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Biomedical subjects

M S Wolynetz

Publications and source records attributed to M S Wolynetz.

At least 37 records · Page 2Linked to original sources
PubMed1989

Effect of acclimatization to an excreta-collection harness on excreta energy voided during a nitrogen-corrected true metabolizable energy bioassay.

Two TMEn bioassays were made with adult cockerels to test the hypothesis that excretion inhibition, observed previously as induced by excreta-collection harnesses, can be overcome by a suitable acclimatization period. Each experiment was designed as a 2 x 2 x 3 factorial with normal birds and acclimatization birds fitted with harnesses or housed over collection trays and given one of three dietary treatments. The acclimatization period was 5.75 days. The harnesses generally reduced excreta energy output, and their removal was followed by a compensatory increase. Acclimatization failed to eliminate the harness effect.

Adaptation, Physiological↗
PubMed1988

Factors affecting length of herdlife in purebred and crossbred dairy cattle.

The proportional hazards model with censoring was used to assess the effects of breeding value, disease, calving, size, and udder and lactation traits on length of herdlife of 3881 heifers in five herds. Data were recorded over 10 yr from three lines: a Holstein line, an Ayrshire-based line, and a crossbred line. Influences on survival were assessed from data collected at birth, 34, 50, and 82 wk, first freshening, and at 112 and 308 d postpartum. Median estimated herdlife (age at 50% culling) was 3.9 yr for animals alive at first freshening and increased to 4.3 yr for those that completed a first lactation (308 d postpartum). Herds differed greatly in the pattern of culling after freshening. Crossbred females had 21 wk longer median estimated herdlife than the mean of the purelines at 308 d postpartum. Individual milk yield was positively associated with longevity and had the greatest impact on length of herdlife. Abortion and fertility measured as days to last insemination were negatively associated with length of herdlife. Large heifers tended to have increased longevity. High feed intake postpartum was associated with reduced length of herdlife. Objective measures of conformation, which included measurements of the udder, were not important in determining herdlife.

Animals↗
PubMed1988

Comparisons of bioassays for true metabolizable energy adjusted to zero nitrogen balance.

Four experiments were made with adult, Single Comb White Leghorn cockerels to investigate aspects of the bioassay for true metabolizable energy adjusted to zero nitrogen balance (TMEn). Collection of excreta in plastic bags held in place by harnesses (H) doubled the potential bird capacity of a standard cage arrangement relative to that wherein excreta are collected on trays (T). Housing H-birds in adjacent cages had no effect on fecal (F) and urinary (U) energy adjusted to zero nitrogen balance (FEn + UEn) irrespective of whether neighboring birds were fed or fasted. Extension of the preassay fast to 48 h did not prevent the reduction in FEn + UEn, seen in previous experiments, of H-birds relative to that of T-birds. Extension of the preassay fast to 48 h, provision of supplemental glucose, and the variation of test material inputs from 30 to 50 g did not substantially effect TMEn estimates or their precision: supplemental glucose reduced body weight loss, but the appearance of glucose in an excreta sample was a cause for concern. Provision of supplemental water by intubation during fasting and excreta-collection periods had little effect on the variance of FEn + UEn values of fed or fasted birds, and no effect on TMEn estimates. Although excreta collection with H has several advantages, there can be a high incidence of sample loss due to H slippage: 21, 2, 0, and 22% in Experiments 1, 2, 3, and 4, respectively. The reduced FEn + UEn of H-birds is a problem requiring explanation. In terms of data quality, none of the assay modifications was beneficial.

Animals↗
PubMed1987

Effects of dietary fat level and lysine:energy ratio on energy utilization and tissue synthesis by broiler chicks.

