Influence of passively acquired colostral immunity on neonatal lamb mortality in Ethiopian highland sheep

Refining livestock mortality indicators: a systematic review

Background: Livestock mortality impacts farmer livelihoods and household nutrition. Capturing trends in livestock mortality at localised or national levels is essential to planning, monitoring and evaluating interventions and programs aimed at decreasing mortality rates. However, livestock mortality data is disparate, and indicators used have not been standardised. This review aims to assess livestock mortality indicator definitions reported in literature, and define the ages where mortality has greatest impact. Methods: A systematic review was conducted, limited to articles focussed on mortality of cattle, sheep and goats. Peer-reviewed articles in Web of Science until year 2020 were assessed for inclusion of age-based definitions for mortality indicators and data on age distribution of mortality. Indicator definitions for each species were collated and similar terms and age groups most targeted were compared. The cumulative distribution of age at mortality was compared across studies graphically where possible; otherwise, age patterns for mortality were collated. Results: Most studies reported mortality risk rather than rate, and there was little agreement between indicator definitions used in the literature. The most common indicators reported were perinatal and neonatal mortality in cattle, and for perinatal, neonatal and pre-weaning mortality indicators for sheep and goats. Direct comparison of age distribution of mortality was only possible for cattle, which found that approximately 80% of all mortalities within the first 12 months had occurred by six months of age. A significant finding of the study is the variation in age groups for which mortality is reported, which impedes the comparison of mortality risk across studies, particularly for sheep and goats. Conclusions: This study demonstrates the importance and value of standardising mortality risk indicators for general use, including a young stock mortality risk indicator measuring mortality in the highest risk period of birth to six months of age in cattle, sheep and goats.

General and type 2 parvovirus-specific passive immune transfer in puppies - Evaluation by early growth

Failure of passive immune transfer put puppies at a higher risk of neonatal and weaning mortality due to low immune protection against infectious agents. The aim of this study was to investigate the evolution of the general via serum IgG concentration (IgG) and the specific via serum maternally derived canine parvovirus type 2-specific antibody titer (CPV2 MDA) passive immune transfer within the first 4 weeks of age. Furthermore, the relationship between general and specific immune transfer and the possibility of non-invasive evaluation was assessed. Puppies (169) were weighed systematically between birth and Day 28. IgG and CPV2 MDA were assayed in serum samples at 2 and at 28 days of age. At Day 2, there was a positive correlation between IgG and CPV2 MDA (ρ = 0.71; p < 0.001). At Day 2, 17.9% (27/151) of puppies presented a deficit of passive immune transfer according to IgG result (defined as IgG < 2.3 g/L) and 25.8% (39/151) of puppies were under the minimal protective CPV2 MDA titer (defined as <1:160). No correlation between IgG and CPV2 MDA was observed at Day 28 (ρ = 0.14; p = 0.11). Growth rate within the first 48 hours <-2.7% allowed to distinguish puppies at high risk of the general and specific passive immune failure (Youden's index = 0.79 and 0.75, respectively). The threshold value of early growth rate, although applicable only in puppies non-supplemented with milk replacer, allows identifying via non-invasive way individuals requiring a special care. Further investigation of the mechanism of passive immune transfer in dogs is necessary to understand the relationship between the general and specific immunoglobulin levels.

Transferência de imunidade passiva em cordeiros de corte manejados extensivamente em clima tropical

Aspectos relacionados à transferência de imunidade passiva (TIP) foram estudados em 290 cordeiros recém-nascidos, cruzas Texel, manejados extensivamente em contato permanente com as suas mães, e criados em clima tropical. Amostras de sangue foram colhidas dos cordeiros uma única vez entre 24 e 36 horas de vida para obtenção do soro sanguíneo. Foram determinadas a atividade da gama glutamiltransferase e as concentrações de proteínas totais por refratometria e colorimetria, de albumina, alfa, beta e gamaglobulinas por eletroforese e de IgG estimada pela turvação pelo sulfato de zinco. Os cordeiros foram agrupados de acordo com o sexo, o número de partos das ovelhas, o escore de condição corporal (ECC) da ovelha, o número de cordeiros nascidos, o peso e a vitalidade ao nascimento. Os fatores de risco para a ocorrência de falha na transferência de imunidade passiva (FTIP) foram identificados e a sua associação com a mortalidade de cordeiros foi testada. Foram estabelecidas correlações entre as variáveis estudadas. A TIP não foi influenciada pelo sexo, pelo número de partos ou pelo ECC das ovelhas. Houve diferenças entre os cordeiros únicos e gêmeos e entre os que nasceram com peso >3 kg e < 3 kg. A FTIP foi pouco frequente (12,4%), mais provável em gêmeos (p=0,026) e em cordeiros leves (p<0,001) e esteve fortemente associada com a mortalidade dos cordeiros até os 60 dias de vida (p<0,001). A taxa de mortalidade geral foi de 11,3%; e 30,5% dos cordeiros com FTIP morreram, quase todos no primeiro mês de vida. A concentração de proteína total determinada por refratometria se correlacionou (p<0,001) com as concentrações de gamaglobulinas (r=0,816) e de IgG (r=0,810) e o valor crítico < 5,0g/dL para a proteína total pode ser admitido como indicador de FTIP. Sob condições de clima tropical a FTIP pode ser considerada pouco frequente em cordeiros mestiços de corte, entretanto, a vigilância e os cuidados devem ser intensificados no caso do nascimento de cordeiros gêmeos com peso reduzido.

