bluuebunny/crossref_metadata_2025 huggingface dataset:
EFFECT OF ABRUPTLY ADDING BUFFERS TO THE RATIONS OF LACTATING DAIRY COWS
Authors: BLOCK ELLIOT , MULLER L. D.
Published: March 2010

Feeding 0.23 kg of sodium bicarbonate plus 0.07 kg of magnesium oxide per day to cows with a milk fat depression tended to reduce dry matter intake temporarily. Milk production declined by 1.2 kg/day, milk fat increased by 0.43%, and rumen fluid pH increased as a result of buffer additions. There was also a trend toward higher blood alkaline indices. Key words: Buffers, lactating cows, sodium bicarbonate, magnesium oxide, milk fat depression
EMBRYO MANIPULATION AND GENE TRANSFER IN LIVESTOCK
Authors: CHURCH R. B. , SCHAUFELE F. J. , MECKLING K.
Published: March 2010

In the past few years significant progress has been made in manipulation of reproduction and in development of genetic engineering techniques which can be applied to animal species. Artificial insemination and embryo transfer are now used widely in the livestock industry. The advent of non-surgical embryo collection and transfer, embryo freezing and splitting along with estrus synchronization has allowed the industry to move from the laboratory to the farm. Embryo manipulation now involves embryo splitting to produce monozygotic twins, in vitro fertilization, cross-species fertilization, embryo sexing, and chimeric production of tetraparental animals among others. Advances in recombinant DNA, plasmid construction and embryo manipulation technologies allow the production of genetically engineered animals. The application of recombinant DNA technology involves the isolation and manipulation of desired genes which have potential for significant changes in productivity in genetically engineered livestock. Recombinant DNA constructs involve the coupling of promoter, enhancer, regulatory and structural DNA sequences to form a "fusion gene" which can then be multiplied, purified, assayed and expressed in cell culture prior to being introduced into an animal genome. Such DNA gene constructs are readily available for many human and mouse genes. However, they are not readily available for livestock species because the detailed molecular biology has not yet been established in these species. Gene transfer offers a powerful new tool in animal research. Transfer of genes into the bovine genome has been accomplished. However, successful directed expression of these incorporated genes has not been achieved to date. New combinations of fusion genes may be an effective way of producing transgenic domestic animals which show controlled expression of the desired genes. Embryo manipulation and genetic engineering in livestock species is moving rapidly. The problems being addressed at present in numerous laboratories will result in enhanced livestock production in the not too distant future. Key words: Embryo transfer, embryo manipulation, transgenic livestock, genetic engineering, gene transfer, monozygotic twins
THE ROLE OF GENE TRANSFER IN ANIMAL AGRICULTURE AND BIOTECHNOLOGY
Authors: WAGNER THOMAS E.
Published: March 2010

Biotechnology in general, and mammalian recombinant genetics in particular, assuredly will have a major impact on all aspects of animal science and commercial livestock production. A review of the basic molecular biology and technology involved in gene transfer in mammalian species is presented in the content of potential commercial application of these new procedures for enhancing productivity in livestock. Special emphasis is given to near-term possibilities for the application of mammalian recombinant genetics to animal growth and lactation. Key words: Biotechnology, gene transfer, livestock production
GENETIC ENGINEERING TO IMPROVE RESISTANCE TO VIRAL DISEASES OF POULTRY: A MODEL FOR APPLICATION TO LIVESTOCK IMPROVEMENT
Authors: CRITTENDEN L. B. , SALTER D. W.
Published: March 2010

Several genetic engineering approaches can and will be used to control viral diseases in chickens. One approach is to insert genes for resistance in the germ line of the chicken. The endogenous avian leukosis virus (ALV) genes that segregate in the chicken serve as a natural model for germ line insertion and expression. One gene controls the expression of endogenous ALV envelope antigen. Chickens carrying that gene are resistant to infection with endogenous ALV. We propose, as a model, to insert the envelope gene of exogenous ALV, thus inserting a dominant gene for resistance to exogenous ALV. Our approach to germ line insertion in the chicken, including insertion methods, vectors and testing, is discussed. Genetic engineering approaches to animal breeding will only be useful as methods to enhance the efficacy of present breeding methods. Gene insertion can add new genetic variation by crossing the species barrier, and by introducing genes into highly productive lines one at a time. Molecular methods may also be useful for the introduction of chromosomal markers and to help identify major genes influencing phenotypes controlling productive efficiency. Key words: Germ line, vectors, retrovirus, chicken, endogenous virus, lymphoid leukosis
APPLICATION OF GENE MANIPULATION TO RUMEN MICROFLORA
Authors: TEATHER RON M.
Published: March 2010

The potential impact of genetic manipulation of microorganisms has been fundamentally altered by the development of gene cloning and DNA synthesis techniques. Classical microbial biochemistry and genetics provided a rationale and methodology for the development of industrial fermentations in which an existing metabolic pathway of an organism could be exploited, directing a major part of the organism's synthetic capacity toward the production of a desired end product. Strains developed for these purposes, however, are able to survive only under controlled conditions in which competition from normal strains does not exist. Gene cloning and DNA synthesis techniques extended the range of products possible in such industrial fermentations to include essentially any material of biological origin. More fundamentally, however, these techniques have created an opportunity to introduce new genetic information into natural ecosystems, where a novel gene product or metabolic pathway may have a profound effect even when the level of gene expression is kept low enough to have minimal effect on the competitive fitness of the producing organism. A potential target for the introduction of such new genetic information is the rumen ecosystem. Goals might include the modification of fermentation products, the introduction of improved or novel pathways for the degradation of feedstuff s, the suppression of undesirable metabolic pathways, and the production of novel substances which can directly affect the animal's physiology. At the present time a number of technical barriers to the application of gene cloning techniques to rumen microorganisms remain to be overcome. In addition, questions of both utility and safety must be resolved. These goals and barriers are discussed, together with a presentation of work in progress on gene cloning in rumen bacteria which includes the transfer of genetic information from Escherichia coli to rumen bacteria, and from rumen bacteria to E. coli, and the development of synthetic genes for expression in rumen bacteria. Key words: Gene manipulation, rumen, bacteria, Escherichia coli
CALVING AND PREWEANING PERFORMANCE OF CROSSBRED PROGENY OF SOME FOREIGN AND DOMESTIC BEEF CATTLE BREEDS
Authors: NEWMAN J. A. , TONG A. K. W. , FREDEEN H. T. , RAHNEFELD G. W.
Published: March 2010

