Post-weaning Stage Research Articles

Fecal Microbiota Succession of Piglets from Birth to Post-weaning by 454 Pyrosequencing Analysis

The objective of this study was to describe the fecal microbiota succession of piglets from birth to post-weaning by pyrosequencing. The dominant bacterial phyla were Bacteroidetes, Firmicutes, Proteobacteria, and Fusobacteria, although the composition of the fecal microbiota changed as the piglets grew. Bacteroides, Parabacteroides, Prevotella, Lactobacillus, unclassified Lachnospiraceae, Ruminococcus, Oscillospira, Phascolarctobacterium, and Desulfovibrio were the core genera in the feces of piglets and existed from birth to post-weaning. Bacteroides was the most abundant at birth; however, the proportion of Bacteroides decreased as the piglets aged, while the proportion of Prevotella increased until it became the most abundant genus at the post-weaning stage. Principal coordinate analysis indicated that the microbial communities of piglet fecal samples from birth to post-weaning could be separated into four groups according to the similarity of community composition. These corresponded to time points on day 0 (birth); day 7; days 14, 21, and 28 (pre-weaning); and day 35 (post-weaning). This study suggests that the development of the intestinal microbiota in the piglet is a gradual and sequential process. This methodology establishes a basis for broader studies to investigate the microbiota of the piglet intestinal tract.

Selection Practices of Bonga Sheep Reared in Southern Ethiopia

The study was conducted to assess the traits traditionally used to select the Bonga sheep reared in Southern Ethiopia. The breed was included for improvement under the community based breeding program (CBBP) launched in the year 2009. The results are based on the data collected from the project between 2009 till 2012. The findings are based on focus group discussions with the community elders who have been rearing the Bonga sheep for more than 20 years. The present findings are based on information obtained from 50% of the total respondents who were involved in CBBP. The Bonga sheep is a mutton type breed and the ewes are moderately prolific. In the past this breed of sheep were bartered to settle legal disputes and were traded against household commodities.. However, over the years (and also after the intervention of CBBP) the sheep have been selected for their body weight as well as for their distribution in many parts of Ethiopia The respondents selected the lambs at both pre weaning and post weaning stages. Traditionally the traits of rams are selected based on their body length, canon circumference, broad face, enlarged thyroid, while for the ewes, traits prolificacy, skin thickness and pelvic width are determining characters. Fat tail and brown coat color were preferred irrespective of the sexes in trait selection. The ram lambs selected for breeding purpose are locally known as “Dookoo”. These rams are selected based on some predetermined phenotypic traits and are initially selected at preweaning stage and further, again at the post weaning stage. These rams are preferentially cared and are provided with supplementary feed and comfortable housing.

Replacement of Concentrate Mixture with Dried Azolla on Milk Yield and Quality in Barbari Does

Twelve Barbari goats in 2-3rd lactation at post weaning stage were fed with complete pellet (control and treatment) for 6 wks using CRD with six does per treatment. Control pellet was having gram straw and concentrate mixture in 60: 40 while in treatment pellet a part of concentrate was replaced with sundried azolla. Digestion trial was conducted after 4 wks of experimental feeding. Blood and rumen fluid was collected at the end of experimental feeding. Daily feed intake and milk production was recorded. The digestibility of dry matter and organic matter was statistically similar in control (60.67 and 62.63) and treatment group (54.07 and 56.48) of goats. The digestibility of other nutrients was also statistically similar for both the group of goats. Ruminal pH, TVFA and various nitrogenous fractions (Ammonia-N, Total-N, TCA-ppt N and Non protein-N) were similar in control and treatment group of lactating goats. Serum protein and their fractions were within normal range in both the group of lactating goats. The feed intake was statistically similar in both the group. The average milk production (ml/day) in treatment group (490.78) was 19.87% more as compared to control group of goats (409.43) during experimental feeding. The different milk constituents like fat, SNF, protein lactose were also similar in both the group. Present study concluded that sundried azolla meal can be incorporated in the ration of lactating goat.

