Bronchitis vaccine Nobilis 4/91 (Intervet, Netherland) in drinking water and then were bled at age 12 and 18 wk. Consumption of Propylthiouracil decrease serum thyroxin (tetraiodothyronine), triiodothyronine and production of antibody hypothyroid group versus control group at age of 12 wk (P<0.05) but there were no differences between experiential groups at age 18 wk (P>0.05). Study of total cell count showed induction of hypothyroidism lead to lower total white cell count and percentage of lymphocyte cell in hypothyroid group versus control group after primary vaccination at age of 12 wk (P<0.05) but there were not significant difference between both experimental group following booster vaccination at age 18 wk (P>0.05). It seems supplementation of feed with Propyl-2-thiouracil and consequent hypothyroidism leads to higher immune response while populations of blood cells had decreased.

The effects of MitoTEMPO, a mitochondria-targeted antioxidant, and its non-targeted parent, TEMPO, on bovine oocyte maturation competence have not been determined so far. Hence, our study was aimed to investigate the effects of supplementing maturation medium with different concentrations of MitoTEMPO (0.00, 0.10, 1.00 and 10.00 µM) or TEMPO (0.00, 5.00, 10.00 and 15.00 mM) on in vitro maturation (IVM) and fertilization (IVF) of bovine oocytes. The oocytes after IVM and IVF were evaluated for the signs of nuclear maturation and normal fertilization. The average number of spermatozoa penetrated per oocyte and the level of intracellular reactive oxygen species (ROS) were also evaluated. The results showed that percentages of bovine oocytes reached the metaphase II stage of meiosis were significantly higher in the 1.00 µM MitoTEMPO group compared to the control group (without antioxidant supplementation). The normal fertilization rate also tended to be greater in this group than the control group. In comparison with the control group, the medium supplementation with 1.00 µM MitoTEMPO led to a significant decrease in the intracellular ROS level. The average number of spermatozoa penetrated per oocyte was not significantly different among the antioxidant-treated and the non-treated groups. The TEMPO addition to the maturation medium affected neither the rate of maturation/fertilization nor the level of intracellular ROS in bovine oocytes. Based on these results, we concluded that MitoTEMPO at a concentration of 1.00 µM had beneficial effects on the quality and fertilization potential of bovine oocytes.

The design of this study was done to investigate the effects of inhibiting the activity of beta-adrenergic receptors by supplementation of different concentrations of propranolol (as a none-selective inhibitor of beta- adrenergic receptors) on some of the performance characteristics in laying hens at the end of the economic production period and the qualitative traits of eggs. The experiment was performed in a complete randomized design, over a 26-day period, using 64 laying hens (90 weeks’ age) included 4 treatments (including control treatment and propranolol treatment with concentrations of 1, 2, and 3 mg Per kilogram of live body weight) with 4 repetitions and each repetition consisted of 4 birds, and some of the performance characteristics, follicular size (F1-F5) and egg quality were measured and calculated. The data obtained from the performance characteristics show that the usage of all concentrations of this inhibitor causes the significant increase in the laying percentage, improvement of feed conversion ratio. Propranolol also significantly increased feed intake and F1 follicle size at a concentration of 3 mg. Regarding the qualitative parameters of eggs, the usage of this inhibitor causes the significant increase in the thickness of the egg shell, the significant increase in the shell weight and ratio of the shell to the total weight of the eggs and the improvement of the Hue index in concentrations of 2 and 3 mg propranolol in treated birds. Therefore, it can be concluded that supplementation of different concentrations of propranolol in this study has been capable of improving some of the performance and qualitative characteristics of eggs in laying hens at the end of the production period.

Since inflammation is considered as one of the major challenges in different parts of the livestock industry, this study was conducted to evaluate the inflammatory strategy of combination and simultaneous usage of beta-2 agonist and glucocorticoid drugs on some performance characteristics in laying hens at late production stage and some of qualitative characteristics. The research was conducted in a completely randomized design, during a period of about 4 weeks, using 112 laying hens of High Line W-36 strains (older than 90 weeks). Birds were randomly divided to seven treatments (including one level of beta-2 agonist drug, one level of glucocorticoid drug, three combined levels of these drugs, one beta-blocking treatment and control) with 4 replicates per treatment and 4 birds were put on each replicate. The results indicated that the laying percentage and feed intake increased in beta-agonist and beta-blocker treatments (P <0.05) and decreased significantly in glucocorticoid and combination treatments (P <0.05). Also, in beta-2 agonist treatment, body weight and egg weight were significantly increased (P <0.05). In contrast, these parameters significantly decreased (P <0.05) in glucocorticoid and combination treatments. However, shell thickness significantly increased (P <0.05) in some combination treatments. Therefore, it can be concluded that beta-agonist as a stimulant of inflammation (in some tissues such as the ovary) has a positive effect on the performance parameters, while egg qualitative parameters performed better in the glucocorticoid and combined treatments which act as anti-inflammatory stimulants in the body.