An experiment was designed to estimate the effect of dietary fat (20 or 80 g/kg) on the responses of broiler chicks to changes in the ratios of bioavailable lysine (LB) to true metabolizable energy corrected to zero nitrogen balance (TMEn) in their diets. A comparative slaughter experiment used an initial slaughter group of 44 10-day-old male chicks; an additional 120 chicks from the same population were used in the 14-day experiment. Dietary treatments comprised two basal diets differing in fat content and formulated to have similar nutrient:TMEn ratios. Each basal diet was supplemented with four levels of lysine to provide four LB:TMEn ratios calculated, and subsequently found, to be the same in each basal diet series. Each of the eight diets was diluted with five levels of cellulose to ensure a range of intakes under ad libitum feeding. Three individually housed chicks were assigned to each of the 40 diets. Carcasses were assayed for water, nitrogen, lipids, ash, and gross energy; changes in these variables during the experiment were the response criteria. The fat content of the diet had no effect (P greater than .05) on the chick responses to LB:TMEn ratios. At a fixed energy intake the body weight gain, retained water, retained energy as protein and retained ash increased with the LB:TMEn ratio, with no conclusive evidence of a maximum response having been reached for any variable at an LB:TMEn ratio of .83 g/MJ. Retained energy was independent (P greater than .05) of the LB:TMEn ratio but the energy retained as neutral lipids tended to decrease as the ratio increased. The data support the view that the lysine requirement of the broiler chick varies according to the response criterion used in its assessment.

Animals↗
PubMed1987

Need for comparative slaughter experiments in poultry research.

The comparative slaughter technique is a protocol used to estimate changes in the body composition of birds during an experiment. The protocol is based on the assumption that the body composition of the experimental group of birds (EG) at the beginning of an experiment can be predicted accurately and precisely from the carcass compositions of comparable birds from the same population that are slaughtered at the beginning of the experimental period. The present study examines the need for the initial slaughter group (ISG) of birds. By reexamining data from three previously published experiments that used broiler chicks and one that used adult cockerels, it is demonstrated that the same inferences can be obtained by an appropriate analysis of covariance using only the data from the EG birds. Elimination of the ISG results in a considerable reduction in the resources required for experimentation and means that the inferences are based on data obtained only from birds subjected to the various treatments.

Animal Nutritional Physiological Phenomena↗
PubMed1987

A comparison of the amounts of energy and nitrogen voided as excreta by cockerels housed over trays or fitted with harnesses and plastic collection bags.

Three experiments using adult Single Comb White Leghorn cockerels were made to compare the amounts of energy and nitrogen voided as excreta when collected either in plastic bags held in place by harnesses (H) or on trays placed below the wire-floored cages (T). In the first experiment, previously fasted birds were given, by intubation into the crop, 30 g of ground yellow corn or meat meal; other birds continued to be fasted. Excreta were collected for 48 h. The second experiment was similar but included five feedingstuffs and a second excreta collection was made on trays during the 48 to 72-h period postfeeding. The third experiment also involved 0 to 48 and 48 to 72-h collections but the input was a laying hen diet in amounts ranging from 0 to 50 g by 10 g increments. Birds fitted with harnesses voided less excreta energy than T-birds but the output of excreta nitrogen was independent of the collection method. The differences between H and T-birds were independent of the nature and amount of feed input. Removal of harnesses resulted in compensatory excreta energy output in the subsequent 24 h. The H minus T differences were not attributable to outliers within a group because variances were generally similar among collection methods. The reduced excreta energy outputs of H-birds tended to cause higher estimates of true metabolizable energy for the feedingstuffs but the effect was modified because both fasted and fed birds were affected by the harnesses.

Animal Feed↗
PubMed1986

Influence of Location, Host Cultivar, and Inoculation on the Composition of Naturalized Populations of Rhizobium meliloti in Medicago sativa Nodules.

