Causes of lamb morbidity and mortality in the Ethiopian highlands

Interventions to reduce camel and small ruminant young stock morbidity and mortality in Ethiopia

Morbidity and mortality of young stock is a challenge for livestock producers globally. In Ethiopia, where camels and small ruminants (sheep and goats) are essential smallholder and pastoral livestock, young stock losses can cause severe consequences to livelihoods. This pilot study, part of a Government-led Young Stock Mortality Reduction Consortium project, was undertaken to identify and evaluate interventions to reduce young stock mortality in mixed crop-livestock and pastoral production systems in Ethiopia. Pastoralists and mixed crop-livestock farmers were enrolled by convenience sampling across four regions. Households were sampled with questionnaire surveys to establish baseline mortality risk and prevalence of diarrhoea and respiratory disease in animals younger than one year, and followed longitudinally over a one-year period, with final evaluations conducted from March to July 2020. Mortality risk and prevalence of diarrhoea and respiratory disease before and after implementation were compared using Poisson regression models including household as random effect. Prior to intervention, median camel mortality, prevalence of diarrhoea, and respiratory disease across production systems in the different households was 0.4, 0.44 and 0.2, respectively. This compared to median pastoralist small ruminant mortality risk and prevalence of diarrhoea and respiratory disease of 0.45, 0.32 and 0.18, respectively. Post-intervention, median camel mortality, prevalence of diarrhoea and respiratory disease dropped to 0.1, 0.08 and 0. Similarly, more than half of the small ruminant households reported no mortality, and no cases of diarrhoea or respiratory disease. In camels, rate ratios of mortality risk, prevalence of diarrhoea, and respiratory disease post-intervention compared to the baseline were 0.41, 0.41 and 0.37. In small ruminants, rate ratios were 0.33, 0.35 and 0.46. All reductions were statistically significant (p < 0.01). Generally, pastoralists experienced higher mortality and disease prevalence compared to mixed crop-livestock smallholders, and the effect of intervention was slightly higher in pastoralist households. The pilot study findings demonstrated highly significant reductions in mortality and risk of diarrhoea and respiratory disease post-interventions. However, not all households benefitted from the interventions, with a few households reporting increased mortality and morbidity. Many households had very few animals which made it challenging to measure impact and the study was conducted over a single year, without a control group, so between year effects could not be accounted for in the reductions observed. These findings should contribute to improved livestock productivity in Ethiopia.

Effects of parenteral administration of tylosin and ivermectin on abomasal emptying rate in healthy suckling lambs by use of nuclear scintigraphy

Abomasal hypomotility is one of the important causes of neonatal mortality in small ruminants. Various pharmaceutical agents have been studied to address this problem in large ruminants. The aim of this study was to determine the effect of parenteral administration of tylosin and ivermectin on abomasal emptying rate in neonatal suckling lambs. Abomasal emptying rate was assessed using nuclear scintigraphic method in 10 healthy female Iranian fat tailed Ghezel lambs. Each lamb was tested three times, once as a control (1 ml of saline 0.9%, IM) and twice after the injection of tylosin (17.6 mg/kg, IM) and ivermectin (200 μg/kg, SC) in a crossover study. Based on radiopharmaceutical counts, remnant activity in abomasums at 90 min were 48.3 ± 3.5, 45.6 ± 7.5 and 41.6 ± 2.9% in control, tylosin and ivermectin groups, respectively. Administration of tylosin (p = 0.049) and ivermectin (p = 0.045) to lambs, significantly caused faster abomasal emptying rate compared to control. Evaluating the ROIs revealed that the half emptying time (T_1/2) in control, tylosin and ivermectin groups were 67.1 ± 8.6, 62.6 ± 14.2 and 54.3 ± 9.9 min, respectively. These difference between all groups, statistically were significant (p = 0.026). However, the clinical efficacy of abomasal emptying rate facilitating by tylosin or ivermectin administration in lambs remains to be determined.

Effects of Rosmarinus officinalis L. essential oils supplementation on digestion, colostrum production of dairy ewes and lamb mortality and growth

The aim of this study was to evaluate the effect of rosemary essential oils (REO) and the forage nature on ewes' performances, immune response and lambs' growth and mortality. Forty-eight dairy ewes (Sicilo-Sarde) were fed oat-hay or oat-silage supplemented with 400 g of concentrate during pregnancy and 600 g during postpartum. The experimental concentrate contained the same mixture as the control (barley, soybean meal and mineral vitamin supplement) more 0.6 g/kg of REO. Two groups were obtained with each forage (Hay groups: H-C and H-REO; Silage groups: S-C and S-REO). REO increased the dry matter (DM) intake, the nitrogen intake and retention being higher with the silage groups (P < 0.05). REO increased solid non-fat (P = 0.004) and fat contents of colostrum which was higher with hay (P = 0.002). REO decreased lamb mortality (P < 0.05) which averaged 21% for control groups and 6% for H-REO, while no mortality was recorded with S-REO. REO dietary supply improved forage intake and tended to ameliorate colostrum production; it could be a natural additive to improve ewes' performances.

Passive transfer of maternal immunity in the dromedary (Camelus dromedarius), involvement of heavy chain antibodies

In many mammalian species, newborns are agammaglobulinemic; thus, colostrum and milk are the main sources of early protective antibodies. These antibodies are produced in the mother's serum and transferred to mammalian glands a few days before parturition. Here, we have studied the transfer of immunity from a she-camel immunized with human serum albumin (HSA) to her calf via colostrum and milk. Our results show that HSA-specific antibodies are produced in the mother's serum and are subsequently transferred to her colostrum. These specific antibodies are then transferred by suckling to the calf. The calf serum did not contain HSA-reactive antibodies at parturition and before the first feed, after suckling, a rise in reactivity was observed peaking at 24 h postpartum. The involvement of heavy chain antibodies (HCAbs) in the process of immunity transfer was also examined, and it was found that they were also transferred from the colostrum to the calf serum like conventional antibodies.