Effect of feed type and method of presentation on feeding behavior, intake, and growth of dairy calves fed a high level of milk

The objective of this study was to assess the effect of different feed types and method of feed presentation in the first 12 wk of life on the feeding behavior, intake, and growth of calves fed a high milk level. Forty-eight neonatal Holstein calves were individually housed and randomly assigned to 1 of 4 treatments and fed solid feed ad libitum: silage-based total mixed ration (TMR), concentrate (CON), and chopped hay and concentrate presented in 2 manners: mixed (MIX) or separate (SEP). All calves were offered 12 L/d of acidified milk replacer (1.8kg of dry matter) until d 38 at which time step-down weaning by 1 L/d began. At d 50 calves no longer received milk, and all calves on SEP and CON treatments were offered the MIX diet until the end of the trial, whereas TMR and MIX calves did not change feeds. Feed intakes were recorded daily, and calves were weighed twice per week. Rumination time was observed on the last 3 d of alternate weeks (wk 3, 5, 7, 9, and 11) for 1h beginning at 1500h. Time spent feeding was determined for the last 2 d of alternate weeks. In the preweaning stage (d 1–37) average daily gain was similar for all calves (1.1kg/d). The TMR calves had lower average daily gain than calves on the other 3 treatments during both the weaning (d 38–49; 0.2 vs. 0.7kg/d) and postweaning (d 50–84; 0.5 vs. 1.2kg/d) stages. This result is related to the lower dry matter intake of calves fed TMR in comparison with MIX, SEP, and CON calves in the weaning (0.2 vs. 0.5kg/d) and postweaning (1.8 vs. 2.8kg/d) stages. Given dry matter content of the feeds (TMR=52%, other diets=89%), the as-fed intake of the calves was similar across treatments in all 3 stages. Calves offered hay in addition to concentrate showed no difference in concentrate intake in the first 7 wk of life. Interestingly, TMR calves spent more time feeding during the postweaning stage than MIX, SEP, and CON calves (308 vs. 194min/d) and exhibited a slower feeding rate postweaning (5.9 vs. 14.4g of dry matter per minute). It appears that during weaning, and postweaning, calves fed TMR were attempting to maximize their nutrient intake but were unable to match that of calves in other treatments because of the high moisture content of their feed, and thus were unable to achieve similar average daily gain. Additionally, growth and total intake throughout the preweaning and weaning stages were similar for calves fed chopped hay along with concentrate and those not offered hay, suggesting no detrimental effect of feeding forage.

Principal Component Analysis of Conformation and Blood Marker Traits at Pre- and Post-Weaning Stages of Growth in F2 Crossbred Nigerian Indigenous X Landrace Pigs

Linear body measurements and blood hematology and biochemistry parameters were taken on 92 and 15 grower pigs, respectively, chosen randomly from a crossbred F2 population of Nigerian Indigenous (NI) x Landrace pigs to evaluate body conformation and blood marker traits using a multivariate approach. For linear body measurements at pre-weaning stage (4 weeks old), two principal components accounted for 91.63% of the total variation in body conformation traits, while at post weaning stage (12 weeks old), one principal component accounted for 73.63% of the total variations in body conformation traits. The first factor (principal component) accounted for 72.34% of the total variance (body weight) while the second factor accounted for 19.29% (ear length) at pre-weaning stage. While at post-weaning stage only one factor contributed to the total variability of the original six traits tested, with 73.63% (body length). For blood parameters, three principal components accounted for 81.85% of the total variation at pre-weaning stage while 89.44% of the total variation at post-weaning stage was accounted for by four principal components. The first factor (principal component) accounted for 38.048% (Packed cell volume), the second accounted for 24.72% (hemoglobin) and the third accounted for 19.08% (aspartate transaminase). While at the post-weaning stage, the first factor was influenced by red blood corpuscles (37.17%), the second factor had its loading for hemoglobin (25.80%), the third factor had loading for white blood corpuscles (13.67%), while the fourth factor had loading for alkaline phosphatase only (12.80%). Using communality extraction factors, ear length best described body conformation at the pre-weaning stage; whereas, at post-weaning stage, body length was the best descriptor. In blood parameters, packed cell volume best described blood marker traits at the pre-weaning stage; whereas, at the post-weaning stage, red blood corpuscles best described it. Hence, the two extracted factors in linear body measurements and in blood parameters could be considered in breeding programs to improve and predict body conformation in crossbred pigs, as well as predict blood marker traits.