Charolais-, Simmental- and Limousin-sired calves are compared for calving traits and preweaning growth based on observations of 3939 calves born in 48 western Canadian beef cow herds of Hereford, Angus and Shorthorn breeding during the period 1970–1972. Hereford cows produced calves with longer gestation lengths, higher birth weights, slower preweaning growth, and lower weaning weights than Angus cows. Shorthorn cows produced progeny with the shortest gestation lengths and intermediate performance in other traits. Limousin sires produced calves with the longest gestation lengths, the least calving difficulty, the lightest birth weights, the lowest birth-to-weaning mortality, and the slowest preweaning growth. Charolais-sired and Simmental-sired calves did not differ significantly in gestation length, postnatal mortality or preweaning growth rate, but Simmental-sired calves were lighter at birth and calved more easily. Breed-of-sire effects interacted with breed-of-dam effects for birth weight and with sex-of-calf effects for calving ease and most measurement traits, but these interactions did not generally involve a re-ranking of sire breeds. The economic impact of the results is briefly discussed. Key words: Beef cattle, breed effects, preweaning traits
SEPARATION OF THE EFFECTS OF AGE, BODY WEIGHT AND GAIN ON PREGNANCY RATES OF BEEF HEIFERS BY PRINCIPAL COMPONENT ANALYSIS
Authors: MAKARECHIAN M. , FARID A. , BERG R. T.
Published: March 2010

Pregnancy records of 174, 2-yr-old heifers from four beef breed groups — Hereford (HE), Beef Synthetic (SY), Crossbred Hereford (HX) and Dairy Synthetic (SD) — were used in a principal component analysis. Four principal components (PC) were required to explain at least 90% of the total variation which existed in the dependency structure of birth date, birth weight, preweaning daily gain, weaning weight, weaning to yearling daily gain, yearling weight, yearling to breeding daily gain and weight at the start of breeding season in each of the breed groups. The interpretation of each of the four PCs was fairly consistent in the four breed groups. Principal component analysis separated variation in the dependency structure of the above eight variables into preweaning daily gain and body weight (PC1), age (PC2), weaning to yearling daily gain (PC3) and yearling to breeding daily gain (PC4) indices. Birth weight was less emphasized by PC1 in the HE compared with the other breed groups. Birth date (age) was highly emphasized by PC2 in all the breed groups except the HE, in which there was moderate emphasis on both birth date and birth weight. Regression equations of pregnancy rate on the factor scores were different among the four breed groups. For the HE and SY heifers, preweaning and body weight index was the only component that was significantly related to pregnancy rate and it explained 30 and 23.7% of the variation, respectively. None of the components affected variation in pregnancy rate in the HX heifers. Pregnancy rate had a curvilinear relationship with the weaning to yearling gain index in the SD. The results of regressing pregnancy rate on factor scores derived from the principal component analysis indicated that generally when variation in age is small (as a result of short breeding season), weight gains and body weights of heifers have much greater influence on pregnancy rate than their age. Key words: Beef cattle, heifer reproduction, principal component analysis, age, body weight, gain
COMPARISON OF THE EFFECTS OF LOW-VOLTAGE ELECTRICAL STIMULATION ON MATURE AND YOUNG COW CARCASSES
Authors: HAWRYSH Z. J. , WOLFE F. H.
Published: March 2010

The quality characteristics of semitendinosus (ST) and longissimus dorsi (LD) roasts from 18 young and 6 mature cow carcasses subjected to low-voltage (110 V) electrical stimulation (ES) were determined. ES was applied for either 4 min or 5 min. Evaluations were conducted on meat obtained from young control sides (no ES) aged 48 h, from young and mature ES sides aged 48 h and from mature ES sides, aged 7 days. Data obtained from mature control sides (no ES), aged 48 h and 7 days, reported in a previous study, served as a reference point for mature ES meat. ES caused a reduction (P < 0.01) in pH values 1 and 4 h postmortem. At 24 h, the pH of ST and LD muscles from control and ES carcasses were similar. Cooking losses of roasts were not affected by ES, ES duration or increased aging. Trained panelists detected no significant effects of ES, ES duration or aging time on palatability. Consumer panel judgements of ST roasts were similar to those of the trained judges. Data from instrumental measurements of juiciness (water-holding capacity), tenderness (OTMS) and softness (penetrometer) for ST and LD roasts support sensory results. These studies show no differences in cooking and eating quality of ST and LD roasts attributable to low voltage ES. The palatability of meat from mature ES carcasses was judged to be similar to that of comparable meat from young control carcasses. For meat from young carcasses, there was no advantage in increasing ES duration. In addition, roasts from mature ES carcasses aged for either 48 h or 7 days were similar. Key words: Low voltage electrical stimulation, cow carcasses
INFLUENCE OF DIETARY MANGANESE ON TISSUE TRACE MINERAL ACCUMULATION AND DEPLETION IN SHEEP
Authors: BLACK J. R. , AMMERMAN C. B. , HENRY P. R. , LITTELL R. C.
Published: March 2010

