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BackgroundOn two farms it was noted that after routine treatment with monepantel, fecal egg counts failed to drop. This was accompanied by lambs mortality due to Haemonchus contortus infection. The aim of this work was to evaluate the efficacy of monepantel to control gastrointestinal nematodes (GIN) in two sheep farms, in Uruguay.FindingsA Fecal Egg Count Reduction Test (FECRT) was subsequently performed at the Experimental Stations Glencoe of INIA Tacuarembó (Farm 1) and Sheep Unit of INIA La Estanzuela (Farm 2) using the World Association for the Advancement of Veterinary Parasitology guidelines. On Farm 1 the FECRT was performed using 6–8 month old Corriedale or Merino Dohne x Corriedale male lambs naturally infected with GIN. On day 0 pre-treatment, three groups of 15 lambs each were selected, blocked by fecal egg count level (FEC) and randomly assigned to one of the following: Group 0 = untreated control, Group 1 = treated with monepantel (Zolvix®, Novartis Animal Health Inc.) from stock previously purchased; Group 2 = treated with monepantel from stock provided by the supplier, at the recommended dose of 2.5 mg/kg of body weight. Fecal samples were collected directly from the rectum from each lamb on day 0 and on day 9 post-treatment. On Farm 2, the FECRT was conducted on a group of 8 month old male lambs Milchschaff x Finn. At this farm, 10 lambs were randomly allocated to be treated with monepantel (Group 1) and 10 lambs were randomly allocated to remain as untreated control (Group 0) using the same protocols as Farm 1.On farm 1 the FECR was 0.0% (95% CI = 0.0 – 49.0) and 42.0% (95% CI = 0.0 – 75.0) for Group 1 and Group 2 respectively. For Farm 2, the FECR was 82.1% (95% CI = 36.0 – 99.0). Haemonchus spp was the resistant genus.ConclusionsPoor effcicacy of monepantel in treating GIN parasites was demonstrated on both farms.

Nutrition and suckling are largely recognised as the most important factors affecting the postpartum period and consequently the reproductive efficiency of beef cattle. The aim of this study was to evaluate the effects of body condition score (BCS) and suckling restriction with and without the presence of the calf on milk production, reproductive efficiency and calf performance. Sixty-three crossbred (Angus · Hereford) multiparous cows were managed to maintain different BCS at calving and thereafter (low vs moderate; L, n = 31 and M, n = 32). Within each group of BCS (L and M) at week 9 postpartum (66 AE 0.88 days postpartum) cows were assigned to three suckling treatments (ST): (i) suckling ad libitum (S, n = 20); (ii) calves fitted with nose plates during 14 days remaining with their dams (NP, n = 22); and (iii) calves were completely removed from their dams for 14 days, and thereafter returned (CR, n = 21). Milk production was assessed by milking procedure at Day 65 (the day before onset of ST) and every 20-22 days until the end of the experiment. Cows were bled via jugular venipuncture every 28 days from Day -98 (Day 0 = calving) until Day 66. From Day 66 cows were bled every 7 days until the end of the mating period (Day 128). Concentrations of progesterone, non-esterified fatty acids and b-hydroxybutyrate acid and insulin were measured. Presence of corpus luteum (CL) was recorded and maximum follicle diameter was measured in all cows from the onset of the ST (Day 66) and during the following 4 weeks (until Day 94) in a weekly frequency. At Day 94, more cows (P < 0.001) in NP and in CR had CL compared with S cows (68, 57 and 21% for NP, CR and S, respectively). At that time, more cows in M-BCS presented CL than cows in L-BCS (77 vs 25; P < 0.0001). Within M-BCS, there were no differences in milk production between ST groups, while L-BCS cows with NP or CR produced less milk than S cows. Calf liveweight at weaning was 159.3 AE 3.1, 150.1 AE 2.9 and 147.0 AE 3.1 kg for S, NP and CR, respectively (P < 0.001). Suckling restriction with and without the presence of the calf had similar effects on reproductive performance, milk production and calf growth, while BCS interacted with ST to influence milk production. These results indicate that temporary suckling restriction could be an excellent management tool to increase reproductive performance of cows in moderate condition.

