Academic literature on the topic 'Preweaning survival'

Effects of environmental factors viz, hirth year, parity, sex, birth type and season of birth on preweaning survival of Red Sokoto goats (RSG) using production records kept between 1978 - 1985 at the National Animal Production Research Institute (NAPRI), Shika-Zaria were investigated. Birth year, parity and season of birth significantly (P<0.05) affected preweaning survival while birth type and sex of kid did not. The mean survival to weaning at 3 months was 72% and was highest in does with 4 or more parities (77%) and least in primiparous does (66%). Survival was significantly higher during harmattan and worse during the dry season. Losses were more concentrated in the O 7 days of life in primiparous does during the dry season. Overall productivity of does and interac lions between parity and birth cype significantly affected survival. Breeding RSG older than one year to kids preferably during 'harmattan' would improve preweaning survival of the kids.

Abstract Several studies have suggested there is a critical relationship between piglet birth weight and preweaning mortality. Thus, the objective of the current work was to identify a birth weight threshold value for preweaning mortality. Birth weight and survival data from two studies involving a combined total of 4,068 piglets from 394 litters on four commercial farms (three European, one U.S.) were compiled for a pooled, multistudy analysis. Overall preweaning mortality across the two studies was 12.2%. Key variables used in the analysis were piglet birth weight (measured within 24 h of birth) and corresponding survival outcome (dead or live) by weaning at 3–4 wk of age. A mixed effects logistic regression model was fit to estimate the relationship between preweaning mortality and birth weight. A random effect of study was included to account for overall differences in mortality between the two studies. A piecewise linear predictor was selected to best represent the drastic decrease in preweaning mortality found as birth weight increased in the range of 0.5–1.0 kg and the less extreme change in weight above 1.0 kg. The change point of the birth weight and preweaning mortality model was determined by comparing model fit based on maximizing the likelihood over the interval ranging from 0.5 to 2.3 kg birth weight. Results from the analysis showed a curvilinear relationship between birth weight and preweaning mortality where the birth weight change point value or threshold value was 1.11 kg. In the combined data set, 15.2% of pigs had birth weights ≤1.11 kg. This subpopulation of pigs had a 34.4% preweaning mortality rate and represented 43% of total preweaning mortalities. These findings imply interventions targeted at reducing the incidence of piglets with birth weights ≤1.11 kg have potential to improve piglet survivability. Additional research is needed to validate 1.11 kg as the birth weight threshold for increased risk of preweaning mortality.

Index selection for reduced backfat thickness and increased postweaning growth rate resulted in increased preweaning death losses due either directly or indirectly to the sow in the Yorkshire and Hampshire breeds. This resulted in a reduced percentage of piglets weaned in the Yorkshire breed. Key words: Swine, selection index, preweaning period, mortality, survival

Abstract As a result of genetic selection for increased litter size, modern, highly prolific sows often produce large litters with an increased percentage of light birth weight (BiW) piglets compared with less prolific females. However, there is limited information elucidating what proportion of light BiW piglets that express compensatory growth and how these pigs might be identified at a young age. The objective of this study was to analyze the effect of birth weight and early phase growth on preweaning mortality, subsequent growth performance, and carcass characteristics of pigs. Individual records collected on 7,654 commercial crossbred pigs were used for analyses. A segmented regression model was used to analyze the effect of birth weight on preweaning survival and a series of mixed models were used to analyze the effect of birth weight (n = 7,654) group on weights recorded at: weaning (n = 6,777), nursery exit (n = 4,805), and finishing exit (n = 1,417); hot carcass weight (HCW), and lean percentage (n = 4,572). The effect of growth rate group was defined during suckling (< 225 or ≥ 225 g/d) or the nursery phase (< 424 or ≥ 424 g/d). Preweaning mortality, growth rate, BW, and carcass traits were adjusted to a standard age, and ADG and lean percentage were calculated. Results of segmented regression analysis showed that the slope of preweaning mortality on birth weights below 0.99 kg differed (P < 0.05) from the slope of preweaning mortality regressed on birth weights above 0.99 kg. The mixed model analyses showed a positive linear effect (P < 0.05) of BiW and quadratic effect (P < 0.05) of sow parity on age-adjusted finishing weight (FiW), HCW, and lean percentage. The positive influences of increasing BiW were greater (P < 0.05) in age-adjusted FiW and HCW for pigs with slow suckling growth rate compared with those with fast suckling growth rate. Pigs with fast nursery growth rate had greater (P < 0.05) age-adjusted FiW and HCW compared with the slow growing nursery contemporaries. In conclusion, piglets born weighing less than 1 kg were at a higher risk of preweaning mortality than piglets born weighing 1 kg or greater. Light BiW pigs, but not heavy BiW pigs, may lose compensatory growth capability if growth rate during the suckling phase is below the average level.