An experiment was conducted to investigate tissue trace mineral accumulation and depletion in sheep fed high dietary Mn in the form of reagent grade MnO. During the pre-trial phase, 32 wethers, 56 kg initially, were group-fed the basal corn-soybean meal diet (36 mg/kg Mn) for 8 days at which time eight sheep were slaughtered and tissues were taken to represent controls. For the remaining sheep, the experiment was divided into two phases of 6 wk and 12 wk; during the first phase (accumulation), the diet contained 8000 mg/kg supplemental Mn and during the second phase (depletion) the diet was the unsupplemented basal. Sheep were slaughtered at various intervals during both phases and tissue samples were taken. Manganese increased in all tissues measured during accumulation but decreased rapidly during the depletion phase. In general, liver and kidney Zn and Cu increased during the accumulation phase but tissue Fe decreased during this phase. MnO appeared to be a relatively safe supplemental source of Mn for sheep. Key words: Manganese, trace minerals, tissue minerals, sheep
COMPARISON OF WILTED SILAGES OF ALFALFA CUT AT TWO STAGES OF MATURITY WITH FORMIC-ACID-TREATED SILAGE FROM EARLY-CUT ALFALFA
Authors: ATWAL A. S.
Published: March 2010

First cut alfalfa was harvested at early bloom and stored as early-cut formic-acid-treated silage (EFS) and early-cut wilted silage (EWS). Late-cut wilted alfalfa silage (LWS) was harvested 15 days later. Dry matter (DM) yields were 2.91, 2.82 and 3.12 tonnes/ha, respectively, for EFS, EWS and LWS. In the same order, for feeding in spring of the subsequent year, recoveries from storage were 79.8, 85.6 and 86.0% of DM; 84.1, 92.3 and 88.1 of energy; and 77.6, 91.5 and 92.2% of crude protein (CP). Ad libitum DM intakes were not significantly different (102.6, 99.7 and [Formula: see text] for the three treatments, respectively). Late-cut forages (both fresh and wilted) were significantly (P < 0.05) higher in fiber fractions (lignin and acid detergent insoluble nitrogen) than the early-cut forages. Similar trends persisted among the silages at feeding time after 9 mo of storage. Differences in the chemical composition and digestibilities of nutrients for EFS and EWS were small and statistically not significant (P > 0.05). When fed at maintenance level, the digestibility values for DM, energy and cellulose were significantly (P < 0.05) higher for EWS than for LWS but not for EFS. However, when fed ad libitum in combination with corn silage (1:1 DM basis), there were no significant effects of either harvesting date or wilting vs. formic acid treatments on the digestibility of nutrients. Key words: Alfalfa, silages, digestibility, formic acid, maturity stage, wilted silage
A COMPARISON OF MONENSIN AND CHLORTETRACYCLINE IN HIGH-CONCENTRATE AND HIGH-FORAGE DIETS FOR IMPLANTED AND NONIMPLANTED FINISHING STEERS AND HEIFERS
Authors: BEACOM S. E. , MIR Z.
Published: March 2010

In a factorial design experiment, 452 steers and heifers were fed ground forage or rolled grain-based diets supplemented with chlortetracycline (CTC) or monensin (MON). The effects of implanting steers with either 200 mg progosterone and 20 mg estradiol benzoate (PEB) or 36 mg resorcylic acid lactone (RAL) and heifers with 200 mg testosterone propionate and 20 mg estradiol benzoate (TEB) were also determined. On average, grain-fed cattle gained faster (P < 0.01) than forage-fed cattle, requiring 13 days less to reach finished condition. They also required 13% less feed per unit gain (P < 0.01) and dressed out 1.29 percentage units higher than forage-fed cattle but "cut out" only 0.4 percentage units higher, returning $18.78 more per head to labor. Heifers, averaging across all other treatments, gained slower (P < 0.05), required 6.7% more feed per unit gain but dressed out and "cut out" as well as steers, to return $7.39 less to labor per head. Cattle fed diets supplemented with MON took 4 days longer to finish, ate less (P < 0.05) feed but did not gain significantly more efficiently than those fed CTC-supplemented rations. Steers fed MON also had lower (P < 0.05) dressing percentages and returned $10.09 less per head to labor. Implanted cattle gained (P < 0.01) faster and more efficiently but required the same number of days to reach finished condition as did unimplanted cattle, thus producing heavier carcasses and returning to labor, on average, about $17.93 and $12.26 more for steers and heifers, respectively. The acetic/propionic acid ratio in the rumen fluid was significantly lower for cattle fed diets containing MON than for those fed diets fed CTC. Cattle fed forage-based diets and those receiving implants yielded significantly leaner carcasses than those fed grain-based diets or those receiving no implant. Key words: Monensin, chlortetracycline, implants, forage, beef steers, beef heifers
DIGESTIBILITY AND FEEDING VALUE OF FROST-DAMAGED CANOLA SEED (LOW GLUCOSINOLATE RAPESEED) FOR GROWING PIGS
Authors: BELL J. M. , KEITH M. O. , KOWALENKO W. S.
Published: March 2010

