bluuebunny/crossref_metadata_2025 huggingface dataset:
CONTROLLED BREEDING IN CATTLE: A REVIEW
Authors: MANNS J. G. , HAFS H. D.
Published: March 2010

The use of progeny-tested sires through artificial insemination (AI) is an important tool for genetic improvement in cattle. Use of AI in beef cattle and dairy heifers is generally not practical because of difficulties associated with estrus detection. This situation will change only if breeding by AI can be done under controlled conditions, preferably an insemination at a fixed time relative to a treatment. Sufficient data on hormone secretion patterns during the cycle of the cow are available to provide a reasonably detailed understanding of hypothalamic–pituitary–ovarian interrelationships. Two methods, although both are at the development stage, are providing encouraging results. Much of the early work using natural and synthetic progestogens orally or by injection was disappointing because fertility was depressed after treatment. However, by reducing the period of treatment to 9 days and combining the synthetic progestogen implant with an injection of estrogen plus progestogen, it has been possible to get good synchrony and apparently normal fertility. Further studies need to be conducted to verify that fertility is normal and to determine if a single timed insemination relative to time of implant withdrawal would give normal fertility. A second method is based on use of potent luteolytic agents. Prostaglandin F2α (PGF2α) or synthetic analogues act by causing regression of the corpus luteum when they are injected between about days 5 and 18 of the cycle. Animals with a functional corpus luteum will come into estrus about 72 h after the injection and will ovulate about 23 h after that. Since injections of PGF2α are ineffective during the remainder of the cycle, a single injection can not provide complete synchrony. Two injections of PGF2α at 10- to 12-day intervals should in theory give complete synchrony since all cycling animals would have a functional corpus luteum at the second injection. This theory appears to be valid and fertility with a single (80 h) or double (70 and 88 h) insemination is comparable to normal.
STORAGE OF MAMMALIAN OOCYTES AND EMBRYOS: A REVIEW
Authors: MAURER RALPH R.
Published: March 2010

This article reviews the literature on storage of mammalian oocytes and embryos. Preimplantation embryos have been stored in vitro, in ligated oviducts and uteri of donor females, or in ligated oviducts of heterogenous females, and developed to term following transfer to suitable recipients. Embryo viability declined markedly after 48 h in storage anywhere other than in the reproductive tracts of species in which delayed implantation occurs naturally. Embryos stored at 0–37 C retained viability for 120 h; thereafter viability decreased. Storing oocytes in vitro at 10 C prolonged fertilizability for up to 3 days, but none developed to term if fertilized after 31 h storage. For successful storage, both cleavage and metabolism of embryos must be inhibited completely. This inhibition was accomplished with mouse and rabbit embryos by using dimethyl sulfoxide (DMSO) as the cryoprotective agent, slow rates of cooling (0.3–2 C/min) and warming (3–25 C/min), and a stepwise dilution of DMSO immediately after thawing. Neonates have resulted from the transfer of embryos previously frozen for 222 days.
FATE OF THE SILICA IN PRAIRIE HAY AND ALFALFA HAY CONSUMED BY CATTLE
Authors: BAILEY C. B.
Published: March 2010

Each of three rumen-fistulated cows was fed prairie hay at 5.5, 7.3, or 9.1 kg/day during three consecutive 2-wk periods and then the same amounts of alfalfa hay for a second series of 2-wk periods. The prairie hay contained 5.7% silica and the alfalfa hay contained 0.4% silica. Reticulo-rumen fluid was saturated with silicic acid at all levels of intake of prairie hay but was unsaturated at all levels of intake of alfalfa hay, though the concentration increased with increasing intake. The concentration did not vary with time after the feeding of either type of hay. Output of silicic acid in urine tended to increase with increasing intakes of either type of hay. The concentration of silicic acid in blood plasma was higher with prairie hay than with alfalfa hay but was unaffected by level of hay intake. Neither type of hay nor level of intake affected the concentration of silicic acid in saliva. In a second experiment, silicic acid concentration in the reticulo-rumen fluid of cows on alfalfa hay was shown to be unrelated to water intake. In both experiments, the rate of excretion of silicic acid in urine of cows on alfalfa hay closely paralleled the concentration of silicic acid in reticulo-rumen fluid (r = 0.94). Estimates derived from the results of these experiments indicate that 7% of the silica in prairie hay and 16% of that in alfalfa hay was taken into solution in reticulo-rumen fluid and thus made available for absorption. Of these amounts, not more than 12% was absorbed with a diet of prairie hay and up to 45% may have been absorbed with a diet of alfalfa hay. Excretion of silicic acid was between 60 and 75% of that absorbed on the prairie hay diet and between 40 and 60% of that absorbed on the alfalfa hay diet.
LIQUID DIETS CONTAINING POULTRY WASTES FOR RUMINANTS
Authors: McNIVEN MARY , SUMMERS J. D. , LEESON S.
Published: March 2010