Summary. Preweaning lamb survival for intervals of up to 8 weeks was studied in the progeny of the local fat-tailed Naeemi and imported Border Leicester × Merino ewes mated to Naeemi rams. An intensive system of management with zero grazing was used to conform to the most probable type of production system to be used in Kuwait. The effects of year and season of lambing, litter size, sex, genetic group and birth weight were determined. Lamb survival rates from birth to 1 week, from 1 to 4 weeks and from 4 to 8 weeks were 96, 99 and 97% respectively. Overall survival from birth to weaning at 8 weeks was 91%. Genetic group, litter size, sex of lamb and year of lambing had no significant effects on survival. Season was significant from birth to 1 week, from 4 to 8 weeks and from birth to 8 weeks. Lamb birth weight was the most important factor affecting lamb survival, through a quadratic relationship between weight and survival.

The preweaning calf survival (SW) is one of the main economic bottlenecks of beef cattle rearing systems, however there is still few quantitative studies approaching this issue. Being a binary trait, genetic parameters for SW can be estimated considering continuous or categorical data under frequentist and Bayesian methods providing support for the selection and mating of animals in breeding programs. Therefore, the objectives in this study were to obtain and compare the variance component estimates for preweaning calf survival of calves in single-trait analyses and their correlations with a continuous trait in two-trait analyses. An amount of 25 218 data of the categorical trait of calf survival until weaning (SW) and the continuous trait of weaning weight (WW) were collected between the years of 2000 and 2012 in six herds of Nellore cattle. Methods III of Henderson, Maximum Restricted Likelihood (REML), Bayesian Inference and Generalized Linear Mixed Model (GLMM) were tested. Variance components obtained in one-trait analyses were similar to those obtained in two-trait analyses. Estimates of heritability (h2) obtained with different models for SW ranged from 0.0206 to 0.2644. The comparison between different estimation methods in single or two-trait analysis models allows the conclusion that the most appropriate method for SW analysis was the Bayesian estimation under an animal model and assuming linear distribution for phenotypes of SW trait.

Radiotelemetry methods were used to examine the demographic characteristics of sea otters inhabiting the leading edge of an expanding population on Kodiak Island, Alaska. Fifteen male and 30 female sea otters were instrumented and followed from 1986 to 1990. Twenty-one percent of females were sexually mature (had pupped) at age 2, 57% by age 3, 88% by age 4, and 100% by age 5. Fifteen females produced 26 pups, an overall reproduction rate of 94% for mature females. The reproduction rate was 17, 45, 66, and 100% for 2-, 3-, 4-, and 5-year-olds, respectively. Eighty-five percent of observed pups survived to weaning (120 days), and the percentage of pups weaned ranged from 34% for pups of 2-year-olds to 100% for pups of 5-year-olds. At least three of four known pup losses occurred within a month of parturition. The mean pup dependency period for weaned pups was 153 days and the mean gestation period was 218 days. No synchrony in pupping activity was observed. Mean annual survival of adults was high. Estimates of survival ranged from 89 to 96% for females and 86 to 91% for males. Human harvest was the primary source of known mortality of adults. Our estimates of reproductive rates and survival of adults are at the high end of those reported for sea otters, but preweaning survival stands out as being particularly high. Abundant food resources and the availability of protected water presumably contributed to the high reproductive success observed in this recently established sea otter population.