Digestibility trials with 57-kg pigs were conducted on blended canola seed (B. napus 'Regent') containing 20, 45 and 65% frost-damage fed in conjunction with a barley, wheat, soybean meal basal diet, supplemented with minerals and vitamins. The seed was fed whole, ground, pelleted and ammoniated. The seed contained, per kilogram, 18–20% crude protein, 22–35% ether extract, and 21.7–24.5 MJ gross energy. Glucosinolate concentrations were 15–33 μmole/g, oil-free basis. Grinding improved energy digestibility of the seed per se from an average of 34.4 to 62.8% and protein digestibility from 17.0 to 65.3%. Pelleting improved energy digestibility of whole seed from 31.6 to 65.5% and grinding before pelleting gave 69.2%. Pelleting, in addition to grinding, did not further improve protein digestibility over grinding alone. Ammoniation improved the digestibility of energy in ground seed from 61.2 to 66.9% and in ground pelleted seed from 69.2 to 72.4%. Ammoniation increased protein digestibility in ground seed from 61.6 to 65.2% and in pelleted seed from 62.1 to 63.1%, corrected for ammonia intake which was assumed to be of little value to the pig. Digestible energy values of processed seed were 15.6 to 17.7 MJ/kg and digestible crude protein values were 12.3 to 14.0% of dry matter. Frost-damaged canola seed was shown to be worth 20–50% more than good barley. Key words: Rapeseed, frost damage, digestibility, pigs, feeding value
SELECTED PHYSIOLOGICAL EFFECTS RESULTING FROM ADDITION OF SODIUM BICARBONATE TO DIETS FOR YEARLING HORSES
Authors: DEUEL N. R. , LAWRENCE L. M. , ALBERT W. W.
Published: March 2010

Sodium bicarbonate or a commercial vitamin-mineral mixture was included at the 1% level (air-dry weight) in the diets of 16 yearling horses over a 140-day period in a 2 × 2 factorial design. Feed additives resulted in a pH range from 5.78 to 7.87 in the concentrate portion of the diets. Feces, urine and venous blood were collected 24 h after feeding the concentrate. Average daily gain, respiration rate, venous pCO2 and pO2, as well as serum K, Cl, Ca, P, urea N and protein levels were unaffected by treatment. Horses receiving the vitamin-mineral supplement had higher serum Na and lower serum glucose concentrations than horses not receiving the supplement. Horses receiving sodium bicarbonate had a higher urine pH, lower fecal pH, higher packed cell volume, lower blood pH and lower serum glucose concentrations at 24 h after a meal than horses not receiving the buffer. Key words: Horse, sodium bicarbonate, dietary supplements, hematology
SCROTAL CIRCUMFERENCE, SEMEN CHARACTERISTICS, GROWTH PARAMETERS AND THEIR RELATIONSHIPS IN YOUNG BEEF BULLS
Authors: MAKARECHIAN M. , FARID A. , BERG R. T.
Published: March 2010

The records of sixty-six yearling and 2-yr-old beef bulls selected for breeding in 1980 and 1981 were used to study the relationships between body weight (BW) and gain measurements, scrotal circumference (SC) and semen characteristics in young beef bulls. The bulls belonged to four breed groups; Hereford, Beef Synthetic, Dairy Synthetic and Pee Wee. A week before the start of breeding season, the bulls were weighed and measured for scrotal circumference. A single prebreeding semen sample was collected by electro-ejaculator from each bull in 1980, while three samples (pre-, mid- and postbreeding) were collected by artificial vagina in 1981. The mean SC ranged from 31.3 cm in the Pee Wee to 38.6 cm in the Beef Synthetic, while SC per 100 kg BW was maximum in the Pee Wee (8.36%) and minimum in the Dairy Synthetic group (6.28%, P < 0.05). The relationship between BW and SC was linear within yearling and 2-yr-old bulls. Age did not have any effect on SC over and above BW within each age group. Preweaning daily gain accounted for a higher fraction of variation in SC compared to BW in all the breed groups except Dairy Synthetic. The relationships between BW, SC and feedlot daily gain with semen quality and quantity were positive but generally small (r < 0.30, P > 0.11). Semen volume and sperm motility had lower values and percent secondary abnormalities were higher in prebreeding compared with mid- or postbreeding samples. Repeatability estimates of the semen characteristics were generally low, ranging from 0 to 0.49. Key words: Beef bulls, scrotal circumference, semen characteristics, growth rate
EVALUATION OF BULL AND COW FERTILITY AT PASTURE IN SINGLE-SIRE MATING
Authors: MAKARECHIAN M. , FARID A. , BERG R. T.
Published: March 2010

Pregnancy rates and calving dates of beef cows in 27 single-sire breeding herds mated to yearling or 2-yr old bulls were used in this study. The breed groups of bulls were Hereford and Beef Synthetic and cow herds were Hereford, Hereford cross and Beef Synthetic, respectively. A week before the start of the breeding season the bulls were scored for libido, their scrotal circumferences were measured and semen samples were collected. Semen volume, sperm motility and percent normal cells were evaluated. The average bull to cow ratio was 1:20. Pregnancy rate increased as age and body weight of cows increased, but it was independent of the previous calving date. Calving date was not related to body weight or age of cow, but it was influenced by the previous calving date. Each day delay in calving after the first 5 wk of calving season resulted in a 0.7-day delay in the date of calving during the next calving season. The Beef Synthetic-sired herds had higher pregnancy rates (P < 0.05) than the Hereford-sired herds, but the average calving dates of the two groups were similar. Cows mated to 2-yr-old bulls had 5% higher (P = 0.12) pregnancy rate than those mated to yearling bulls. Five of the herds showed low fertility and late calving, probably due to low fertility of the bulls. Yearling weight and feedlot average daily gain were positively (P < 0.05) related to bull fertility. The number of services performed by a bull during a 10 min libido test and total libido score were also found to be useful in assessing bull fertility, but scrotal circumference or semen traits were not related to fertility of bulls when used in single-sire mating at pasture. Key words: Beef cattle, bull fertility, single-sire mating
THE ACCUMULATIVE EFFECT OF FINNSHEEP BREEDING IN CROSSBREEDING SCHEMES: GROWTH AND CARCASS TRAITS
Authors: FAHMY MOHAMED H.
Published: March 2010