The effect of addition of different concentrations of folic acid (vitamin B9) to the culture medium on in vitro maturation of bovine oocytes was investigated in two experiments. Optimization of bovine oocyte maturation medium is one of the strategies affecting quality of maturity and fertility, ultimately resulting in increasing the quality of produced bovine embryos. In the 1st experiment, to specify the concentrations of folic acid and homocysteine, ovarian follicles were divided into two categories including follicles with more or less than eight mm of diameter. Then, the concentrations were measured in both follicle groups as well as a commercial culture medium. In the second experiment, bovine ovaries were transferred to the laboratory immediately after slaughter and the cumulus-oocyte complexes were collected by aspiration from 2-8 mm diameter follicles. Oocytes were randomly divided into four groups and different levels of folic acid (0, 10, 100 and 1000 ng/ml) were added to maturation medium based on the results of the first experiment. Following incubation of oocytes, the percentage of mature oocytes was determined by Hoechst staining. The concentrations of folic acid and homocysteine in follicles with diameter of less than eight mm was higher than those with diameter of greater than eight mm, as well as the culture medium Supplementation of maturation medium with 100 ng/ml folic acid increased the percentage of metaphase-II oocytes compared to the control (P <0.05). Considering the concentrations of folic acid and homocysteine in the medium, results showed that the addition of folic acid improves in vitro maturation of bovine oocytes.

The effect of Pioglitazone and Curcumin on lipid metabolism and plasma metabolites of broiler breeder was investigated as a completely randomized design with three treatments and four replications by using of 60 hens at age 45 weeks during 10 weeks. Experimental treatments including: 1) Control (basal diet), 2) Adding 20 mg/bird/day Pioglitazone to diet and, 3) Adding 20 mg/bird/day Curcumin to diet. At the end of experiment, blood samples were collected, and birds were slaughtered. The results showed that hens receiving Pioglitazone or Curcumin had higher egg production and shell thickness when compared with control group (p<0.05). However, the yolk and egg weight of birds in the control group were higher than two another groups (p<0.05). Plasma concentrations of glucose, triglycerides and cholesterol were lower in hens feeding Pioglitazone or Curcumin than control (p<0.05). Liver and abdominal fat weight and adipocyte diameter were lower in birds receiving Pioglitazone or Curcumin (p<0.05). Based on current results, dietary supplementation of Pioglitazone or Curcumin, through lowering plasma lipids and subsequently positive influence on abdominal fat tissue and liver, could improve production in broiler breeders.

Trend in body weight, thyroid hormones and some blood metabolites changes in broiler breeder hens after the peak egg production was studied. Blood samples from 20 Ross 308 broiler breeder hens, were investigated from 47 to 55 weeks of age. Plasma lipid profile including cholesterol, triglyceride, lipoprotein LDL, lipoprotein HDL, and also glucose concentrations were measured every two weeks, and plasma concentrations of triiodothyronine (T3) and tetradothyronine (T4), aspartate aminotransferase (GOT) and alanine aminotransferase (GPT) were measured at the beginning and at the end of the experimental period. Results showed that body weight and plasma concentration of glucose, triglycerides, cholesterol, and LDL were increased, and concentrations of HDL were decreased (P<0.05) over the experimental period. Plasma T4 concentrations were decreased with age of the birds (P<0.05), while T3 concentrations were not affected. Plasma GOT and GPT enzymes activities were increased over the experiment period (P<0.05). In general, by increasing of age and subsequently body weight of breeder hens, several major changes have been occurred in blood metabolites and metabolic hormones which could reduce production and reproduction of broiler breeder flocks.