Evaluación de tres dosis de un preparado microbiano, obtenido en Ecuador, en la respuesta productiva y sanitaria de cerdos en posdestete

<p>Para evaluar tres dosis de un preparado microbiano obtenido en el Ecuador (4x106 UFC de bacterias lácticas, 1,5x105 UFC de levaduras por cada mililitro), en el comportamiento productivo y de salud en cerdos durante la etapa post-destete, se aplicó un diseño completamente aleatorizado, con cuatro tratamientos y cuatro repeticiones por tratamiento: T1 concentrado, T2, T3, T4 (concentrado más 5 mL/kg de peso vivo (PV), 10 mL/kg PV 15 mL/kg PV del preparado microbiano, respectivamente). Se utilizaron 160 cerdos castrados del cruce Landrace x Large White con Blanco Belga x Pietrain, de 28 d de edad y con 6,99 kg de PV. El mayor peso vivo final y la mejor ganancia de peso total y diaria (P < 0,0001) se obtuvo en el grupo de cerdos donde se agregó 15 mL/kg PV del preparado microbiano, con valores de 25,78 kg, 18,78 kg y 447,25 g, respectivamente. En el mismo grupo experimental se encontraron las conversiones de materia seca, proteína bruta y energía metabolizable más eficientes 1,54 kg /kg PV y aumento de peso vivo de 383,92 g/kg PV y 23,16 MJ/kg PV, respectivamente. También en este grupo se registró la menor presencia de animales con diarrea (P < 0,0001) 6,85%. Se concluye que la adición de 15 mL/kg PV mejora el comportamiento productivo y sanitario de cerditos destetados.</p>

Low-intensity and moderate exercise training improves autonomic nervous system activity imbalanced by postnatal early overfeeding in rats.

BackgroundPostnatal early overfeeding and physical inactivity are serious risk factors for obesity. Physical activity enhances energy expenditure and consumes fat stocks, thereby decreasing body weight (bw). This study aimed to examine whether low-intensity and moderate exercise training in different post-weaning stages of life is capable of modulating the autonomic nervous system (ANS) activity and inhibiting perinatal overfeeding-induced obesity in rats.MethodsThe obesity-promoting regimen was begun two days after birth when the litter size was adjusted to 3 pups (small litter, SL) or to 9 pups (normal litter, NL). The rats were organized into exercised groups as follows: from weaning until 90-day-old, from weaning until 50-day-old, or from 60- until 90-days-old. All experimental procedures were performed just one day after the exercise training protocol.ResultsThe SL-no-exercised (SL-N-EXE) group exhibited excess weight and increased fat accumulation. We also observed fasting hyperglycemia and glucose intolerance in these rats. In addition, the SL-N-EXE group exhibited an increase in the vagus nerve firing rate, whereas the firing of the greater splanchnic nerve was not altered. Independent of the timing of exercise and the age of the rats, exercise training was able to significantly blocks obesity onset in the SL rats; even SL animals whose exercise training was stopped at the end of puberty, exhibited resistance to obesity progression. Fasting glycemia was maintained normal in all SL rats that underwent the exercise training, independent of the period. These results demonstrate that moderate exercise, regardless of the time of onset, is capable on improve the vagus nerves imbalanced tonus and blocks the onset of early overfeeding-induced obesity.ConclusionsLow-intensity and moderate exercise training can promote the maintenance of glucose homeostasis, reduces the large fat pad stores associated to improvement of the ANS activity in adult rats that were obesity-programmed by early overfeeding.

Productive performance of Brangus cattle at weaning in grazing conditions in Colombia

