Two trials were conducted to determine the effects of progesterone administered by controlled intravaginal drug release devices (CIDRs) on pregnancy rates and serum progesterone concentrations in heat stressed dairy cows. Trial 1 utilized a CIDR from days 5 through 12 after breeding, and trial 2 utilized a CIDR from days 5 through 19 after breeding. Rectal temperatures and blood samples were obtained from cows every other day throughout the trial. Serum progesterone concentrations were measured with radioimmunoassay (RIA). Pregnancy status was determined on approximately day 30 via transrectal ultrasonography. Mean temperature-humidity index (THI) values were 73.5 for trial 1 and 75.1 for trial 2. These THI values indicated that cows in both trials were subjected to mild heat stress conditions. No significant differences were found between CIDR treated and control cows in serum progesterone concentrations. In trial 1, pregnancy rates were 31.8% vs. 33.3% for control and CIDR treated cows, respectively (p = 0.25). In trial 2 pregnancy rates were 33.3% vs. 26.7% for control and CIDR treated cows, respectively (p = 0.29). In conclusion, supplemental progesterone administered to heat stressed dairy cows after breeding did not improve pregnancy rates or increase serum progesterone concentrations.

The objective was to examine the efficacy of saliva collection techniques and salivary cortisol assay to determine potential stress response in dairy heifers post challenge with adrenocorticotropin (ACTH) (Experiment 1), lactating cows without experimental stressors (Experiment 2), and gilt piglets versus boar piglets within two hours post castration stress (Experiment 3). Data were from the Holstein and Jersey dairy herd maintained by the Dairy Educational Unit at North Carolina State University and the crossbred swine herd maintained by the Swine Educational Unit also at North Carolina State University. In cattle (Experiments 1 & 2), saliva was collected using gauze squares secured by hemostats and introduced to each animalâs mouth until soaked. The same procedure was followed for the piglets (Experiment 3) with the addition of Sprite⢠to the gauze before introduction into the animalsâ mouth. Serum and saliva cortisol concentrations show a similar pattern after a stimulus to the adrenal gland with ACTH in Experiment 1. Salivary cortisol concentrations were lower than that found in serum and ranged from 27.40% to 59.94% of serum concentrations. In Experiment 2 the lack of an induced stress in lactating cows did not provide sufficient circulating cortisol for the sensitivity of the radioimmunoassay procedure utilized in this project. Data from these collections do illustrate the lack of a measureable stress response in animals from all three cow groups studied: Blood only, blood and saliva, or saliva only collection suggesting that neither sampling method elicits more stress response than the other. Sufficient saliva and circulating cortisol were obtained from the boar and gilt piglets in Experiment 3 to support our hypothesis that saliva is a viable tool for assessing stress in piglets. Mean concentrations for gilts were significantly lower than that of the castrated boars (1.36±0.301 versus 2.3074± 0.22 ng/mL).

Duckweed is the common name used to refer to members of the aquatic plant family Lemnaceae. Duckweed commonly grows on stagnant, nutrient enriched waters throughout tropical and temperate zones. Growth conditions include water temperatures of 6 ? 33^oC and a wide pH range. Under ideal conditions, duckweed can double its biomass every sixteen hours to four days. Its nutrient uptake capability helps to account for a CP of 15 ? 40% and high growth rate. Scientists have studied duckweed?s feed attributes for fish, poultry, swine, and ruminants. A duckweed feeding trial was carried out at North Carolina State University Metabolism Educational Unit with 19 goat wethers fed four different diets. The objective of the trial was to characterize the composition of wastewater grown duckweed and evaluate its use as a protein supplement for ruminants. Our hypothesis was that duckweed is a suitable protein source for goats and will behave in a similar fashion to soybean meal. The diets included a negative control, positive control (all of the supplemental protein from soybean meal), 1/3 duckweed, and 2/3 duckweed (1/3 and 2/3 of the supplemental protein came from duckweed, respectively). The goats were fed equal amounts of hay and supplement at 4% of body weight (as fed). Duckweed exhibited a similar compositional profile to soybean meal except for being lower in CP and higher in minerals. Amino acid and protein fraction profiles were also comparable between duckweed and soybean meal. There was no significant difference among treatments for DMI, ADF, and NDF digestibility. Nitrogen intake, N digested (g/d), and N retained (% of digested) showed no significant differences among the supplemental protein diets. Nitrogen retained as a percent of intake and N retained (g/d) tended to be slightly lower in the diets containing duckweed. Serum urea nitrogen levels also showed no significant differences for the protein diets except for a linear response (P = 0.09). The P balance showed no significant difference for P intake but both linear and quadratic responses for P retained (g/d), and P digested (g/d) as well as a linear response for P retained (% of digested). Similarities of the rumen pH, NH₄ and VFA data among the diets show that duckweed does not abnormally affect rumen function and is comparable to soybean meal in dietary function. Duckweed appears to be a viable source of protein and phosphorus (at lower dietary levels) supplementation for ruminants and is nearly comparable to soybean meal in its utilization.