Abstract The objective was to evaluate factors associated with nursery throughput. Data consisted of 3,260 piglets from 320 litters at the NCDA Tidewater Research Station. At weaning, piglets were housed nine per pen (0.23m2 per pig) in onsite nursery facilities for 35 d. Using linear models, farrowing batch (BATCH), gender, litter size (LS), average piglet birth weight (BWT), birth weight CV (BWT_CV), piglet weaning weight (WWT), weaning weight CV (WWT_CV) and weaning age (WEANAGE) were associated with nursery average daily gain (NurADG), nursery exit weight (NurEXITWT), nursery survival (SURVIVAL) and full-value nursery pigs (FULLVALUE, pigs &gt;13.6kg at nursery exit). Litter was the experimental unit. Average WEANAGE, WWT, SURVIVAL and FULLVALUE were 28.1 (±4.7 d), 7.8kg, 98.7% and 94.3%, respectively. Correlations between NurADG with gender, LS, BWT, BWT_CV, WWT, WWT_CV and WEANAGE were zero, -0.04, 0.24, 0.09, 0.81, 0.10 and 0.73, respectively. Factors related (P &lt; .01) to NurADG included BATCH, BWT, WWT and WEANAGE (R2 = 0.80). Within these factors, WWT and WEANAGE explained 70% of the variation in NurADG. A 1kg increase in BWT and WWT increased (P &lt; 0.01) NurADG by 60.3 and 19.4g per pig per d, respectively. A 1 d older WEANAGE increased (P &lt; 0.01) NurADG by 9.36g per pig per d. Increased NurEXITWT was associated (P &lt; 0.05) with BATCH and greater BWT, WWT and WEANAGE (R2=0.88). Within these, WWT and WEANAGE explained 83% of the variation in NurEXITWT. A 1kg increase in BWT and WWT increased (P &lt; 0.01) NurEXITWT by 2.09 and 1.68kg per pig, respectively. A 1 d older WEANAGE increased (P &lt; 0.01) NurEXITWT by 323g per pig. Increased BWT was associated (P &lt; 0.01) with greater SURVIVAL, explaining 4% of the variation. Improved FULLVALUE was associated with (P &lt; 0.05) BATCH and generally greater BWT, WWT and WEANAGE (R2 = 0.44). Of the factors studied, WWT had the greatest impact on the percentage of FULLVALUE at nursery exit (R2 = 0.36).

Abstract Preweaning survival and growth are compromised in litters with larger numbers of piglets. We evaluated two approaches for altering initial nursing with the goal to improve access to colostrum by groups of piglets that are known to have reduced access to colostrum. Therefore, we temporarily (1.5 h) removed either the heaviest six piglets in the litter (WT) or the first half of the piglets born (ORD) to provide a short period of nursing with reduced competition for the remaining piglets. We found that WT piglets were heavier (P ≤ 0.05) at 7 d after farrowing and gained more body weight (BW) from farrowing to day 7 than control (CON) piglets which were raised in litters with ad libitum nursing during the same period. Further, we found that the heaviest piglets consumed more (P &lt; 0.001) colostrum and gained more (P &lt; 0.001) BW during the preweaning period but did not have (P &gt; 0.10) greater immunocrits. Although ORD piglets had similar colostrum intake, immunocrits, and preweaning weights as controls, we found that overall the piglets born in the first half of litters had greater (P &lt; 0.01) immunocrits than piglets born in the last half of the litter. Therefore, both birth weight and birth order have effects on traits that are important for prenatal growth and survival, but they differ in that birth weight is more closely related to colostrum intake and birth order affects immunocrit.