Entire male lambs born in 1980 and 1981 were fed ad libitum for 8 wk a ration of grass and legume silage supplemented with grain mixture. The lambs represented the DLS breed (Dorset-Leicester-Suffolk) and six of its crosses with the Finnsheep rams (F) ranging from 1/8F to 6/8F. The lambs were slaughtered at about 43 kg liveweight and measurements of length, heart girth and circumference of leg were taken on the chilled carcasses. The carcasses were then divided into leg, loin-rack and shoulder cuts and each was expressed as a percentage of the whole weight. Kidney and pelvic fat were separated and weighed. The 12th rib cut was dissected into fat, bone and muscle and the percentage of each was calculated. The area of the two loin-eye muscles of the 12th rib and three measurements of backfat over that muscle were measured and averaged. The percent fat in the loin-eye muscle was determined by ether extraction. Birth weights were heaviest in DLS and 1/8F (P < 0.01) and decreased with the increase in the Finn proportion in the cross. At weaning (adjusted for 70 days) the 4/8F cross was the heaviest (23.2 kg) whereas the 6/8F was the lightest (20.2 kg). Little difference was observed between genetic groups in feed conversion. However, 6/8F and 5/8F groups made the fastest gain on test (P < 0.01). There was a difference between years in the gain made during the 8-wk feeding test probably as a result of changes in the feeding levels. The differences among genetic groups in age at slaughter were nonsignificant. The Finn crosses had generally longer and deeper carcasses than the DLS which in turn showed more leg development than most crosses. Although dressing percentage increased slightly with the increase in Finn proportion, it was relatively low ranging from 41.2 to 44.1%. DLS and 1/8F lambs had higher percentages of leg and lower percentages of shoulder than crosses with high Finn proportions. These latter had higher percentage of kidney fat. DLS lambs had higher percentages of lean and bone and lower percentages of fat in the 12th rib than the Finn crosses. They also had a larger area of loin-eye than most crosses and thinner backfat than all crosses. The only characters which showed a linear trend with the increase in Finn proportion were those related to body fat deposition. Key words: Finnsheep crosses, growth, carcass traits, DLS sheep
EFFECTS OF ZERANOL ON WEIGHT GAIN, BONE GROWTH AND OTHER CARCASS TRAITS IN STEERS AND BULLS
Authors: CHAUDHARY Z. I. , PRICE M. A. , MAKARECHIAN M.
Published: March 2010

The effects of zeranol were studied in 24 steers and 24 bulls starting at an average weight of 200 kg for a trial period of 183 days. Bulls grew faster than steers (P = 0.07) and zeranol-treated cattle showed higher average daily gain than controls (P < 0.05); there was no significant interaction between gender and treatment. Castration increased carcass fatness (P < 0.01) and decreased dressing percent (P < 0.01), rib-eye area (P < 0.01), shank muscle (P < 0.01) and shank muscle:bone ratio (P < 0.01). Implantation with zeranol had no effect on these traits. The weights of the radio-ulna, metacarpal and metatarsal bones were not significantly affected by gender or treatment. Growth at the distal end of the radius during the last 2 mo of the experiment was significantly less in treated cattle than in controls (P < 0.01) and in steers than in bulls (P < 0.01). Zeranol resulted in larger pelvic openings (P < 0.01) in bulls and steers and reduced libido (P < 0.05) in treated bulls. Key words: Cattle, zeranol, bone growth, castration, carcass traits, sexual development
EFFECT OF ACCLIMATION TO HIGH NITRATE INTAKES ON SOME RUMEN FERMENTATION PARAMETERS IN SHEEP
Authors: ALABOUDI A. R. , JONES G. A.
Published: March 2010

Four sheep, fed a basal diet which included 44% cereal grain and 50% hay and which was supplemented with KNO3, were progressively acclimated to a KNO3 intake of 2.5 g∙kg body wt−1∙day−1. Nitrate and nitrite reducing activity in strained rumen fluid (SRF) collected 2 h after feeding showed maximum values of 45.3 μg N∙mL−1∙h−1 and 39.4 μg N∙mL−1∙h−1, respectively, at an intake of 1.5 g∙kg body wt−1∙day−1. The rate of nitrate reduction was threefold higher (P < 0.01), and that of nitrite reduction fivefold higher (P < 0.01), than in SRF from sheep not receiving KNO3. When the KNO3 supplement was withdrawn the reducing activities fell to their initial levels within 3 wk. In a second experiment, nitrate, nitrite and volatile fatty acids in SRF, and methemoglobin in peripheral blood, were estimated at 30-min intervals after feeding in four sheep, two of which received 1.5 g KNO3∙kg body wt−1∙day−1. In the animals fed KNO3 the peak concentration of nitrate in SRF (13.30 μg NO3−–N∙mL−1) was reached 30 min after feeding, and that of nitrite (2.90 μg NO2−–N∙mL−1) 60 min after feeding; the presence of nitrate in SRF was associated with an increase in the molar proportion of acetate (P < 0.01) and a decrease in the proportion of n-butyrate (P < 0.01). The blood methemoglobin concentration did not exceed 2% (wt/wt) of total hemoglobin at any sampling time. In these animals 30–35 g KNO3 cleared the rumen within 3 h after feeding with no symptoms of nitrate toxicity. Enumeration of rumen bacteria by a direct isolation procedure indicated that the proportion of nitrate reducers in SRF was threefold higher (P < 0.01) in acclimated animals than in control animals. It was concluded that safe acclimation of sheep to high levels of dietary nitrate involved an increase in the rates of nitrate and nitrite reduction in the rumen, a narrowing of the ratio of these activities, and an increase in the proportion of nitrate reducing rumen bacteria. The residual effect of nitrate on the fermentation following clearance from the rumen was short-lived. Key words: Rumen fermentation, sheep, nitrate toxicity, nitrate reduction, nitrite reduction, rumen bacteria
GEOGRAPHICAL VARIABILITY OF THE ZINC, MANGANESE AND IRON CONCENTRATIONS OF FORAGES GROWN IN NORTHWESTERN MANITOBA
Authors: BOILA R. J. , DEVLIN T. J. , DRYSDALE R. A. , LILLIE L. E.
Published: March 2010