<p>The aim of this study was to evaluate and compare the performance of Brangus calves at weaning under grazing conditions, and determine the influence of the sex on its performance. This study was conducted in the Cartago municipality (Colombia), in a herd dedicated to the production of beef with Brangus breed. The data were analyzed by ANOVA with a 95% significance using the statistical software InfoStat 2015. Full records of second lactation cows that were served by the same bull were evaluated to reduce the error factor. The variables evaluated were: weight at birth, weight at weaning, meat production index and average daily gain (ADG). The following model of age at weaning was considered as a covariate: Yij=u+Ti+BXij+Eij. The weight at birth was 33.22±1.86 and 31.88±0.89 kg for males and females respectively, weight at weaning was 246.00±51.69 and 225.81±21.78 kg respectively, rate of production was 0.64±0.12 and 0.62±0.05% respectively, ADG was 890±280; 850±100 grams/day respectively, and age at weaning of 251.78±44.01 and 228.19±16.30 days respectively. Only statistical significant difference for weight at birth (p=0.0286) was observed. In conclusion, both males and females Brangus showed differences in birth weight; however, differences in meat production levels are not significant since these reach at weaning similar weight, meat production index and average weight gain. In this sense, the productive trend may be similar at post-weaning stage, being feasible to employ both males and females interchangeably for the production of beef; additionally, the heifers can arrive faster at age for bull service.</p>

Dynamic changes in TAP1 expression levels in newborn to weaning piglets, and its association with Escherichia coli F18 resistance

The transporter associated with antigen processing (TAP) transports peptides from the cytosol into the endoplasmic reticulum for subsequent loading onto the major histocompatibility complex (MHC) class I molecules. This study showed the dynamic changes in the TAP1 expression level in newborn to weaning piglets. Tissue expression profiles revealed that the TAP1 gene was expressed at low levels in all tissues, and the expression levels were relatively higher in the lung, spleen, lymph, and thymus; further, no significant difference was observed in the expression in each tissue among the 3 unweaned stages (8, 18, and 30 days). Nevertheless, the postweaning (35 days) expression levels in tissues, including the spleen, lung, lymph, duodenum, and jejunum were significantly higher than those in the unweaned stages. Furthermore, gene ontology and pathway analysis showed that TAP1 took part in 38 biological functions and 5 pathway processes, including ABC transporters and antigen processing and presentation. These analyses showed that the TAP1 gene, which was related to MHC I immune regulation, had a stable and low expression level in unweaned stages; however, its expression increased in the postweaning stages. The high expression level of TAP1 indicated that the gene might play an important role in Escherichia coli F18 resistance.

Effect of Protein and Mineral Improvement on the Performance of Growers Goats

The current trials were initiated to help the goat keepers improve the nutritional status of grower goats with other alternative supplements offered by available cotton and mucuna seeds and locally made mineral lick. The performances of the growers such as growth rate of 12 months, weight at one year and mortality rate at postweaning stage of 3 to 12 months were measured. The results showed that treatment effect on dry matter intake by growers was significant. The growers fed the seeds consumed significantly more dry matter than those fed sole palm frond. Treatment effect on digestible dry matter intake was highly significant. The mean digestible dry matter intake by growers in the period of 8 to 12 months ranged between 25.8 g in the control and 39.1 g/kg 0.75 /day in the mucuna seed without salt lick group. Treatment effect was highly significant. The growers fed diets supplemented with the seeds showed higher growth rate than those in the control. The growers fed diets supplemented with the seeds showed higher weight at one year compared to the control. The mean weight at one year varied from 12.0 kg in the growers fed the seed to 14.6 kg in treatments with mineral lick. Use of these sources of protein could help the household in providing feed for their goats especially in the dry season and also in increasing the size of household flocks.

Selfish mothers? An empirical test of parent-offspring conflict over extended parental care

Parent-offspring conflict (POC) theory is an interesting conceptual framework for understanding the dynamics of parental care. However, this theory is not easy to test empirically, as exact measures of parental investment in an experimental set-up are difficult to obtain. We have used free-ranging dogs Canis familiaris in India, to study POC in the context of extended parental care. We observed females and their pups in their natural habitat for the mother's tendency to share food given by humans with her pups in the weaning and post-weaning stages. Since these dogs are scavengers, and depend largely on human provided food for their sustenance, voluntary sharing of food by the mother with her pups is a good surrogate for extended parental care. Our behavioural observations convincingly demonstrate an increase of conflict and decrease of cooperation by the mother with her offspring over given food within a span of 4–6 weeks. We also demonstrate that the competition among the pups in a litter scales with litter size, an indicator of sib–sib competition.