A 2 x 2 factorial trial with 2 phases was conducted to evaluate the effects of weaning age (6 wk vs 12 wk) and anthelmintic treatment (non vs dewormed) on average daily weight gain (ADG) in 36 Holstein and Jersey X Holstein crossbred steers born in fall (Oct - Nov) and winter (Dec ? Feb) 2003 ? 2004. Steers were blocked into 4 treatment groups by birth weight and breed. Calves of similar age were managed together in pastures regardless of treatment and group-fed 3.8 to 7.6 L of whole milk/d until weaning. Phase 1 extended from birth until July 15, 2004. Phase 2 started on July 15 and ended on Nov 18, 2004. Dewormed calves received 1 mL ivermectin pour-on formulation/ 10 kg body weight (BW) at 12 and 20 wk of age, and again on July 15 and Sept 23. Fecal samples and BW (birth to Nov 18, 2004) were taken from each calf at 4-wk intervals. Fecal egg counts (FEC), BW, and ADG (during Phase 1, Phase 2, and Phases 1 & 2 combined) were compared among deworm, wean age, % Holstein, birth season, and their interactions. Parasite eggs were not detected until April and were lower in dewormed calves after July and Sept treatments. Fall-born calves usually had lower FEC than winter-born calves. Gains during Phase 1 were higher for fall-born calves. In Phase 2, dewormed calves actually had faster ADG than non-dewormed calves. Gain across Phase 1 and Phase 2 were higher in fall-born calves and tended to be higher in calves weaned at 6 wk. Gains and BW generally were higher with increasing % Holstein. Although steers that were not dewormed had higher FEC and differing ADG during parts of the trial, their overall performance was similar to those that received 4 doses of ivermectin.

Changes in metabolites and metabolic hormones during the first 12 weeks postpartum in both summer and winter were analyzed on a total of 18 lactating, Holstein cows (summer, n=11; winter, n=7). The summer trial covered the months of August through October. The winter trial began in November and lasted through early February. Maximum and minimum temperature and humidity values were recorded daily. Blood was sampled in serum, fluoride and heparin tubes from the coccygeal vein once a week beginning at day of calving for 12 weeks. Concentrations of progesterone, cortisol, thyroxine, leptin, NEFA, cholesterol and insulin were analyzed from serum samples. The metabolites glucose, PUN and â-HBA were analyzed with plasma collected from fluoride and heparin containing tubes. No significant seasonal differences were found between summer and winter calving groups for P4, T4, glucose, insulin, PUN and NEFA. However, leptin (P < 0.01), cholesterol (CHL) (P < 0.0001) and â-HBA (P < 0.0001) had significant seasonal differences between the two calving groups. The mild heat stress during the early part of the summer trial may not have been severe enough to detect significant changes in serum T4 or the animals had become acclimated to these temperatures. Summer calving cows may have experienced a drop in feed intake at calving (not measured) enough to increase their plasma ketone bodies (â-HBA), but not enough to dramatically reduce circulating levels of glucose and insulin.