From two or three sites per township (93.24 km2), in the cattle-producing area of Northwestern Manitoba, 612 grass and 271 legume samples were collected and analyzed for zinc (Zn), manganese (Mn) and iron (Fe). Analyses were reported on an air-dry basis of approximately 90% dry matter. Within subregions, the mean Zn concentration ranged from 18.6 to 22.0 mg/kg and the mean Mn concentration ranged from 24.1 to 45.1 mg/kg for grass samples. The mean concentrations for the legume samples ranged from 17.8 to 25.5 mg/kg for Zn and 15.6 and 25.6 mg/kg for Mn. The mean Zn content in the legume samples was 3–5 mg/kg higher (P < 0.05) than that of the grass samples in three of seven subregions. In six of seven subregions the mean Mn content was 5–10 mg/kg higher (P < 0.05) in the grass than the legume samples. The range of Fe concentration was 31.3–1044.5 mg/kg for grass and 29.8–617.2 mg/kg for legume samples. Mean Fe for the entire study area was 107.6 and 93.6 mg/kg for grass and legume samples, respectively. For grazing cattle in Northwestern Manitoba, forages were deficient in Zn and Mn to varying degrees, with excessive intakes of Fe through soil contamination of forages possible. Recommendations for supplemental Zn and Mn should apply to the entire study area, and be based on the difference between the mineral content of forages and the requirement of cattle. Key words: Cattle, forage, minerals, zinc, manganese, iron
THE EJECTION OF A FROTHY FLUID FROM THE CLOACAL REGION OF ROOSTER DURING MANUAL SEMEN COLLECTION
Authors: FUJIHARA N. , KOGA O. , NISHIYAMA H.
Published: March 2010

The ejection of a frothy fluid from the rooster cloaca was observed during the collection of semen by the conventional manual method. The production of the frothy fluid was confirmed to be related to the tumescent portion of the dorsal cloaca, i.e. glandula proctodealis dorsalis (GPD), and the GPD was considered to be homologous to the triangular fold (TF) in the corresponding region of the male turkey cloaca. Electrical cauterization of the GPD led to a complete cessation of the ejection of a frothy fluid. Key words: Frothy fluid, cloaca, rooster
A COMPARISON OF ISOTOPE DILUTION AND WEIGH-SUCKLE-WEIGH METHODS FOR ESTIMATING MILK INTAKE BY PIGS
Authors: PETTIGREW J. E. , SOWER A. F. , CORNELIUS S. G. , MOSER R. L.
Published: March 2010

Isotope dilution estimates of milk consumption were 11.9% lower when weigh-suckle-weigh estimates were being made, suggesting that disruption of piglets and sows caused by the weigh-suckle-weigh method reduced milk consumption. Without correction for metabolic and salivary losses, the weigh-suckle-weigh method underestimated consumption. Key words: Piglet, sow, milk intake, milk production, weigh-suckle-weigh, deuterium oxide
ANIMAL PRODUCTS AND DEGENERATIVE DISEASE
Authors: KRITCHEVSKY DAVID
Published: March 2010

There is little argument concerning blood cholesterol as a risk factor for coronary heart disease, but considerable controversy regarding the influence of diet on blood cholesterol. All dietary components can affect cholesterolemia. Fats of animal origin are more saturated than corn or safflower oils, but the saturated vegetable fats (coconut and palm oils) are the most cholesterolemic. Cocoa butter is a highly saturated fat but its high content of stearic acid renders it much less cholesterolemic than would be expected. Animal protein, fed as the only source of protein, is more cholesterolemic than vegetable protein, but an equal mixture of the two is not cholesterolemic. The type of fat or fiber in the diet also influences its cholesterolemic effect. These data point up the importance of considering nutrient interactions. In the area of diet and cancer, rats fed saturated fat exhibit fewer chemically-induced tumors than do those fed unsaturated fat. Caloric restriction will inhibit carcinogenesis in rodents regardless of the type or amount of fat present in the diet. The observation that excessive caloric intake increases mortality was made by Lucretius in 50 B.C. It may be as true 2000 years later. Key words: Animal protein, cholesterol, experimental carcinogenesis, heart disease, lipoproteins
TRENDS IN CONSUMPTION OF ANIMAL PRODUCTS IN CANADA
Authors: STEWART LYNN , ROBBINS LINDA
Published: March 2010