Kitten nutrition

ABSTRACT:The evolution of the cat – from opportunistic rodent-eating hunter to indoor companion with ready access to meals – has coincided with an increased lifespan and health. However, the cat remains unique in many of its dietary needs and in the way it generates energy, with specific requirements for certain nutrients. Its carnivorous metabolism, reinforced by historical access to a diet of animal-based tissues and very little carbohydrate, have meant that some of its enzyme systems are limited in their capacity – or lacking altogether. This has led to an absolute need for certain essential nutrients from animal flesh in the food and supplementation with others. The growth life-stage phase sees some further requirements, with an increased need for energy and protein, along with certain nutrients. Many commercial diets now provide an easy-to-feed, balanced way of providing these essential nutrients to take the kitten from a vulnerable post-weaning stage through to a healthy adult.

Enhanced Behavioral Response to Serotonin-Related Agonists in Postweaning Protein Malnourished Mice

We investigated whether postweaning protein malnutrition (PM) affects serotonergic systems. Mice were fed a PM diet or normal protein (control) diet from weaning (21 d of age). Twenty days later, we tested for behavioral effects of the selective serotonin (5-HT)(1A) receptor agonist 8-hydroxy-N,N-dipropyl-2-aminoteralin (8-OH-DPAT) and the 5-HT releaser d-fenfluramine. The number of head weaving responses induced by 8-OH-DPAT or d-fenfluramine in the PM mice was significantly increased compared with the control diet group. The effects of 8-OH-DPAT and d-fenfluramine were blocked by pretreatment with the selective 5-HT(1A) receptor antagonist WAY-100635 (0.01 mg/kg). However, postpubertal (56 d of age) mice fed with the PM diet did not show an enhancement of the 8-OH-DPAT-induced head weaving response. These results indicate the occurence of a supersensitivity of postsynaptic 5-HT(1A) receptor in the postweaning PM group. Moreover, they highlight the postweaning stage as a vulnerable period to malnutrition-induced alterations in central serotonergic systems.

Frequency of species of Eimeria in females of the holstein-friesian breed at the post-weaning stage during autumn and winter

The frequency of species of the genus Eimeria in a dairy herd in the municipality of Boa Esperança, Southern region of the State of Minas Gerais was assessed. From 37 females of the Friesian breed aged three to seven months, 259 feces samples were analyzed between May and September 2008. The examinations to quantify oocysts per gram of feces (OPG) and identify Eimeria species were conducted at the Veterinary Parasitology Laboratory of the Federal University of Lavras. Eleven species of Eimeria were identified, namely: E. bovis (23.2%), E. zuernii (22.6%), E. ellipsoidalis (20.3%), E. cylindrica (14.1%), E. subspherica (5.4%), E. canadensis (3.5%), E. alabamensis (2.4%), E. auburnensis (2.4%), E. pellita (2.1%), E. brasiliensis (2%) and E. bukidnonensis (1.9%). E. bovis, E. zuernii and E. ellipsoidalis were the most frequent and the ones with the highest oocyst shedding over time (p < 0.05). Differences in OPG counts were found between most months studied (p < 0.05). The large number of Eimeria species found, in particular E. bovis and E. zuernii, indicates that Eimeria sp. has significant pathogenic potential in dairy cattle in the South of Minas Gerais.

A comparison of subcutaneous adipose tissue proteomes in juvenile piglets with a contrasted adiposity underscored similarities with human obesity

Subcutaneous fat tissues from an indigenous fat-type breed and an intensively-lean selected breed were studied in juvenile pigs. Combining DIGE with bioinformatics and target analyses of key genes, enzymes or terminal routes, this study identifies metabolic and homeostatic processes, response to organic substances, and acute-phase responses as the main pathways whose proteins were regulated in association with adiposity. Breed-related differences in abundance and activities of malic enzyme and glucose-6-phosphate dehydrogenase NADPH-supplying enzymes suggested up-regulation of the lipogenic pathway to dispose for a greater adiposity. Over-abundance in the lipolytic protein carboxylesterase-1 was revealed in fat-type piglets. A panel of pro- and anti-inflammatory proteins such as serpins, had an altered abundance in the fat-type piglets, suggesting adverse consequences of fat accumulation even in early post-weaning stages. Propensity to low-grade inflammation in fat pigs was reinforced by the up-regulation of genes encoding pro-inflammatory cytokines IL6 and TNF-α in these piglets. Differential abundance in annexin-A5 and pericentrin suggested a positive regulation of cell apoptosis in lean piglets. Our results are relevant in the context of data linking the accretion of body lipids to the physiology and pathology of adipose tissue in models other than rodents for a better control of human health and nutrition.