The present study was conducted to investigate the effect of dietary Curcumin supplementation on histological parameters of testis in aged Ross 308 broiler breeder roosters. A total of twelve 48-week old broiler breeder roosters in a completely randomized design were randomly assigned to four treatments and three replicates during a 13 weeks of experimental period. Treatments included no dietary Curcumin supplementation (control group), and daily supplementation of 10, 20, and 30 mg Curcumin/birds as mixed in the basal diet. At the end of the experimental period, all of the roosters were slaughtered, and testis tissue samples were collected. Testicular weight was higher in the roosters that daily received 30 mg Curcumin compared with the control group (P<0.05). Dietary supplementation of 20 and 30 mg Curcumin/day increased the diameter of seminiferous tubule compared to the control group (P<0.05). Seminiferous epithelium thickness was dose-dependently increased in Curcumin-supplemented birds compared to the control group (P<0.05). The number of spermatogonia cells was increased in all treatment groups compared to the control group (P<0.05). The number of Leydig cells was also increased in roosters received 20 and 20 mg Curcumin/day compared to the control birds (P<0.05). However, treatments did not affect the number of testis blood vessels (P>0.05). According to the results of the present study, dietary supplementation of 30 mg Curcumin/day/bird improves testis histological parameters in aged broiler breeder roosters.

The aim of this study was to compare the effects of using different levels of royal jelly in semen extender on viatal characteristics of goat sperm after freezing. Semen was collected from four adult bucks twice a week and samples pooled together. Sperm samples (six repeats) containing royal jelly in four levels (0.5, 1, 1.5 and 2%) had been frozen. After semen samples freezing – were thawed and examined in terms of mobility, survival and integrity of the membrane. Average total motility and survival at 1% royal jelly were higher than other treatment and control groups (P<0.05). A significant difference in terms of linearity motility of sperm and plasma membrane integrity was not observed between the treated groups and control group. A significant reduction was observed in the rate of other parameters velocity in Diluent contain royal jelly with the control group (P<0.05). Therefore, the use of royal jelly in goat semen diluent can improve some sperm parameters after freezing process.

This study was carried out to determined the reproductive performance (calving interval, days open) of Tehran and Alborz provinces Holstein Cows and some factors affecting it, while using 90824 records which were collected by Animal Breeding Center from years2001to2011.mean and standard error of calving interval 401/75±70/52 days, days open 123/31±59/86 days were estimated. The effect of herd, lactation number and milk yield on reproductive performance were significant (p

The objective of the present study was to determine the effects of feeding high levels of L-arginine on growth performance, blood metabolites, and carcass meat quality of female Ross broiler chickens at the starter period. In this experiment, 192 day old chicks were fed with 4 dietary treatments (100%, 153%, 168% and 183% of digestible arginine, based on the Ross catalogue recommendation) with 4 replications in a completely randomized design from day 1 to 10. On 10th day of experiment, chicks were weighed, feed consumption was recorded, and feed efficiency was calculated. Also, three chickens per replication were selected after sampling, blood were euthanized to measure breast and thigh muscle weights, meat quality of the breast muscle (color, pH, and shear force). Data were analyzed based using proc GLM of SAS software. According to the results, the highest increasing percentage for body weight (2.33%), feed efficiency (6.35%), relative weight of breast (22.16%) and thigh (17.53%) muscles were observed in diet with 168% digestible arginine relative to control group (P<0.05). Also, the highest increasing percentage in plasma triiodothyronine (60.45%), thyroxine (26.91%), and relative triiodothyronine to thyroxine (25.91%) was observed in diet with 183% digestible arginine relative to control group (P<0.01). On the other hand, in 183% digestible arginine group noticeable decrease in percentages of plasma cholesterol (14.93%) and triglyceride (25.19%) concentrations, shear force (26.39%) and 24 (2.05%) and 48 (2.63%) h meat pH was observed(P<0.05) relative to the control group. The overall results of this study showed that consumption level of 168% digestible arginine, as based of Ross catalogue recommendation, had the best desirable results on growth, meat quality andplasma metabolites.

The aim of the present study was to determine the effect of dietary supplementation of pioglitazone (PGT) during transition period on the ovarian function and the incidence of several diseases after parturition. Eighty Holstein cows were randomly allocatted to four treatment groups (n=20) using a 2×2 factorial design. Pioglitazone was fed for 14 day before the expected parturition time, or for 21 days after parturition, or furing both pre- and post-partum period. The cows received either 0 or 6 mg PGT/kg live weight. Data on the incidence of production diseases (laminitis, mastitis, cystic ovaries, infected uterus and inactive ovaries) and the day of ovulation were recorded and analyzed using the GENMOD and GLM procedures of SAS. Postpartum supplementation of PGT decreased the mean days to ovulation (P<0.02). The percentage of cows which ovulated during 14 DIM was significantly increased when PGT was supplemented postpartum (P<0.03). PGT supplementation during prepartum (p<0.01) and postpartum (P<0.10) periods decreased laminitis. Prepartum PGT supplementation had no significant effect on mastitis incidence. Prepartum (P<0.03) and postpartum (P<0.08) PGT supplementation resulted in decreased uterine infections. Postpartum PGT supplementation significantly decreased the proportion of cystic cows (P<0.04). PGT had no significant effect on the percentage of cows with inactive ovaries (P>0.05). In conclusion, supplementation of PGT during transition period in dairy cows may be beneficial in decreasing the incidence of some postpartum diseases, and may enhance ovarian cyclicity after parturition.