Statistics Canada Apparent Food Consumption data (1963–1984) and Family Food Expenditure survey data (1974, 1978 and 1982) indicate that there has been a decline in consumption of certain animal products such as red meats, eggs, whole milk and animal fats. Generally, these are the foods consumers perceive to be relatively high in saturated fat and/or cholesterol. In contrast, apparent consumption of chicken, cheeses, partly skimmed milk, yogurt and vegetable fats has been increasing. Although health concerns have had a significant influence on animal-product consumption trends in Canada, there are many other factors underlying consumer behavior. Reasons for the observed consumption trends as well as possible implications for the marketing of animal products are discussed. Key words: Meat, beef, pork, fish, poultry products, dairy products
EFFICACY OF INSECTICIDAL EAR TAGS ON FLY CONTROL AND MILK PRODUCTION OF DAIRY COWS
Authors: BLOCK ELLIOT , LEWIS DAVID J.
Published: March 2010

Twenty Holstein cows were blocked into two groups of 10 cows each to evaluate an insecticidal ear tag (8% fenvalerate) on fly control and milk production. One group received one tag in each ear while the control group remained untagged. Each group was allowed access to an exercise-pasture lot of similar size. Forages were fed in the lots and grain was fed in the barn at milking. Tagging resulted in a 99.9% reduction in horn flies over the 16 wk of the trial. However, other flies (house, stable and face) were not controlled to the same extent. As horn fly numbers decreased the number of the other flies increased on tagged cows. Tagging resulted in an overall increase in milk yield by 1.06 kg/d for the trial but not all weeks of the trial showed significant responses. Milk fat and protein percentages were not different between tagged and control animals. Key words: Diptera, dairy cattle, milk production, fenvalerate, ear tags, fly control
RELATIONSHIPS OF REPRODUCTION TRAITS, BODY WEIGHT AND MILK YIELD IN DAIRY CATTLE
Authors: BATRA T. R. , LEE A. J. , McALLISTER A. J.
Published: March 2010

The relationships between reproduction traits, body weight and milk yield were investigated using data from 1611 heifers and 733 cows from two lines of the National Cooperative Dairy Cattle Breeding Project. The data were analyzed separately for heifers and cows within lines using a mixed linear model containing fixed effects for station, year of birth, season of birth and random effect of sires. Heritability estimates and genetic correlations were estimated by a paternal half-sib analysis. Heritability estimates for heifer and cow reproduction traits ranged between 0 and 26% while those of body weights at calving and 112 d postpartum and milk yield ranged from 24 to 43%. Heifers with difficult calving had a higher incidence of retained placenta than those with normal calving. Phenotypic correlations between heifer reproduction traits and milk yield during first lactation were small. High milk production in cows was associated with longer calving interval. Phenotypic correlations between heifer's and cow's reproduction traits were small. Difficult calving in heifers impairs reproductive performance after calving resulting in greater number of days from calving to first and last breeding and leading to a longer calving interval. Key words: Reproduction traits, heifers, cows, milk yield, dairy cattle
SERUM ANDROGEN AND GONADOTROPIN PROFILES OVER THE FIRST YEAR OF LIFE IN RAM LAMBS AND THE EFFECT OF SEASON OF BIRTH
Authors: COOK SUSAN J. , RAWLINGS N. C.
Published: March 2010

Testosterone (T), dihydrotestosterone (DHT), androstenedione (D), androsterone (A), 5α-androstane-3α, 17β-diol (3α-diol), 5α-androstane-3β, 17β-diol (3β-diol), LH and FSH were measured in serum from rams over the first year of life. March-born rams had higher mean serum LH levels than July-born rams, but mean serum FSH levels were higher in July-born rams. In March- and July-born rams, gonadotropin levels rose at 40–60 d of age and then declined. In all rams, serum concentrations of androstenedione (D) and the 5α-reduced androgens fell into a similar range, but were present at lower concentrations than T. In March-born rams, only serum levels of T, D and DHT changed significantly with time, rising to a peak at 200–240 d of age and then declining. Only serum levels of T rose significantly with time in July-born rams, but not to the extent seen in March-born rams. Over the first year of life mean levels of DHT, 3α-diol and A were higher in July-born rams than March-born rams, while levels of 3β-diol were higher in March-born rams. Mean levels of D did not differ between the groups. Key words: Ram lamb, androgens, LH, FSH
NEAR INFRARED REFLECTANCE SPECTROSCOPY FOR PREDICTING FORAGE COMPOSITION AND VOLUNTARY CONSUMPTION AND DIGESTIBILITY IN CATTLE AND SHEEP
Authors: REDSHAW E. S. , WEISENBURGER R. D. , MATHISON G. W. , MILLIGAN L. P.
Published: March 2010

Near infrared reflectance spectroscopic (NIR) measurements were made on 82 samples of legume (alfalfa and clover), grass (brome, timothy, reed canary grass and meadow foxtail) and legume-grass mixtures using a Neotec model 6100 scanning monochromator. Data on the forages, used for establishing NIR calibrations for predictive relationships and appraising them, were chemical composition and measurements of digestibility and voluntary consumption for cattle and sheep. The primary wavelengths selected by multiple regression techniques were similar to those obtained by other researchers for crude protein, acid and neutral detergent fiber, calcium and phosphorus. Similar primary wavelengths were selected for prediction of digestibility and voluntary intake (g kg−0.75) of forages for cattle and sheep, but those selected for voluntary intake on the basis of percentage of body weight differed between animal species. The wavelengths which best predicted animal intake and digestibility in our trials differed from those reported by other researchers. Crude protein, acid detergent fiber, neutral detergent fiber, lignin, acid detergent insoluble nitrogen, calcium, phosphorus and ash concentrations in forage were predicted with standard errors of 1.0, 2.2, 2.9, 1.1, 0.07, 0.15, 0.02, and 1.2%, respectively. The accuracy of predictions for these chemical constituents was similar to that reported by other workers. Digestible energy content, dry matter digestibility, voluntary intake and digestible energy intake of hays by cattle were predicted with standard errors of prediction of 0.59 MJ kg, 2.4%, 7.6 g DM kg−0.75, and 79 kJ kg−0.75, respectively. Corresponding values for sheep were 0.96, 4.4, 6.3 and 128. The quantitative importance of variability in animal data in the calibration of the NIR procedure was discussed. This variability accounted for about one-half of the variability of NIR prediction of voluntary DM and digestible energy intake of cattle. This proportion was reduced to approximately one-quarter and one-sixth for digestibility of dry matter and digestible energy content of feed, respectively. Key words: Cattle, sheep, forages, near infrared reflectance spectroscopy, nutritive value
EFFECT OF LASALOCID, MONENSIN AND THIOPEPTIN ON LACTATE PRODUCTION FROM IN VITRO RUMEN FERMENTATION OF STARCH
Authors: NAGARAJA T. G. , GALITZER S. J. , HARMON D. L. , DENNIS S. M.
Published: March 2010