Orientador: Ana Fabrícia Braga Magalhães
Resumo: ABSTRACT – Preweaning calf mortality is one of main causes of economic losses in beef cattle, since most of economic incomes are represented by the number of weaned calves available for sale. It is also detrimental for genetic progress due to the reduction of young candidates for selection. The inclusion of molecular markers in genetic analysis allows a better understanding of genetic mechanisms underlying calf mortality. The objectives of this study were: i) to estimate direct and maternal heritability of preweaning calf mortality in Nellore cattle and ii) to seek for genomic regions and candidate genes affecting direct and maternal effects of preweaning calf mortality in Nellore cattle. Variance components were estimated via Bayesian Inference using a threshold animal model, that included the systematic effects of contemporary group, birth weight as linear covariate, and age of dam at calving as linear and quadratic covariates. The direct and maternal genetics, and the residual were fitted as random effects. The final dataset used contained phenotypic records on 67,196 animals, offspring of 1,469 sires and 30,970 dams. The SNPs effects were estimated based on the weighted single-step GBLUP approach, using information of 8,443 genotyped animals with 410,936 SNPs. Direct and maternal heritability estimates were of 0.2143±0.0348 and 0.0137±0.0066, respectively. The top 10 genomic regions accounted for 13.61 and 14.23% of direct and maternal additive genetic variance and harbor... (Resumo completo, clicar acesso eletrônico abaixo)
Mestre

Preweaning mortality is a major cost to the pork industry that, despite piglet management being a highly researched area, continues to increase. Low viability piglets are credited for a large percentage of this mortality, however, the terminology and measures used to identify these piglets is inconsistent. Therefore, we proposed to investigate existing and novel parameters to better identify these truly low viability piglets and potential management strategies for improved survival Chapter 2 briefly summarises the previous knowledge of what a viable piglet has been defined as, and current commonly used management strategies for their management. The main outcomes of this chapter were that identification lies in the early evaluation of the complex relationship between a piglet’s physical characteristics, temperature and colostrum intake. It also acknowledged the critical role of the sow in a piglets’ starting viability. Chapter 3 focused on piglet morphology and identified that rather than an individual trait, the proportion of crown to rump length and abdominal circumference are indicative of survival and performance. Chapter 4 focussed on sow transition phase feeding manipulation for increasing born alive and showed that with decreasing farrowing duration through increased feeding frequency the number of piglets born alive increased, suggesting higher litter viability at birth. Chapters 5 was an initial look into the temperature profile of piglets from birth to 24 h using rectal and surface temperature to determine if monitoring temperature change was a critical identifying factor. Repetitive rectal temperature measurements were deemed stressful and impractical for production application. Therefore, we investigated surface temperature further as, based on the findings from Chapter 5, it was highly variable at birth and 24 h, which are critical timepoints for interventions. Chapter 6 was a comparison of three surface locations; base of ear, tip of ear and eye to rectal temperature for correlation and practicality. We determined from the outcomes of Chapters 5 and 6 that temperature monitoring is an important indicator but, under production conditions, surface temperature is too unreliable for identifying at-risk piglets. Currently, temperature interventions are largely based around providing energy supplements which reduce available stomach volume for colostrum, and or external warming methods like heat lamps which are stationary and drying which has had short term temperature improvements. Chapter 7 introduced a warming method used in human surgeries to reduce risk of postoperative hypothermia. A warm saline bolus was injected into the intraperitoneal space of piglets, and this improved subsequent temperature and survival especially in low-birth-weight piglets. Collectively, the findings of this thesis present novel identification and management strategies for improved piglet survival and evaluate existing methods for production application. This research has enabled the stimulation of a change in perspectives of piglet management research, adding strength to the need to reanalyse how we identify low viability at-risk piglets for improved survival.
Thesis (Ph.D.) -- University of Adelaide, School of Animal and Veterinary Science, 2022