A phage typing system was used to evaluate the composition of indigenous populations of Rhizobium meliloti inhabiting nodules of Medicago sativa cultivars grown with and without inoculation at two field sites during 1983 and 1984. Soil at both locations contained established populations of R. meliloti at planting. Analysis of 1,920 nodule isolates revealed 55 unique phage types of indigenous R. meliloti at one site and 65 indigenous types at the other location. The distributions of phage types differed markedly between locations. At one site, the nodule population was dominated by two phage types; seven others occurred consistently but at lower frequency, and the remainder were encountered infrequently. No indigenous types predominated at the other location, although nine occurred more frequently than the remaining types. Indigenous R. meliloti predominated in nodules from inoculated plots at both sites, with inoculant recovery varying between 10 and 38% in each of two years. The frequency of occurrence of particular phage types at one location was significantly influenced by both M. sativa cultivar and inoculation. At this location, the interaction of cultivar and inoculation on the incidence of phage types suggests that the presence of an inoculant strain differentially affected nodule occupancy of M. sativa cultivars by members of the indigenous R. meliloti population. At both sites, the frequency of specific phage types differed between years. The data emphasize the importance of understanding the ecology and characteristics of indigenous Rhizobium populations as a prerequisite for elucidating problems of inoculant establishment and persistence in competitive situations.

Journal Article↗
PubMed1986

Comparison of three methods of excreta collection used in estimation of energy and nitrogen excretion.

Three methods of excreta collection: plastic trays (T), human colostomy bags affixed to the bird (B), and B containing 25 ml .5 N HCl (A) were compared in three experiments with adult, Single Comb White Leghorn cockerels. There were 128, 130, and 120 birds in Experiments 1, 2, and 3, respectively, from which 97, 84, and 105 excreta samples were obtained; most of the losses occurred among the B- and A-groups. Birds were fasted for 24 hr prior to the experiments and then precision-fed, by intubation, with 0, 5, 10, 15, 20, 25, 30, or 35 g of fish meal (Exp. 1) or soybean meal (Exp. 2). In the third experiment, the inputs were 30 g of corn, fish meal, soybean meal, and a 50:50 (wt/wt) blend of fish meal and soybean meal; control birds were fasted. Excreta were collected for 48 hr after feeding, and the outputs of excreta energy (FE + UE), excreta nitrogen (FN + UN), and (FE + UE) corrected to zero nitrogen balance (FEn + UEn) were measured. True metabolizable energy (TME) values and TME corrected to zero nitrogen balance (TMEn) were calculated. In Experiments 1 and 2, the regressions of (FE + UE), (FN + UN), and (FEn + UEn) on feed input had slopes which were independent of excreta collection methods (P greater than .05), indicating that estimates of TME and TMEn based upon the linear regression assay were not different (P greater than .05). In both experiments, the levels of excreta and energy output using T were greater (P less than .01) than when using B.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1986

Measurement of lipids in chicken carcass dry matter.

Three procedures were used to measure the lipid fraction of chicken carcass dry matter. The resulting data were evaluated by calculating carcass residuals (carcass dry matter-protein-ash-lipid) and by application of multiple linear regression to estimate the energy values of carcass fat and protein. Petroleum ether extraction led to carcass residuals of about 5% and an estimated energy value of protein that was larger than previous estimates. Chloroform:methanol (2:1) extraction gave a negative residual (-6.5%) and a very low predicted energy value for protein. However, when the chloroform:methanol extract was corrected for crude protein content, the residual was approximately 1.0% of the dry matter, and the energy estimates were similar to those obtained previously. The importance of conducting analytical analyses in duplicate is illustrated.

Animals↗
PubMed1985

Reproductive performance of Finnish Landrace and Suffolk sheep maintained indoors year-round.