Abrupt weaning, a usual management in sheep productive systems, may provoke behavioural and physiological responses indicative of stress in ewes and lambs. Progesterone (P4) has anxiolytic and sedative effects through the union of its metabolites that contain 3a-hydroxyl group to the g-aminobutyricacid A receptor. Our first aim was to determine whether P4 administration reduces the behavioural and physiological responses of ewes to abrupt weaning of lambs. A complementary aim was to determine whether P4 treatment affects the milk yield and composition of ewes, and the BW of their lambs. In experiment 1, seven ewes received P4 treatment for 32 days (group E1-P4), and eight ewes remained as an untreated control group (group E1-C). BW of the lambs was recorded during P4 treatment. Lambs were weaned at 59 days (Day 0 5 weaning). The main behaviours of the ewes before and after weaning were recorded using 10 min scan sampling. The ewes' serum total protein, albumin and globulin concentrations were measured before and after weaning of the lambs. In experiment 2, milk yield and composition were determined in two different groups of six ewes treated with P4 (group E2-P4) for 16 days and in five untreated controls (group E2-C). The BW of lambs increased with time ( P 5 0.001) in both groups and did not differ. The percentage of observations in which the ewes were seen pacing on Day 0 was greater in the E1-C group than in the E1-P4 group ( P 5 0.0007). Similarly, the percentage of observations in which the ewes were recorded vocalizing on Day 0 was greater in the E1-C group than in the E1-P4 group ( P 5 0.04). The percentage of observations in which E1-C ewes were recorded lying did not change from Days 0 to 1; however, it increased in E1-P4 ewes. Total serum protein concentration did not change in E1-P4 ewes from Days 0 to 3, although a decrease was seen in E1-C ewes ( P 5 0.04). Serum globulin concentration was greater in E1-P4 ewes on Day 3 than in E1-C ewes (P 5 0.0008). In experiment 2, there were no differences between E2-P4 and E2-C ewes in terms of milk yield, protein, fat and lactose content. Progesterone administration reduced the behavioural and physiological responses of ewes to abrupt weaning of lambs, and this effect was not mediated by changes in milk yield and composition, or by lambs' BW.

BackgroundThe aim of this study was to estimate variance components and to identify genomic regions and pathways associated with resistance to gastrointestinal parasites, particularly Haemonchus contortus, in a breed of sheep adapted to tropical climate. Phenotypes evaluations were performed to verify resistance to gastrointestinal parasites, and were divided into two categories: i) farm phenotypes, assessing body condition score (BCS), degree of anemia assessed by the famacha chart (FAM), fur score (FS) and feces consistency (FC); and ii) lab phenotypes, comprising blood analyses for hematocrit (HCT), white blood cell count (WBC), red blood cell count (RBC), hemoglobin (HGB), platelets (PLT) and transformed (log10) egg per gram of feces (EPGlog). A total of 576 animals were genotyped with the Ovine SNP12k BeadChip (Illumina, Inc.), that contains 12,785 bialleleic SNP markers. The variance components were estimated using a single trait model by single step genomic BLUP procedure.ResultsThe overall linkage disequilibrium (LD) mean between pairs of markers measured by r 2 was 0.23. The overall LD mean between markers considering windows up to 10 Mb was 0.07. The mean LD between adjacent SNPs across autosomes ranged from 0.02 to 0.10. Heritability estimates were low for EPGlog (0.11), moderate for RBC (0.18), PLT (0.17) HCT (0.20), HGB (0.16) and WBC (0.22), and high for FAM (0.35). A total of 22, 21, 23, 20, 26, 25 and 23 windows for EPGlog for FAM, WBC, RBC, PLT, HCT and HGB traits were identified, respectively. Among the associated windows, 10 were shown to be common to HCT and HGB traits on OAR1, OAR2, OAR3, OAR5, OAR8 and OAR15.ConclusionThe traits indicating gastrointestinal parasites resistance presented an adequate genetic variability to respond to selection in Santa Inês breed, and it is expected a higher genetic gain for FAM trait when compared to the others. The level of LD estimated for markers separated by less than 1 Mb indicated that the Ovine SNP12k BeadChip might be a suitable tool for identifying genomic regions associated with traits related to gastrointestinal parasite resistance. Several candidate genes related to immune system development and activation, inflammatory response, regulation of lymphocytes and leukocytes proliferation were found. These genes may help in the selection of animals with higher resistance to parasites.Electronic supplementary materialThe online version of this article (doi:10.1186/s40104-017-0190-4) contains supplementary material, which is available to authorized users.