The objective of the present study was to investigate the effects of high dietary levels of L-arginine during starter period on growth، intestine morphology and immune system of female Ross broiler chicks. In this experiment، 192 day old female Ross broiler chicks were fed with 4 dietary treatments in a completely randomized design، in which each dietary treatment included 4 replications. Dietary treatments included 100%، 153%، 168% and 183% of digestible arginine، based on the Ross recommendation، and were fed from day 1 to 10. On d 10 of the experiment، chicks were weighed and feed consumption was recorded. Then، three chicks per replication were slaughtered in order to survey intestinal histology and immune system. The results showed that high dietary levels of arginine had an increasing effect (P<0. 01) on 10th day body weight، feed efficiency، immune system characteristics، weight and length of small intestine، and its villus height and crypt depth. According to the results of this study، 168% digestible arginine، based on the Ross recommendation، had the best desirable results on growth improvement of broiler chicks and it also improved weight، length and histology of small intestine، and immune characteristics.

The aim of this study was to evaluate the effect of estradiol (E2)، oxytocin (OT)، relaxin (relaximol) injection and prostaglandin E1 (misoprostol) suppository on the cervix dilation، time of cervical dilation persistency and pregnancy rate of Zandi ewes using artificial insemination. Eighty 3-4 years old and 55±2. 5 kg weight ewes were used for this study. In experiment 1، the ewes were assigned to four equally groups. The groups were received 100 µl E2، 100 IU of OT، 5 ml relaximol and 200 µg misoprostol، respectively. Then، cervical dilation and time of cervical dilation persistency were examined at four times. E2 had no effect on cervical dilation and time of cervical dilation persistency (P>0. 05). Using of OT، relaximol and misoprostol lead to cervical dilation (P<0. 05). In experiment 2، the estrous synchronization was accomplished using CIDR insertion for 12 days. At the time of CIDR removal، 500 IU of eCG injected in to the ewes and then assigned to four equally groups. The control group received no cervical dilator treatment. Other three groups received the same treatment as the first experiment. According to the best time of cervical dilation in experiment 1، ewes were inseminated transcervically in the times of 20 and 40 min and 5 hours after treating، respectively، at 54 hours after eCG injection. Fifty days after insemination، pregnancy rate were recognized via ultrasonography diagnosis. Pregnancy rate in OT group was higher (P<0. 05) than misoprostol and relaximol groups (60% vs 25 and 10%، respectively). However، there were no significant differences (P>0. 05) between oxytocin and control group (60% vs 50%) in pregnancy rate. In conclusion، injection of oxytocin dilate the cervical canal and improved pregnancy rate in Zandi ewes، therefore this could be used as an instrument for improving pregnancy rate during artificial insemination.

To current knowledge, different oocyte''s recovery method and various seasons have profound impact on in vitro embryo production (IVEP). The aim of this study was to define an efficient recovery method for oocytes harvesting from slaughterhouse material in different seasons, and their effects on IVEP yield. Ovaries from slaughtered ewes in breeding season (BS) and non-breeding season (NBS) were collected from a local abattoir. The oocytes were recovered through aspiration, centrifugation (ORC), puncture and slicing, and categorized into three classes (I, oocytes with more than three layers of cumulus cells; II, less than three layers with damaged cumulus cells; III, denuded oocytes). After cultivation in TCM 199 for 24 hours, matured oocytes were subjected to in vitro fertilization (IVF) and in vitro culture (IVC). The oocyte recovery using ORC in BS and NBS was significantly higher (P < 0.05) compared with other recovery methods. No significant dissimilarities in the proportion of oocytes reaching M-II stage were recorded when using different oocyte recovery methods in different seasons. Aspiration resulted in lower (P < 0.05) proportion of class I (BS, 60.0 ± 2.1; NBS, 51.1 ± 2.1) compared to ORC (BS, 82.0 ± 1.2; NBS, 70.0 ± 1.2), slicing (BS, 80.0 ± 2.1; NBS, 71.0 ± 1.4) and puncture (BS, 80.0 ± 1.5; NBS, 72.0 ± 2.0). Monospermy and blastocyst development rates were significantly higher using ORC than other recovery techniques in both BS and NBS. More oocytes with high quality, greater blastocyst development and oocyte recovery rates were achieved in BS. The results revealed that oocytes harvesting technique and season are effective in the rate of cleavage and blastocysts’ development, and suggest that despite same meiotic resumption rate in all treatments, it would be better to use ORC.