Effects of supplementation with digestible undegradable protein in late pregnancy on ewe colostrums production and lamb output to weaning

The aim of this study was to investigate the effects of supplementation with digestible undegradable protein (DUP) in diet during late pregnancy on colostrum production, lamb survival and growth. For 3 weeks prior to lambing, 41 Afshari ewes were assigned at random to three dietary treatments, namely a control (CDUP), moderate (MDUP) and high (HDUP) DUP group. The ewes (n = 14) in CDUP group were fed a protein maintenance level for pregnant ewes [83 g metabolizable protein (MP)/kg dry matter (DM)], while ewes in the MDUP (n = 13) and HDUP (n = 14) groups were fed diets provided 14% (94.7 g MP/kg DM) and 24% (104.3 g MP/kg DM) MP in excess of these requirements respectively, which this increment was coming from DUP (DUP/MP ratio 43.8; 51.0% and 57.6% respectively). All diets were isoenergetic (12 MJ ME/kg DM). All ewes received the same lactation diet after lambing. Ewes in HDUP tend to produce more colostrums (p < 0.1) and had higher protein, fat, and solids non-fat content (p < 0.05) in colostrums during the first 24 h after lambing. MDUP group had higher colostrum yield compared to CDUP (p < 0.1). The changes in body weight and body condition score of ewes were similar for all diets but placenta weight was higher in MDUP group (p < 0.05) than for HDUP and CDUP ewes. Lamb body weight at weaning was higher for males compared to females (p < 0.05), but was not different between treatments. HDUP ewes had higher blood glucose concentration in the pre-lambing period than other treatments (p < 0.05). In this period, increasing the level of DUP in diet increased the content of blood urea nitrogen (p < 0.05). It was concluded that increasing the DUP content of diet for 3 weeks prior to lambing above the standard requirements resulted in an increase in colostrums production but had no effect on lamb outcome to weaning.

Effects of newborn characteristics and length of colostrum feeding period on passive immune transfer in goat kids

Majorera goat kids (n = 200) were used to evaluate the effects of litter size, birth body weight, sex, and suckling duration on serum IgG concentrations. Kids were assigned to 1 of 3 experimental groups: litter size and sex were equally distributed in each group. In the first group, kids (n = 67) stayed with their dams for 24 h; in the second group, kids (n = 66) stayed with their dams for 48 h; and in the third group, kids (n = 67) stayed with their dams for 120 h. Blood samples were obtained every 24 h for 5 d, and serum IgG concentration was measured using radial immunodiffusion. In litter sizes of 1 to 2 kids, IgG blood serum concentration was significantly higher (18.30 +/- 5.40 mg/mL) than in litters of 3 kids (9.85 +/- 4.23 mg/mL). Kid sex did not affect IgG blood serum concentrations. Suckling duration did not affect kid serum IgG concentrations. In conclusion, kids with low birth body weight (<2.8 kg) or from litters of 3 may need special attention. If newborn goat kids are allowed to suckle colostrum for at least 24 h from their dams, this seems to be sufficient time to ingest enough IgG from colostrum to achieve an adequate serum IgG concentration and passive immune protection to avoid failure of passive immune transfer.