The reproductive performance (fertility and prolificacy) of Finnish Landrace (Finn) and Suffolk sheep on an accelerated breeding program was evaluated. Both breeds were contained in each of two separate flocks housed indoors year-round on expanded metal floors in windowless buildings. The two flocks were bred alternately at 4-mo intervals in January, May and September. The sheep were exposed to either an abrupt (ALR) or constant (CLR) lighting regimen. Data from nine breedings during a 4-yr period were considered. Fertility was significantly higher for ewes in the ALR lighting regimen. Fertility was lower for ewes bred in September. For ewes that had lambed from breeding 8 mo earlier, fertility was higher for Finn ewes than for Suffolk ewes; however, similar fertility levels were observed in both breeds if the ewes had not lambed following the previous breeding. Higher prolificacy was observed in the Finn ewes than in the Suffolk ewes, but the differences in prolificacy varied with the month of breeding. The probability of a ewe having more than one lamb was significantly higher for Finn ewes than for Suffolk ewes in both January and May breedings, but was similar in September breedings. Incorporating the Finnish Landrace breed into an accelerated breeding program for sheep maintained indoors year-round is a practical way to increase the number of lambs born. Controlling daylength and dividing the flock into smaller flocks are also practical procedures to increase lamb production.

Animals↗
PubMed1985

The bioavailability of supplementary lysine and its effect on the energy and nitrogen excretion of adult cockerels fed diets diluted with cellulose.

A basal diet formulated to be deficient in lysine was supplemented with five levels of L-lysine monohydrochloride and each of the resulting diets was diluted with six levels of cellulose. Each of the 30 diets was precision fed (30 g/bird) to adult cockerels which had been fasted for 24 hr, and excreta voided during the 48 hr following feeding were collected. Twelve fasted birds served as controls. Feed and excreta samples were assayed for lysine, energy, and nitrogen. The bioavailability of the natural lysine was 88.2 +/- 2.5% whereas that of the L-lysine HCl was approximately 92%, significantly (P less than .05) less than the 100% often assumed in lysine requirement studies. The supplemental lysine did not significantly affect (P greater than .05) estimates of bioavailable energy [true metabolizable energy (TME), TME corrected to zero nitrogen balance (TMEn)]. Cellulose dilution had no significant (P greater than .05) effect on either lysine or energy availability.

Animals↗
PubMed1985

The excreta energy and nitrogen losses of adult cockerels during a fast.

Sixteen adult Single Comb White Leghorn (SCWL) cockerels were fasted for 48 hr and then placed on an experiment during which they were fasted for an additional 11 days; water was freely available. Excreta energy (FE + UE), excreta nitrogen (FN + UN), and excreta energy corrected to zero nitrogen balance (FEn + UEn) losses were measured at 24-hr intervals as were body weights (BW) and weight losses (delta BW). One bird died on the second day of the experiment. There were significant differences (P less than .01) in excreta losses among birds and days. The day effect was curvilinear and decreasing, with the largest day-to-day changes tending to occur early in the experiment. The BW, delta BW, and ambient temperature had little effect on the losses with the exception of (FN + UN) which varied in part with BW. The regression of FE + UE on FN + UN, after adjusting for birds and days, yielded a slope estimate of 33.54 +/- 5.12 kJ/g (8.02 +/- 1.22 kcal/g) of nitrogen which is not different (P greater than .05) from values commonly used to corrected bio-available energy values to zero nitrogen balance.

Animals↗
PubMed1985

Changes in the body weights and the final carcass compositions of adult cockerels fed less than their maintenance requirements.

Seventy-two adult Single Comb White Leghorn (SCWL) cockerels of each of two strains were fasted for 48 hr. Twenty-four birds of each strain were killed and frozen. Eight birds of each strain were fasted for an additional 11 days and 4 birds of each strain received, by intubation, 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50 g of a high energy feed daily for 10 days, after which they were fasted for 48 hr. Birds were weighed and their excreta were collected at 24-hr intervals. At the conclusion of the experiment, all birds were killed and their carcasses, together with those of the initial slaughter group (IS), were assayed for water, protein, fat, and ash. All experimental birds lost weight. The change in body weight (delta BW) decreased linearly as feed input increased. Solution of the derived regression equation provided a mean estimate of .355 MJ/BW.75 kg/day (.0848 Mcal/BW.75 kg) for the energy requirement to maintain body weight. The estimate fails to take account of changes in body composition, but correction for this was impractical because of the large among bird variation. For the fasted birds, the delta BW displayed a logarithmic-decay pattern over time. Carcass protein and water increased with feed input but carcass fat was independent of feed input. However, the proportions of the carcass constituents did not vary with feed input. The proportion of carcass protein was greater and of carcass fat less at the end of the experiment than in the IS birds.