Mature sheep were fed a control corn–soybean meal diet, the same diet mixed with water to give a dry matter:water content ratio of 1:4, or a corn–wet, caged layer manure (CLM) diet containing 80% moisture. Digestible dry matter, nitrogen and energy were highest for the liquid control diet. The CLM diet gave results comparable to that of the dry control diet. Feeding the same diets to growing lambs confirmed the superiority of the liquid control diet as compared to the same ration fed in the dry form. Weight gain and feed:gain ratio were superior for the CLM diet as compared to the dry control.
NUTRITIVE VALUE OF BROKEN RICE AND GROUND FLINT CORN FOR YOUNG PIGS AND RATS
Authors: McKINNON P. J. , BOWLAND J. P. , RATARASARN SUCHEEP
Published: March 2010

Fifty-two litters involving 380 pigs from Duroc (D), Landrace (L) and D × L breed groups were used in one experiment and 12 rats in another to assess the nutritive value of broken rice and corn as energy sources in starting diets of pigs from 3 to 10 wk of age and in diets of rats from 21 to 49 days of age. Dietary treatments in the pig experiment consisted of either broken rice, corn, or a broken rice/corn mixture (1:1) as the major ingredients or a control diet based on corn and soybean meal with 20% dried skim milk. Similar diets based on broken rice, corn or the mixture were used in the rat experiment. No significant differences were found during the pre-weaning period, but postweaning body weight at 8 and 10 wk of age, feed consumption and rate of gain were significantly (P < 0.05) greater for pigs fed the control diet. Rate of gain was significantly (P < 0.05) less and feed:gain ratios were significantly (P < 0.05) greater for broken rice than other diets in the pig experiment. Digestibility of energy was greater for broken rice than for other diets but digestibility of nitrogen was low for all diets. Lower feed intake and daily gain of pigs from Duroc and crossbred gilt breed groups was noted compared with pigs from Landrace or crossbred sow groups. No significant differences between dietary treatments were noted in the rat experiment. Digestible energy was estimated for all diets at 3,300–3,400 kcal/kg for pigs and 3,500–3,550 kcal/kg for rats.
NITROGEN ADDITIVES TO CORN SILAGE FED TO GROWING CALVES
Authors: MOWAT D. N. , BUCHANAN-SMITH J. G. , MACLEOD G. K. , CORE J. E.
Published: March 2010

Three separate experiments were conducted to investigate performance of light-weight calves fed corn silage supplemented with different non-protein nitrogen (NPN) sources added at ensiling time. In one experiment NPN was also added at feeding time. For calves up to approximately 290 kg body weight all supplements containing only NPN reduced weight gains by approximately 0.10–0.15 kg/day compared to soybean meal or low-urea supplements. Corn silage treated with NPN silage additives resulted in reduced dry matter intake compared to soybean meal supplementation. Thus, the effect on feed efficiency was not as great as on weight gains. Treated silages tended to be higher in pH and lactic acid but lower in acetic acid content. A large portion of the NPN added at ensiling time was analyzed as ammonia in the silages. Also, true protein content of the treated silages tended to be higher than that of the controls.
COMPARISON OF SEVERAL EGGSHELL CHARACTERISTICS WITH IMPACT RESISTANCE
Authors: VOISEY PETER W. , HUNT J. R.
Published: March 2010

Precise measurements of eggshell resistance to impact fracture were compared with 11 other measurements used to predict shell quality. Shell weight per unit area provided the best prediction, whereas Beta backscatter readings and egg weight were not useful indices of shell strength. Shell deformation and egg specific gravity appeared to be useful non-destructive prediction techniques. However, none of the characteristics, singly or in combination, provided a precise prediction of resistance to impact. It was concluded that only direct determination of the force to break the shell had the potential to precisely measure shell resistance to damage. The force required to fracture eggs under impact was higher than under quasistatic compression. This confirmed that the shell material is strain–rate sensitive.
QUALITY OF PROTEIN IN MILK REPLACERS FOR YOUNG CALVES. I. FACTORS AFFECTING IN VITRO CURD FORMATION BY RENNET (CHYMOSIN, RENNIN) FROM RECONSTITUTED SKIM MILK POWDER
Authors: EMMONS D. B. , LISTER E. E.
Published: March 2010