碩士
東海大學
畜產學研究所
84
Summary Two investigations were conducted to study: (1) the effect oforally dosed Medium-Chain Triglycerides (MCT) and carnitine onmilk consumption of neonatal pigs; (2) the effect and cause of MCTin sow diets during late gestation and lactation period on survivalof piglets. Investigation 1: Ten litters of 90 neonatal crossed piglets( Duroc × Landrace) were either dosed 6 mL MCT/kg(BW)~BS2;0.75 ~BS0;、6mL MCTplus 100 μmole carnitine/kg(BW)~BS2;0.75~BS0; by stomach tube (treatmentgroup) or mimicked dosing process (control group) at 8 h afterbirth. The subsequent milk consumption during 8 h after dosingwere determined hourly by weigh-suckle-weigh procedure. Resultsindicated that MCT reduced milk consumption (P<0.05) of pigletsduring first 3-h period after dosing; carnitine improved (P<0.05)milk consumption for first 3-h period, but still was lower( P<0.05) than the milk consumption of piglets in control group.Dosed MCT or carnitine did not affect milk consumption of pigletsin other time period, except a higher milk consumption in 7th hwas observed in piglets in MCT group than piglets in MCT pluscarnitine group (P<0.05). Investigation 2: Experiment 1, beginning at d 84 of pregnancy,51 sows were allotted to one of three treatments and were fedcorn-soybean diets containing 10% of (1) soybean oil, (2) coconutoil or (3) MCT (n=17, 18, 16, respectively). Sows were fed 2 kg/duntil d 100 of pregnancy and were increased 2.4 kg/d untilfarrowing then were fed to appetite during 28-d lactation period.Feed intake, lactation weight loss and weaning-to-estrus intervalof sows were not affected by treatment (P>0.05). A lower fat andgross energy but not protein content in colostrum (or milk) ofsows fed MCT than of sows fed soybean oil or coconut oil wasobserved (P<0.05). Litter performance of sows were not affected bytreatment, except a higher litter weight and preweaning survivalwere found in sows fed MCT or coconut oil. Sows fed MCT (P<0.05)or coconut oil (P<0.11) had larger weaning litter weight than sowsfed soybean oil had. Preweaning survival of pigs was improved inlitters from sows fed MCT (P<0.01) or coconut oil (P<0.10) thanlitters from sows fed soybean oil, such improvement was observedmajorly at first 3 d after birth, especially in pigs weighed <1100g at birth; their survival were 38.1, 70.0 and 91.6 % in soybeanoil, coconut oil and MCT groups, respectively. Experiment 2, beginning at d 84 of pregnancy, 24 sows wereassigned randomly to three dietary treatmemnts with eight sowseach treatment and were fed diets until farrowing. The dietarytreatments were as the same as experiment 1. Results showed thatsows fed MCT had a four-fold increase in plasma β -hydroxy-butyrate (P<0.05); sows fed coconut oil had a two-fold non-significant increase in plasma β -hydroxybutyrate (P>0.05).Piglets farrowed from sows fed coconut oil had higher liver(P<0.05) and muscle (P<0.10) glycogen, and piglets farrowed fromsows fed MCT had higher liver (P<0.10) and muscle (P<0.01)glycogen and plasma glucose level at birth (P<0.05) than thosefarrowed from sows fed soybean oil had. Body dry matter and fatcontents of piglets at birth were not affected by treatment(P>0.05), but piglets farrowed from sows fed MCT had highercarcass protein (P<0.05) than those farrowed from sows fed soybeanoil had. Piglets farrowed from sows fed coconut oil had a lowerblood fructose (P<0.10) and a higher plasma albumin contents(P<0.01), and piglets farrowed from sows fed MCT had a lower bloodfructose (P<0.01) and a higher plasma albumin contents (P<0.01)than those farrowed from sows fed soybean oil had. In summary, orally dosed MCT decreased milk consumption ofpiglets during first 3-h period after dosing and carnitinepartially alleviated this adverse effect. Supplementing MCT orcoconut oil to gestating sow diet improved piglet survival andweaning litter weight while maintaining a normal weaning to estrusinterval of sows. The improved piglet survival probably was causedby MCT or coconut oil improved energy status (ie. higher bodyglycogen) and maturity (ie. lower blood fructose and higher plasmaalbumin contents) of piglets at birth.

This chapter demonstrates that youngstock management can play a critical role in optimising dairy herd health. While the immediate impact of better calf management is visible to farmers in better youngstock health and growth, the long-term benefits in dairy herd productivity and survival need to be emphasised more by veterinarians and agricultural advisers. The most consistently reported management factors associated with reduced age at first calving (AFC), higher milk production and longer survival were feeding a larger volume of colostrum, offering a higher liquid feed volume preweaning, offering a higher solids milk replacer, offering whole milk and a higher average daily gain. The three health disorders most frequently associated with increased AFC, lower milk production and shorter survival were dystocia, calf diarrhoea and respiratory disease. These results have implications for producer perception and management of calfhood nutrition and health hazards and veterinary communication on calfhood disease sequelae with lag dynamics.