Animals↗
PubMed1984

Fertility of ewe lambs maintained indoors year-round on an accelerated breeding program.

Data from records of 330 crossbred ewe lambs mated to 142 rams over 11 breeding periods were analyzed for lambing percentage to one service. These ewe lambs in two separate flocks were reared and maintained indoors year-round and were derived from the three synthetic crossbred strains being developed at the Animal Research Centre in Ottawa, Ontario, Canada. At first exposure to rams, the ewes were 6 to 7 mo of age and had no hormonal treatments to induce or synchronize estrus. The two flocks were bred alternately in January, May or September to establish an 8 mo breeding cycle. The rams were at least 10 mo old and were maintained in one of two lighting regimens. Fifteen percent of the ewes lambed and the average prolificacy was 1.6. It appears that ewe lambs mated to rams maintained in a constant day length (10 h light: 14 h dark/24 h) environment had lower fertility than those ewe lambs mated to rams maintained in an environment such that the day length was altered between 4 mo of 10 h light: 14 h dark/24 h and 4 mo of 18 h light: 6 h dark/24 h. Although the fertility level was low, the data suggest that the breeding of ewes 6 to 7 mo of age is feasible.

Animal Husbandry↗
PubMed1984

A longitudinal study of energy and nitrogen excretion by fasted cockerels.

An experiment was conducted in which the energy and nitrogen voided by cockerels during the final 48 hr of each of 14 72-hr fasts, 28 days apart, were measured. There were 12 Single Comb White Leghorn cockerels of each of two strains aged 150 days at the time of the first excreta collection and 12 birds from each of two meat-type strains aged 268 days at the first collection. Birds that died during the experiment were replaced by similar birds maintained under comparable conditions. Both excreta energy (FE + UE) and excreta nitrogen (FN + UN) varied among time periods and among birds and appeared to be related to metabolic body size. Similar patterns were observed when the FE + UE data were corrected to zero nitrogen balance (FEn + UEn ). There was a significant (P less than .01) quadratic relationship between ambient temperature and FE + UE, FN + UN, and FEn + UEn with higher excreta outputs being associated with either low or high temperatures. Frequently, but not inevitably, higher FE + UE and FN + UN were observed prior to death. The FE + UE was significantly (P less than .01) correlated with FN + UN. In general, the estimated regression coefficient relating energy to nitrogen output was similar to the value, based upon the energy content of chicken urine, used to correct FE + UE to FEn + UEn . However, the analyses indicated that the correction factor may vary among birds or over time and may be related to metabolic body weight. To what extent this variability can be defined and incorporated into metabolic energy assays requires further investigation.

Animals↗
PubMed1982

Effect of PMSG on the reproductive performance of totally confined ewes bred at synchronized estrus.

The reproductive performance (fertility, prolificacy and fecundity of totally confined sheep in a controlled breeding program at the Animal Research Centre (ARC) was analyzed to evaluate the effect of pregnant mares' serum gonadotrophin (PMSG) on ewes synchronized for estrus with fluorogestone acetate (FGA). PMSG did not significantly enhance reproductive performance. Fertility for ewes receiving 500 IU PMSG was 57% and for ewes not receiving PMSG it was 47%. Corresponding values for prolificacy were 2.4 and 2.2, and for fecundity, 144 and 103%. The reproductive performance was not affected by any of the other factors (flock, strain, lighting regime, ram age or reproductive status of the ewe) indigenous to the controlled breeding program for sheep housed in total confinement.

Journal Article↗