Starch fermentations with strained rumen fluid and centrifuged rumen fluid devoid of protozoa were set up to test the effect of lasalocid, monensin, and thiopeptin on L(+) and D(−) lactate production. Protozoa-free rumen fluid was the supernatant from low-speed centrifugation of strained rumen fluid. Starch fermentation in the control (no antibiotic) with centrifuged rumen fluid resulted in higher lactate concentration than the fermentation with strained rumen fluid. Decreased lactate production with strained rumen fluid was attributed to sequestration of starch by protozoa and to enhanced lactate fermentation. Addition of lasalocid or monensin (1.5–48.0 μg mL−1) to the fermentation enhanced L(+) and D(−) lactate production in the presence of protozoa. In the absence of protozoa, lasalocid and monensin inhibited L(+) lactate production; however, D(−) lactate concentration was unaffected. Increased lactate production by lasalocid and monensin in the presence of protozoa was possibly due to inhibition of protozoal engulfment of starch. Thiopeptin had no effect on lactate production in the presence of protozoa but in the absence of protozoa lactate production was inhibited. Similar antibiotic responses were observed at different starch amounts (0.5, 1.5 and 3.0 g) and with starch types (soluble, corn and wheat) and with rumen fluid collected from defaunated cattle. Key words: Antibiotics, cattle, rumen, starch, fermentation, lactic acid
GROWTH, FEED UTILIZATION AND CARCASS QUALITY RESPONSES OF PIGS FED FROST-DAMAGED CANOLA SEED (LOW-GLUCOSINOLATE RAPESEED) AS AFFECTED BY GRINDING, PELLETING AND AMMONIATION
Authors: BELL J. M. , KEITH M. O.
Published: March 2010

Canola seed (CS) having 20, 45 and 65% frost damage was fed at dietary levels up to 30% to 144 pigs of 23 ± 1 kg initial weight to determine the effects of processing on feeding value. In exp. 1, 10, 20 and 30% levels of each lot of CS were fed to barrows (M) and gilts (F) up to 100 kg liveweight. Average daily gain (ADG) increased with increasing frost damage (0.75, 0.77, 0.78 kg). Similarly, feed intake (FI) increased (2.19, 2.27 and 2.35 kg day−1). Feed-adjusted ADG were equal. ADG and FI were reduced at the 30% level in diet compared with 10%. A palatability effect is postulated. Glucosinolate levels declined with increasing frost damage. In exp. 2, 45% frost-damaged CS was fed at 30% of the diet to M and F pigs up to 57 kg liveweight to compare whole vs. ground CS, fed as meal or pellets. Grinding depressed FI but not ADG. Pelleting improved ADG but not FI. Both processes improved feed:gain ratio. In exp. 3, diets containing 45% frost-damaged, ground CS, with and without ammoniation (0.5% NH3), were compared with a control diet supplemented with soybean and canola meals by feeding to M and F pigs up to 100 kg liveweight. ADG and FI of pigs fed CS were below both the controls and pigs fed the ammoniated CS. Ammoniation had minor effects on amino acid and available lysine content but improved FI and ADG. Carcass index values were unaffected by either level or treatment of CS. Key words: Rapeseed, canola, processing, feeding trials, pigs, freezing
EFFECTS OF FEEDING SPENT BLEACHING CLAY FROM CANOLA OIL REFINING TO GROWING MICE AND RATS
Authors: KEITH M. O. , BELL J. M.
Published: March 2010

The spent bleaching clay from canola (rapeseed) oil processing might be a useful ingredient in livestock feeds but little is known about possible metabolic effects of the clay. Experiments with growing mice and rats were designed to study effects of spent clay on weight gains, feed utilization and gross anatomy. In exp. 1 clay was mixed 1:1 with cornstarch or canola meal. These premixes were incorporated into purified and natural ingredient diets to provide clay levels of 0, 0.3, 0.6, 1.2 and 2.4%. Eighty weanling mice were randomly allotted to the 20 diets which were fed for 28 d. Liver weights and liver: body weight (%) increased (P < 0.05) with increasing levels of clay fed in purified diets. Otherwise clay treatments had no effect on the responses:weight gain, feed:gain ratio, plasma urea nitrogen or kidney weights. Experiment 2 involved weanling rats fed three different clay samples at dietary levels of 1, 2 and 4%, with and without an antioxidant (ethoxyquin) for a 28-d period. Using the same criteria as in exp. 1, clay samples, levels and use of antioxidant had no effect on animal responses. The data demonstrated that up to 4% spent bleaching clay could be included in natural ingredient diets without either beneficial or harmful effects to growing mice and rats. Key words: Spent bleaching clay, mice, rats, feeding trials, bentonite, rapeseed