The objective of this study was to characterize follistatin (FOL) as a candidate gene for litter size in pigs. Litter size is a lowly heritable and sex-limited trait; therefore, response to selection may be enhanced by marker-assisted selection. Our approach for characterizing a region of SSC16, which includes FOL, was to utilize the candidate gene approach using type I and type II markers to determine if FOL had an association with the response to selection for increased litter size in the select line. Pigs genotyped were from a line selected for increased number of fully formed (FF) pigs and a contemporary control line. In generation nine, the estimated breeding value for litter size was 0.63 pigs greater in the select line than in the control line (Holl et al., 2003). A RFLP within FOL (n = 251) and the microsatellites, CGT27 (n = 224), S0363 (n=255), S0298 (n=260), and SW1661 (n=253) were genotyped. Effect of marker genotype on FF, number born alive (BA), number still born (SB), and number mummified fetuses (MUM) was tested. Data were analyzed by line with an animal model using MTDFREML. Fixed effects included year and marker genotype. In both the select and control lines, all markers had no significant affect on FF, BA, SB, or MUM when using the animal model. Therefore, follistatin is not likely to have a major effect on litter size in the population studied.

Continued genetic improvement for milk production has been associated with decreased fertility in US Holstein cattle. A previous study (Ashwell et al., 2004) identified a putative quantitative trait locus (QTL) affecting daughter pregnancy rate at 54 cM on chromosome 18 in one Holstein grandsire family. The goal of this research is to determine the validity of the putative QTL using additional markers and an extended pedigree. Thirteen microsatellite markers located throughout the chromosome were genotyped in 973 animals that were descendants of the original grandsire in which the QTL was identified. Sons of the grandsire as well as six grandson and six great-grandson families of the original grandsire were selected for this study (range of 16 to 169 sons per family). In analysis of the sons using QTL Express, the same putative QTL affecting daughter pregnancy rate was detected and placed at 45 cM. In a joint analysis of thirteen of the largest families, each containing 10 or more sons, a significant QTL for daughter pregnancy rate was detected at 27 cM. QTL affecting daughter pregnancy rate was detected in two additional sub-families (Family II-5 and Family III-2), indicating a putative QTL affecting daughter pregnancy rate is most likely segregating within this pedigree. Across-family analysis also detected putative QTL on chromosome 18 affecting productive life at 35 cM, somatic cell score at 33 cM and percent difficult births at 72 cM. Analysis of individual families identified eight significant putative QTL and six suggestive putative QTL at the chromosome-wise level affecting somatic cell score, productive life, calving ease, percent difficult births, milk yield, fat yield, protein yield and fat percent. A complex pedigree analysis is underway to make full use of statistical power to refine the QTL region affecting fertility. Further verification of the QTL effects identified in this study will allow identification of positional candidate genes to be applied in marker assisted breeding programs.

Obesity is rapidly becoming a major problem in the United States and throughout the world. Polygenic models of obesity are most similar to human obesity because few humans are genetically obese due to a mutation in a single gene. Numerous studies have selected mice for body size and growth rate as models for selection of agriculturally important species. One series of selection experiments produced lines of mice having differing epididymal fat (EF) masses but similar body weights. These mice may be used as a model for adipose deposition without confounding the effects of body weight. One method of studying these mice is to examine gene expression. Expression of thousands of genes can be investigated at one time using microarrays. We used microarrays and real-time RT-PCR to compare gene expression between the high epididymal (HE) and low fat (LF) lines of mice, which have dissimilar EF mass but similar body weights. Microarray analysis identified 19 genes with differential expression between the HE and LF lines of mice with 5 of these genes differentially expressed in both liver and EF tissues. We found differential regulation of genes known to play a role in glucose uptake and lipid metabolism. In addition, we identified a differentially expressed gene, <I>solute carrier family 22 member 4</I>, located within the confidence interval of a quantitative trait loci associated with EF mass, making it a positional candidate. Furthermore, we identified a linked group of three genes (<I>Sortilin 1</I>, <I>guanine nucleotide binding protein alpha inhibiting 3</I>, and <I>selenium-binding protein 2</I>) on <I>Mus musculus</I> chromosome 3 (MMU3), which may represent a genomic ?hot spot? for genes associated with EF mass. In this study, differential expression of several genes not previously associated with obesity or adipose deposition were identified and may represent new targets for further research. Another aspect of obesity currently being investigated is anti-obesity compounds. One such compound is <I>trans</I>-10, <I>cis</I>-12-conjugated linoleic acid (CLA). CLA has been reported to reduce body weight and adipose mass in many species. Numerous studies have reported an increase in size, cytoplasmic vacuolization, and fatty acid synthesis in liver of CLA fed mice. The livers of CLA fed mice gain mass due to lipid accumulation; however, the precise molecular mechanisms are unknown. To elucidate these mechanisms, we examined the fatty acid composition, histology, and gene expression profile of liver from a polygenic obese line of mice fed CLA. Using a Periodic acid-Schiff stain, histological evidence suggests that glycogen content is unchanged in the liver of the CLA fed mouse implying that hepatic cytoplasmic vacuolization is due to increased lipid content. Microarray analysis identified 1393 genes differentially expressed at a nominal P-value of 0.01. Following Bonferroni correction and excluding lowly expressed transcripts, 198 genes were identified as being differentially expressed with 17 genes having ≥2 fold change. Real-time RT-PCR showed up regulation of <I>acylglycerol-3-phosphate O-acyltransferase 2</I> and <I>diacylglycerol O-acyltransferase 2</I> in CLA fed mice, both necessary for triglyceride biosynthesis. Expression of <I>B-cell leukemia/lymphoma 6</I>, a nuclear transcriptional repressor, and <I>signal transducer and activator of transcription 5B</I>, a transcription factor, were shown to be greater in the liver of CLA fed mice. Both genes are associated with immunoregulation. Comparing real-time RT-PCR to microarray data suggest a Bonferroni correction to microarray data is necessary in order to eliminate false positive data. Further verification of microarray results is needed to validate microarray data after a Bonferroni correction.