Short communication: Addition of milk replacer to colostrum whey: effect on immunoglobulin G passive transfer in Majorera kids

Forty-two Majorera kids (21 males and 21 females) were assigned to 3 groups, a colostrum group (C), a colostrum whey group (CW), and a colostrum whey plus milk replacer group (CWMR). All kids were fed twice on the first day and received 4 g of IgG/kg of body weight. No differences were found in serum IgG among the different treatments. Kid serum IgG concentrations on d 2 were 14.57, 17.25, and 13.32 mg/mL in the C, CW, and CWMR group, respectively. Labor time per animal was higher in the C and CW treatments than in the CWMR group (24.2 +/- 2.3, 20.9 +/- 3.4, and 16.1 +/- 1.5 min, respectively). This new management system may decrease labor costs during the colostrum feeding period.

Mortalidade perinatal em cabritos no semi-árido da Paraíba

As causas de mortalidade perinatal em cabritos foram estudadas de maio de 2002 a agosto de 2004. Em 118 cabritos necropsiados as causas de morte foram: infecção neonatal (50%), distocia (12,71%), complexo hipotermia/inanição (11,86%), malformações (7,62%), síndrome do cabrito mole (6,77%) e abortos (1,69%). Com relação ao momento da morte 1,69% dos cabritos morreram antes do parto, 16,94% durante o parto e 81,34 % após o nascimento. A alta ocorrência de infecções neonatais, distocias e hipotermia/inanição é provavelmente devido a fatores relacionados com erros no manejo sanitário, reprodutivo e nutricional. Artogripose dos membros anteriores foi a principal malformação observada. Este defeito é endêmico em rebanhos de caprinos no semi-árido do Brasil. A maioria das mortes ocorreu após o nascimento (25,42%) e do quarto ao vigésimo dia de vida (38,98%) sugerindo que o cuidado com os cabritos durante os primeiros 28 dias de vida é importante para melhorar as taxas de sobrevivência dos mesmos.

Factors related to the risk of neonatal mortality, birth-weight and serum immunoglobulin concentration in lambs in the UK

Neonatal-lamb mortality represents an economic loss and welfare concern. Two factors often associated with the risk of mortality are birth-weight and serum immunoglobulin concentration. We used data from two studies to investigate risk factors for mortality between 2 and 14 days of age and factors affecting birth-weight and serum immunoglobulin concentration at 48h of age. Dataset 1 included 1339 lambs born on eight farms during the 1995 spring lambing season; dataset 2 included 3172 lambs on seven farms during the 1991 spring lambing season. To account for some of the potential clustering within the data, multilevel models were used. Most (>75%) of the variation in the risk of mortality was at the lamb level. In dataset 1, factors significantly associated with increased odds of lamb mortality included low birth-weight and low serum immunoglobulin concentration. In dataset 2, significant risk factors for mortality included low birth-weight, ewe body-condition score, being born late in the season (relative to other lambs on the farm) and being born in multiple litters. There was a significant interaction between the effects of litter size and birth-weight. (Serum immunoglobulin concentration was not available for dataset 2.) More than half of the variation in birth-weight was at the ewe level, 27% at the lamb level, and 18% at the farm level (dataset 1). Single birth and being male were associated with increased birth-weight in both datasets. In dataset 2 only, increasing ewe condition score and birth early in the study period were also associated with increased birth-weight. Fifty-six percent of the variation in immunoglobulin concentration was at the lamb level, 36% at the ewe level and only 7% at the farm level. Factors associated with reduced serum immunoglobulin concentration included early or late birth in the lambing season, being born later than 14 days after the first lamb born on the farm, multiple-birth litters and maternal mastitis.

Risk factors for lamb mortality on UK sheep farms

Data on neonatal-lamb mortality and flock history were recorded by veterinary students working on 108 sheep farms in the UK in Spring 1997. The mean reported mortality incidence risk was 10.0% (median 9%; inter-quartile range 5.9-12.3%). The outcomes were incidence risks of stillbirth, perinatal (within 24h of birth) mortality and postnatal (>24h after birth) mortality. Exposures were screened for univariable associations with mortality risk. Logistic binomial multiple regressions adjusted for confounding, with farm as a random effect. This study has raised hypotheses for management factors associated with lamb mortality that warrant further study. Intensive rearing systems appear to be associated with increased perinatal and postnatal mortality, although housing ewes at lambing was associated with a decreased risk of stillbirth. High perinatal mortality also was associated with poor mothering-pen hygiene, flocks that foster more lambs, and failure to provide appropriate nursing for sick lambs. Larger flocks, poor ewe condition at breeding, and flocks with higher ewe-replacement rates were associated with higher postnatal mortality.