Michael L. Thonney

Toxicologic studies in growing sheep fed silage corn cultured on municipal sludge‐amended acid subsoil

Field corn was grown on subsoil, pH 5.5, that had been amended with 100 dry tons per acre (224 metric tons per hectare) of municipal sewage sludge from Syracuse, New York. The corn plants containing 3.88 ppm dry weight of cadmium were field-chopped and ensiled, and the silage was fed to growing sheep for 225 d. The sheep fed the sludge-grown corn silage showed a significantly (10 higher feed efficiency, (2) higher hepatic microsomal p-nitroanisole O-demethylase activity, and (3) higher concentrations of cadmium in liver and kidney and nickel in kidney as compared to the control animals. No significant treatment effects were observed in mutagenic responses for animal feed or feces samples. No consistent treatment effects were noted during histopathologic examination of sheep tissues.

Effect of prolactin, β-lactoglobulin, and κ-casein genotype on milk yield in East Friesian sheep

The effect of prolactin (PRL), beta-lactoglobulin (beta-LG), and kappa-casein (CSN3) on milk yield was estimated in an East Friesian dairy sheep population from Old Chatham Sheepherding Company, New York. Genotypes were determined by PCR amplification followed by digestion with HaeIII and RsaI for PRL and beta-LG, respectively, and by PCR amplification for CSN3. Monthly milking records and pedigree information were used to evaluate the effect of each polymorphism on milk yield. Results indicated that PRL genotype had a significant effect on milk yield. Ewes carrying one A allele produced 110.6g more milk per day than ewes with no A alleles. There was no statistical difference between ewes with only one A allele and ewes with 2 A alleles. No association among polymorphisms at the beta-LG and CSN3 loci and milk yield was found. The results presented in this study indicate that the PRL gene is a potential marker that could be used in selection programs for improving milk yield in dairy sheep.

Genetically size-scaled growth and composition of Dorset and Suffolk rams

Thirty-four Dorset and 34 Suffolk rams were slaughtered in pairs within breed at birth, weaning, at monthly intervals to 420 days and then at bimonthly intervals until 600 days to compare factors used to estimate mature size and to determine how genetic size-scaling affects the comparison of body composition between breeds. At equal empty body weights there were no detectable differences between the breeds in amounts of water, protein or ash but Dorsets contained more lipid. Dorset and Suffolk asymptotic values of water (40 and 61 kg), water-plus-protein-plus-ash (51 and 77 kg), metacarpal bone length (127 and 147 mm) and metacarpal bone weight (59 and 101 g) were used to estimate mature size. Regardless of the estimator of mature size, there were no significant differences between breeds in degree of maturity at a given metabolic age. At the same degree of maturity within the estimators of mature size, there were no differences between breeds in the degree of maturity of water, protein or ash, with the exception of small differences in protein for two of the mature size indicators. Because lipid appeared to accumulate without limit in these sheep, the mature body was assumed to contain 300 g lipid per kg. Using this proportion to estimate amount of mature lipid, there was a higher degree of maturity of lipid for Suffolk than for Dorset rams at equal degrees of maturity of water, water-plus-protein-plus-ash or metacarpal bone weight. Thus, Dorsets with greater lipid content at equivalent empty body weights were leaner than Suffolks when adjusted for mature size.

Polyethylene glycol and polyvinylpirrolidone effect on bacterial rRNA extraction and hybridization from cells exposed to tannins

Abstract – In order to detect fluctuations in ruminal microbial populations due to forage tannins using16S ribosomal RNA (rRNA) probes, recovery of intact rRNA is required. The objective of this workwas to evaluate the effect of polyethylene glycol (PEG) and polyvinylpirrolidone (PVP) on extractionof bacterial rRNA, in the presence of tannins from tropical legume forages and other sources, thathybridize with oligonucleotide probes. Ruminococcus albus 8 cells were exposed to 8 g/L tannic acid or1 g/L condensed tannins extracted from Acacia angustissima , banana ( Musa sp.) skin, Desmodiumovalifolium , red grape ( Vitis vinifera ) skin and Inga edulis , or no tannins. Cells were rinsed with Trisbuffer pH 7 containing either 8% PEG or 6% PVP prior to cell lysis. Total RNA samples rinsed witheither PEG or PVP migrated through denaturing agarose gels. The 16S rRNA bands successfullyhybridized with a R. albus species-specific oligonucleotide probe, regardless of tannin source. Theeffect of rinsing buffers on the density of 16S rRNA bands, as well as on the hybridization signals wascompared. There were significant effects (P<0.01) when the controls were compared to either buffertreatments due to tannin type, buffer used and the interaction of tannin type and buffer. The significantinteraction indicates the influence of tannin type on the parameters evaluated.Index terms:

Toxicologic studies with pregnant goats fed grass-legume silage grown on municipal sludge-amended subsoil

Pregnant goats were fed grass-legume silage grown on soil amended with 112 dry metric tons per hectare of municipal sewage sludge from Syracuse, New York for 135 days. Whereas PCBs were not detectable in control or sludge-grown silage, cadmium was much higher (3.81 ppm) in the sludge-grown silage as compared to the control silage (0.14 ppm). There were no consistent differences in residues of cadmium in the goats milk or body tissues of the kids when compared to controls. The concentration of cadmium in the livers of the adult animals was significantly higher (p < 0.05) in the sludge treatment than controls. No significant treatment effects were observed in mutagenic responses for the goats milk. Interestingly, the pregnant goats fed the sludge-grown silage produced far too little milk for their kids while the control animals produced sufficient milk. There were no observable changes in the tissue ultrastructure as examined by electron microscopy for both the adults and the kids from either ration treatment.