The purpose of this research was to evaluate line and sex differences in swine feeding behavior traits. Barrows and gilts used in the study were from three sire lines and two dam lines. Data were provided by PIC in Franklin, KY. Feeding behavior traits considered were average daily feed intake (ADFI), average occupation time/day (AOTD), average feed intake/visit (AFIV), average number of visits/day (ANVD), average feeding rate/visit (AFRV), average occupation time/visit (AOTV), and residual average daily feed intake (RADFI). Electronic feeders were used to measure feeding behavior traits on two pens per feeder. Use of the feeder alternated between the two pens weekly. Feeding behavior traits differed by line and sex. Production traits that were used in the study included: average daily gain (ADG), feed conversion ratio (FCR), backfat (BF), loin depth (LD), percent lean (% LEAN), and average daily feed intake (ADFI). For this study, ADFI was treated as both a feeding behavior and performance trait. Feeding behavior traits were used to calculate principal components. Principal components were then treated as traits in terms of statistical analysis.

Infant formula companies began fortifying formulas with long-chain polyunsaturated fatty acids (PUFA) in 2002, including arachidonic acid (AA) at ~ 0.5% of total fatty acids. This study is the first in a series that will examine effects of supra-physiological supplementation of AA on intestinal health. The objective was to determine the time specific effects of dietary AA on fatty acid composition of enterocyte phospholipids and on the mRNA abundance of hepatic ∆6- and ∆5-desaturases. One d old pigs (N=96) were fed a milk-based formula for 4, 8, or 16 d. Diets contained either no PUFA (0%AA, negative control), 0.5%AA, 2.5%AA, 5%AA, or 5% eicosapentaenoic acid (EPA) of total fatty acids. Growth (299 +/- 21 g/d) was unaffected by treatment (P>0.1). By day 16, ileal enterocyte phospholipid concentrations of AA were enriched 176%, 280%, and 355% in pigs fed the 0.5%AA, 2.5%AA, and 5%AA diets, respectively, compared with the 0%AA control (P<0.05). Concentration of AA within enterocytes of the 5% EPA fed group was similar to that of the 0%AA fed pigs, while EPA concentration increased by >8 fold. As pigs aged from birth to 16 d of age, there were no differences in the desaturase mRNA abundance (P>0.1), measured in pigs fed 0.5% or 5%AA. Abundance also was similar among AA-supplemented pigs, but was elevated by 60-80% in the 0%AA-fed pigs compared to those fed 2.5% (P<0.05). These data demonstrate a dose-dependent response in enterocyte AA concentration to dietary AA and show that supra-physiologic supplementation of AA is not detrimental to growth or desaturase gene expression.