The purpose of this study was to determine the effects of different concentrations of vitamin E (Vit. E) in the quality of preserved stallion semen at 5ᵒC for a period of 48 h. Semen was collected and most (≥90%) seminal plasma removed by centrifugation at 600 × g. Pooled samples divided in four equal parts and diluted with extenders that was supplemented with different concentrations of Vit. E [(0 (control، C)، 5 and 10 mM)] and DMSO positive control group [as vitamin E solvent، (DC)] to a final concentration of 50 × 106 sperm/ml. Motility، viability، plasma membrane integrity، total abnormality and lipid peroxidation were determined at 0، 6، 24 and 48h. The results showed that 5mM vitamin E resulted in higher viability and plasma membrane integrity compared to control after 48 h of storage (P<0. 05). Different concentrations of vitamin E had no significant effects on sperm motility and total abnormality compared to C and DC extender (P>0. 05). Also، 5mM Vit. E was decreased lipid peroxidation compared C and DC extenders after 48h of storage (P<0. 05). In conclusion، between above-mentioned different concentrations، 5mM Vit. E could improve Caspian stallion sperm quality during cooled-storage at 5°C.

Equine chorionic gonadotropin (eCG) is commonly used in association with a progestagen treatment to synchronize estrus of goats and ewes during breeding and non-breeding seasons. Classical purification of the eCG from serum includes pH fractionation with metaphosphoric acid two ethanol precipitation steps as well as dialysis followed by fixed-bed chromatography. The aim of the current study was to develop an accurate and fast method for production and purification of eCG using a polyclonal antibody assay. The blood samples (300 mL) were taken from the jugular vein of 17 mares on days 50, 70 and 90 of pregnancy. Plasma of the samples was siphoned and phenol solution was added to the plasma and stored in the refrigerator until eCG extraction. To prepare the polyclonal antibody against eCG, four male rabbits, about four months old with 2 kg weight, were chosen. A basic immunization was done by injecting 25 IU of eCG to the rabbits. Ouchterlony assay or double immunodiffusion test was used to assess the immunization and the titer of antiserum against eCG. eCG was purified from the plasma via the solid-phase extraction (SPE) method. Results based on agarose-gel double immunodiffusion test showed that rabbits were completely immunized. SDS-PAGE analysis showed purified eCG is extracted without any significant contamination. The extraction of eCG with polyclonal antibody using the SPE method and production of anti- eCG antiserum in rabbits is suitable and may be a cost effective method for large scale production of eCG and anti-eCG antiserum in Iran.

Chronic active adrenocorticotropin hormone (ACTH) immunization of ewes (with a previous history of immunization) resulted in elevated titres of antibody against ACTH, which induced a reduction in circulating levels of cortisol. The aim of the present study was to investigate: a) the influence of active immunization against ACTH on milk production of the ewe as assessed by milk intake of the lamb measured with two different methods, b) whether the stimulation of levels of β-end and α-MSH in the circulation can result in a similar increase in the expression of these peptides in the milk of the lactating ewe, thereby producing a milk with high analgesic properties. Ten primiparous Merino ewes (4-5 years old) during their first 5 weeks of lactation were used in the experiment. Milk intake of each lamb can be used to give the ewe’s milk yield per unit time, and this can be used for secretion of peptides over time. This was determined by two different techniques: the deuterium oxide method and the weigh-suck-weigh method. β-end, α-MSH and cortisol were measured in blood samples and β-end, α-MSH in milk samples using RIAs (Radio Immune Assay). Plasma β-end and α-MSH in ACTH-immune animals increased to 3 and 38-fold respectively, although the level of α-MSH is most likely exaggerated by the presence of α-MSH antibodies in the ACTH immune plasma, as α-MSH comprises the N-terminal 13 amino acids of ACTH. Antibodies also were detected in the plasma of lambs of immune ewes after birth, at levels, which were comparable to those measured in the ewes during the period of colostrum production and thereafter decreased to much lower levels by the end of the experiment. Plasma β-end and α-MSH in the lambs of immune ewes were significantly higher than those measured in the lambs of control ewes. The immunization procedure had no effect on feed intake, live weight gain and milk production of ewes nor was the growth rate or milk intake of the lambs altered. The expression of β-end and α-MSH in milk was also unaffected by the high concentrations of these hormones in the circulation of immune ewes.