Effect of early feed type exposure on diet-selection behavior of dairy calves

Dairy cattle exhibit characteristic feeding behavior patterns that may be influenced by early experiences. The objective of this study was to determine how early exposure to different feed types affects diet selection behavior of dairy calves once fed a mixed ration after weaning off milk. Eight Holstein bull calves were randomly assigned at birth to a feed exposure treatment: concentrate or grass/alfalfa hay, offered ad libitum. All calves were offered 8L/d of milk replacer [1.2kg of dry matter (DM)] from birth, which was incrementally reduced after 4 wk to enable weaning by the end of wk 7. After milk weaning, all calves were fed a mixed ration containing (on a DM basis) 60% concentrate and 40% grass/alfalfa hay for 9 wk. Intake was recorded daily, and calves were weighed 3 times/wk. Samples of fresh feed and orts were taken in wk 8, 12, and 16 for particle size analysis. The separator had 3 screens (19, 8, and 1.18mm) producing long, medium, short, and fine particle fractions. Sorting of each fraction was calculated as actual intake as a percentage of predicted intake. Calves exposed to concentrate tended to have greater DM intake than calves exposed to hay both before (0.49 vs. 0.16kg/d) and after weaning off milk (3.3 vs. 2.6kg/d). Weights were similar during the milk-feeding stage, but calves exposed to concentrate had greater weights overall in the postweaning stage (129.8 vs. 112.6kg). Initially after weaning, calves sorted for familiar feed; calves previously exposed to concentrate sorted for short particles (126.4%), which were primarily concentrate, whereas calves previously exposed to hay did not (94.2%). Calves previously exposed to hay tended to sort for long particles (113.4%), which were solely hay, whereas calves previously exposed to concentrate sorted against them (56.4%). The sorting observed for short particles was associated with consuming a diet with a greater concentration of protein, nonfiber carbohydrates, and metabolizable energy, whereas sorting for long particles was associated with consuming a diet with a greater concentration of neutral detergent fiber. After 4 wk of exposure to the mixed ration, sorting was similar between treatments, with calves in both treatment groups sorting for short (117.4 and 120.5%) and against long (62.4 and 54.4%) particles, and consuming a diet with a similar concentration of nutrients and energy. These results indicate that feed familiarity affected initial diet selection postweaning, but may not have a lasting effect, with all calves developing similar feed-sorting patterns.

Genetic parameters for direct and maternal effects on post-weaning body measurements of Muzaffarnagari sheep in India

Variance components and genetic parameters were estimated for post-weaning (i.e., at 6, 9, and 12 months of age) body measurements in Muzaffarnagari sheep maintained at the Central Institute for Research on Goats, Makhdoom, Mathura, India over a period of 29 years (1976 through 2004). Records of 2,965 lambs descended from 162 rams and 1,213 ewes were used in the study. Analyses were carried out by REML fitting an animal model and ignoring or including maternal genetic or permanent environmental effects. Six different animal models were fitted for all traits. The best model was chosen after testing the improvement of the log-likelihood values. Direct heritability estimates were inflated substantially for all traits when maternal effects were ignored. Moderate estimates of direct heritability for body length (0.11-0.15), height at withers (0.14-0.19), and heart girth (0.14-0.24) of lambs were observed at post-weaning stages of growth. Results suggest that only direct additive genetic effects were important for body measurements at post-weaning stages of growth, and hence, modest rates of genetic progress were possible for post-weaning body measurements.