In sheep production systems based on extensive grazing, neonatal mortality often reaches 15% to 20% of lambs born, and the mortality rate can be doubled in the case of multiple births. An important contributing factor is the nutrition of the mother because it affects the amount of colostrum available at birth. Ewes carrying multiple lambs have higher energy requirements than ewes carrying a single lamb and this problem is compounded by limitations to voluntary feed intake as the gravid uterus compresses the rumen. This combination of factors means that the nutritional requirements of the ewe carrying multiple lambs can rarely be met by the supply of pasture alone. This problem can overcome by supplementation with energy during the last week of pregnancy, a treatment that increases colostrum production and also reduces colostrum viscosity, making it easier for the neonatal lamb to suck. In addition, litter size and nutrition both accelerate the decline in concentration of circulating progesterone that, in turn, triggers the onsets of both birth and lactogenesis, and thus ensures the synchrony of these two events. Furthermore, the presence of colostrum in the gut of the lamb increases its ability to recognize its mother, and thus improves mother-young bonding. Most cereal grains that are rich in energy in the form of starch, when used as supplements in late pregnancy will increase colostrum production by 90% to 185% above control (unsupplemented) values. Variation among types of cereal grain in the response they induce may be due to differences in the amount of starch digested post-ruminally. As a percentage of grain dry matter intake, the amount of starch entering the lower digestive tract is 14% for maize, 8.5% for barley and 2% for oats. Supplements of high quality protein from legumes and oleiferous seeds can also increase colostrum production but they are less effective than cereal grains. In conclusion, short-term supplementation before parturition, particularly with energy-rich concentrates, can improve colostrum production, help meet the energy and immunological requirements for new-born lambs, and improve lamb survival.

In this investigation we tested the hypothesis that static body condition (BC) of the ewe affects oestradiol and FSH with implications for subsequent follicular growth and turn-over. Sixteen Polwarth ewes were selected from a flock according to their BC score (scale: 1 emaciated; 5 obese). High BC (HBC) ewes (no. = 8) had a BC score of 4·1 (s.e. 0·1) and low BC (LBC) ewes (no. = 8) had a BC score of 1·9 (s.e. 0·1). Daily ultrasound examinations were performed and blood samples for progesterone, oestradiol and follicle-stimulating hormone (FSH) determination were collected. All HBC ewes (8/8) exhibited three waves of follicular development, while four LBC ewes (4/8) had two waves and the other four (4/8) had three waves of follicular development (P ≤ 0·05) during the interovulatory period. Overall, the emergences of 33 out of 44 follicular waves were preceded by significant increases in FSH concentrations. Maximum FSH concentrations were detected 0·9 ± 0·2 days before wave emergence. Oestradiol concentrations increased significantly during the growing phase in 38 out of 44 large follicles. A negative correlation between oestradiol and FSH was observed in HBC ewes. A similar inhibitory effect of oestradiol on FSH was observed in LBC ewes, irrespective of whether they developed two or three follicular waves. However, a longer period with high FSH was needed to promote the emergence of the second follicular wave in two-wave LBC ewes. Four HBC ewes had twin ovulations but no LBC ewes did (P ≤ 0·05). In HBC ewes, the follicular phase was characterized by lower oestradiol (6·5 (s.e. 1·0) pmol/l) but higher mean FSH concentrations (2·4 (s.e.0·4) μg/l) than in LBC ewes (8·9 (s.e. 1·2) pmol/l and 2·0 (s.e. 0·3) μg/l, respectively; P ≤ 0·05). The present results suggest that BC influences the pattern of follicular dynamics through changes in the endocrine milieu. Higher FSH concentrations during the follicular phase in HBC ewes, which allowed an extended period of follicular recruitment from a significantly larger pool of small antral follicles could explain the higher ovulation rate observed in this group.

The experiment tested the hypothesis that short-term feeding of barley just before lambing would be as effective as maize in stimulating early production of colostrum. Both grains are high in starch, and should provide a substrate for lactose which, in turn, promotes lactogenesis. Thirty-five Corriedale ewes bearing single foetuses and 25 bearing twin-foetuses from a synchronised mating were fed on pasture during most of gestation. Fourteen days before the expected time of lambing the single-and twinbearing ewes were allocated to three treatments and fed (1) a basal diet of lucerne hay to meet their nutrient requirements, (2) the basal diet plus a supplement of whole barley; or (3) the basal diet plus a supplement of cracked maize. The twin-bearing control ewes accumulated more colostrum than the single-bearing control ewes at birth (292 v. 190 g). However, supplementation with barley or maize increased the colostrum at birth to 360 and 541 g in singles and 648 and 623 g in twins. We conclude that barley is a good alternative to maize to stimulate production of colostrum especially in twin-bearing ewes whose lambs are the most likely to benefit from the supplement.