Diversity of bacterial species in the nasal cavity of sheep in the highlands of Ethiopia and first report of Histophilus somni in the country

A study was conducted to isolate bacterial species/pathogens from the nasal cavity of apparently healthy and pneumonic sheep. Nasal swabs were collected aseptically, transported in tryptose soya broth and incubated for 24 h. Then, each swab was streaked onto chocolate and blood agar for culture. Bacterial species were identified following standard bacteriological procedures. Accordingly, a total of 1,556 bacteria were isolated from 960 nasal swabs collected from three different highland areas of Ethiopia, namely Debre Berhan, Asella, and Gimba. In Debre Berhan, 140 Mannheimia haemolytica, 81 Histophilus somni, 57 Staphylococcus species, and 52 Bibersteinia trehalosi were isolated. While from Gimba M. haemolytica, Staphylococcus, Streptococcus, and H. somni were isolated at rates of 25.2, 15.9, 11.4, and 5.9 %, respectively, of the total 647 bacterial species. In Asella from 352 bacterial species isolated, 93 (26.4 %) were M. haemolytica, 48 (13.6 %) were Staphylococcus species, 26 (7.4 %) were B. trehalosi, and 17 (4.8 %) H. somni were recognized. Further identification and characterization using BIOLOG identification system Enterococcus avium and Sphingomonas sanguinis were identified at 100 % probability, while, H. somni and Actinobacillus lignerisii were suggested by the system. The study showed that a variety of bacterial species colonize the nasal cavity of the Ethiopian highland sheep with variable proportion between healthy and pneumonic ones. To our knowledge, this is the first report on isolation of H. somni, an important pathogen in cattle, from the respiratory tract of a ruminant species in the country.

Avoiding hypothermia, an intervention to prevent morbidity and mortality from pneumonia in young children

Observations and experiments in animals and human beings grant plausibility to the hypothesis that hypothermia is a risk factor for pneumonia. Exposure of body to cold stress causes alterations in the systemic and local defenses against respiratory infections, favoring the infection by inhalation of pathogens normally present in the oropharynx. Neonates and young infants with hypothermia have an increased risk of death; however, there is no strong demonstration that hypothermia leads to pneumonia in these children. Studies that properly addressed the problem of confounding variables have shown an association between cold weather and pneumonia incidence. Probably the strongest evidence that supports the plausibility of the hypothesis is provided by the controlled comparison between patients with traumatic brain injury treated with hypothermia and those treated under normal body temperature. The association between exposure to cold and pneumonia is strong enough to warrant further research focused in young children in developing countries.

Mortalidade perinatal de cordeiros no semi-árido da Paraíba

As causas de mortalidade perinatal em ovinos foram estudadas de março de 2002 a outubro 2004 em 27 fazendas da região semi-árida da Paraíba. De 90 cordeiros necropsiados, 41,1% morreram de infecções neonatais, 23,3% por malformações, 10% por inanição/hipotermia, 10% por distocia, 2,2% por predação e 4,4% foram abortos sem causa identificada. Em relação ao momento da morte, 4,4% dos cordeiros morreram antes do parto, 10% durante o parto, 30% no primeiro dia de vida, 20% entre o 2º e 5º dia e 35,6% entre o 4º e 28º dia após o parto. A assistência das ovelhas durante o parto, a desinfecção do umbigo dos cordeiros, a ingestão de colostro 2 a 6 horas após o parto, e a manutenção das ovelhas em locais adequados durante e após o parto contribuiriam para diminuir as mortes perinatais por distocia e infecções neonatais. A alta freqüência de malformações, em diferentes raças, sugere que esses defeitos sejam causados por uma planta tóxica. Os principais defeitos observados foram a flexão permanente dos membros anteriores, braquignatismo, fenda palatina e outras alterações dos ossos da cabeça. Recentemente foi demonstrado o efeito teratogênico de Mimosa tenuiflora ("jurema-preta"), uma planta muito comum na região semi-árida, nas áreas de caatinga, que aparentemente é responsável pelas malformações. Os cordeiros mortos por inanição/hipotermia tiveram baixo peso ao nascimento (1,37 ± 0,7kg) o que sugere que a principal causa dessas mortes é a deficiente nutrição da mãe durante o último terço da gestação. Considerando-se que na região nordeste, na maioria das fazendas, os carneiros permanecem com as ovelhas durante todo o ano, a adoção de uma estação de monta definida contribuiria para a diminuição da mortalidade perinatal.

Fox predation as a cause of lamb mortality on hill farms

Data collected between 1993 and 1996 from two Scottish hill farms were used to assess the potential importance of predation by foxes as a cause of lamb mortality. Farm 1 was in Midlothian and farm 2 in West Perthshire. Overall lamb mortality rates from birth onwards were 10.2 per cent for farm 1 and 9.3 per cent for farm 2. Sixteen lambs were identified as killed by foxes on the two farms during the four-year period. The minimum rates of fox predation were 0.6 per cent for farm 1 and 0.2 per cent for farm 2. All confirmed cases of fox predation were recorded during the period until the lambs were marked at about six weeks of age, and during this period another 53 lambs went missing from the two farms. Both groups of missing lambs were characterised by having significantly more siblings than the remaining lambs. A logistic regression model was able to classify the lambs killed by foxes and the missing lambs with 75 per cent accuracy on the basis of their birth rank alone. Of the total potential revenue from lamb production, the maximum losses due to confirmed fox predation in any one year were equivalent to 1.5 per cent on farm 1 and 0.6 per cent on farm 2.