Maternal stress induces long-lasting Purkinje cell developmental impairments in mouse offspring

A number of clinical studies suggest that prenatal stress can be a risk factor in the development of various psychopathologies, including schizophrenia, depression, anxiety, and autism. The cerebellar vermis has been shown to be involved in most of these disorders. In the present study, therefore, we evaluate the effect of maternal stress on long-term alterations in vermal Purkinje cell morphology. Furthermore, to discern whether these structural changes are associated with anxious behavior, the exploratory drive in the elevated plus maze was evaluated. Pregnant CF-1 mice were randomly assigned to control (n = 14) or stressed (n = 16) groups. Dams of the stressed group were subjected to restraint stress between gestational days 14 and 20, while control pregnant dams remained undisturbed in their home cages. Anxious behavior and Purkinje cell morphology were evaluated in three ontogenetic stages: postweaning, adolescence, and adulthood. Although exploratory behavior in the elevated plus maze was unaffected by prenatal stress, the Purkinje cell morphology showed a transient period of abnormal growth (at postweaning and juvenile stages) followed by dramatic dendritic atrophy in adulthood. In conclusion, prenatal stress induced significant long-lasting bimodal changes in the morphology of vermal Purkinje cells. These structural alterations, however, were not accompanied by anxious behaviors in the elevated plus maze.

Cranial ontogeny ofCaluromys philander(Didelphidae: Caluromyinae): a qualitative and quantitative approach

The ontogeny of skull allometry has been the subject of research in didelphid, microbiotheriid, and dasyurid marsupials. We described and compared postweaning stages of cranial development in the woolly opossum Caluromys philander, a member of a distinct lineage of didelphids. We identified 31 qualitative morphological changes between juveniles and adults, many related to the trophic apparatus. Early development of the paracanine fossa in the snout, correlated with the presence of well-developed canines in juveniles, represents a remarkable difference between the ontogeny of C. philander and other marsupials. We performed bivariate and multivariate analyses of allometry on a data set composed of 14 cranial measurements and 45 specimens. Allometric scaling showed that braincase is relatively small in adulthood, whereas other neurocranial components, particularly the orbit, grew isometrically along its length. The palate becomes elongated by the combination of the isometry of its length and the negative allometry of its width. The rostrum lengthened, but its height remained proportionally constant. In relative terms the temporal fossa expanded inward following the marsupial model that combines the negative allometry of the braincase and the isometry of the zygomatic breadth. The mandible increased in robustness. The skull ontogeny of C. philander shares 4 allometric trends with 2 didelphids (Didelphis albiventris and Lutreolina crassicaudata) and two australidelphians (Dromiciops gliroides and Dasyurus albopunctatus). Three of these trends, breadth of palate, breadth of braincase, and height of occipital plate, were allometrically negative, whereas height of the dentary was positive. These common allometric trends may be interpreted as symplesiomorphic for marsupials, suggesting a high degree of conservatism in the skull development of Caluromys and other marsupials. DOI: 10.1644/09-MAMM-A-291.1.

Effect of Different Feed Additives on Growth Performance and Blood Profiles of Korean Hanwoo Calves

This experiment was conducted on 60 Hanwoo calves comprising five feed additive groups, with 12 calves in each group, to determine the effects of additives at pre- and post-weaning on growth performance and blood profile. The groups were control, antibiotic (Neomycin 110 ppm), illite (2%), fermented green tea probiotics (FGTP, 0.5%), and mixed additives (FGTP 0.25%, illite 1% and licorice 0.1%). The calves were offered expecimental pellet feeds ad libitum and after one month were supplied with imported timothy hay. They moved freely within the group and suckled their mother's milk during the pre-weaning stage (birth to 3 months) and were separated from their dam during the post-weaning stage (4-5 months). During the pre-weaning stage, the highest average daily gain (ADG) was recorded in the antibiotic- and mixed additive-fed groups followed by FGTP, control and illite groups. In the post-weaning stage, significantly higher total weight gain and ADG were recorded in both the FGTP and mixed additive groups compared to the other groups (p 0.05), although hemoglobin and hematocrit values were lower in FGTP compared to control, but similar in mixed additive and antibiotic groups. These results indicate no detrimental effects of feed additives on the blood profile of calves at both pre- and post-weaning age. Serum albumin in post-weaning calves of all feed additive groups were similar but significantly lower (p<0.05) than in the control group. Post-weaning, IgM was significantly lower (p<0.05) in illite-fed calves compared to other treatment groups, but there was no difference at pre-weaning. Considering all factors, the mixed feed additives and FGTP can be the replacement feed formula for antibiotic for Hanwoo beef calf production, especially when used post- weaning.