Fresh milk coagulates with chymosin (rennin) in the calf stomach to form relatively strong curds. With respect to calf milk replacers it is of interest to study factors affecting curd formation of reconstituted skim milk powder by this enzyme. Curd firmness was increased by lower pH of the skim milk over a range of 5.6–6.6, higher concentration of skim milk solids over a range of 5–20%, higher concentrations of chymosin, lower temperatures of heat treatment of skim milk prior to spray drying, and higher temperature of coagulation, 37 vs. 30 C. Reconstitution of powder in water above 56 C for 2 min remarkedly reduced the firmness of the curd. The following coagulation conditions were selected for comparison of powders and milk replacers: addition of 1 ml of a 1:50 dilution of standard strength commercial rennet to 100 ml of milk previously adjusted to pH 6.1, 10% of nonfat solids in the aqueous nonfat phase, temperature of 37 C, and measurements of firmness 30 min after adding rennet. Commercially produced skim milk powders designated high-heat, medium-heat and roller products yielded soft curds. Commercial low-heat powders yielded strong curds. All coagulated in less than 4 min at pH 6.1, the time being relatively independent of heat treatment.
EFFECTS OF AMMONIUM CHLORIDE ON FORMATION OF SILICEOUS URINARY CALCULI IN CALVES
Authors: BAILEY C. B.
Published: March 2010

not available
DIGESTION OF NUTRIENTS IN THE SMALL INTESTINE OF PIGS FED DIETS CONTAINING RAW AND AUTOCLAVED FABA BEANS
Authors: IVAN M. , BOWLAND J. P.
Published: March 2010

Four castrated pigs, each fitted with a re-entrant cannula in the terminal ileum, were used to study digestion in the small intestine. A nitrogen-free diet was used for the estimation of metabolic nitrogen and amino acids. Faba beans, as the sole source of dietary protein, were used raw or after autoclaving for 30 or 60 min. The four diets were fed to the pigs in a 4 × 4 latin square experiment. The pigs were fed each diet for 6 days prior to a 24-hr collection of total ileal contents. Autoclaving of faba beans had no significant effect on digestibility of dry matter, gross energy, nitrogen and individual amino acids except arginine, which was significantly increased. The intestinal uptake of arginine was the highest and of cystine the lowest in all faba bean diets. It was concluded that autoclaving faba beans had no beneficial effect on the digestion of nutrients in the small intestine of the pig.
INDUCTION OF CYCLIC ACTIVITY IN THE EARLY POSTPARTUM DAIRY COW
Authors: MANNS J. G. , RICHARDSON G.
Published: March 2010

Twenty-five lactating dairy cows were treated with either saline (control), 500 μg gonadotropin-releasing hormone (GnRH), GnRH + 10 mg estradiol 17β (E2), E2, or GnRH + E2 + 25 mg prostaglandin F2α (PGF2α) at approximately 11 days postpartum. Blood samples were taken at the time of injection and then twice each week for about 30 days. Treatment with GnRH alone gave the largest LH peak; LH production appeared to be inhibited when E2 was given with GnRH. Plasma estrogen concentrations were above 1 ng/ml for 12 h in all animals receiving estrogen alone or in combination. None of the treatments hastened initiation of cyclic activity which began at an average of 19 days postpartum. It seems unlikely that postpartum anestrus is an important constraint to early rebreeding in dairy cows.
DIGESTIBILITY AND FEEDING VALUE OF HULLESS BARLEY FOR PIGS
Authors: MITCHALL K. G. , BELL J. M. , SOSULSKI F. W.
Published: March 2010

A feeding trial and two digestibility trials were conducted to evaluate two isogenic lines of regular (covered) and hulless barley, cvs. Compana and Vantage, compared also with wheat. Eight pigs (4♀, 4♂) were fed each diet over the weight range 22–50 kg. Half of the pigs, randomly selected within sex and diet groups, were used in the digestibility trials, employing chromic oxide markers. The second digestibility trial involved different pigs from the first and a new source of hulless barley. The average daily gain was 0.62 kg and there were no significant differences between rations. Likewise, feed intakes and efficiencies of feed conversion revealed no treatment differences. The digestibility of protein in hulless barley was lower than in regular barley (70 vs. 73% in one trial, 74.8 vs. 79.3% in another) and both types of barley were lower in protein digestibility than wheat (81.4%). Energy digestibility was highest in hulless barleys (77.3 vs. 73.2; 81.8 vs. 77.1%). Hulless barley contained about 5% more digestible energy than regular barley (3,295 vs. 3,133 kcal/kg) and the same digestible crude protein (12.85 vs. 12.90%).
FEEDING HABITS OF MULE DEER ON FALL, WINTER, AND SPRING RANGES NEAR KAMLOOPS, BRITISH COLUMBIA
Authors: WILLMS W. , McLEAN A. , RITCEY R.
Published: March 2010

Diets of mule deer were studied in the Kamloops area from September to April. The forages of 67 rumen samples were sorted to grass, tree, shrub, and forb species and the percent oven-dry weights calculated for each. Polynomial regressions (to the third degree) were used to describe the use of each plant-growth form over time, as well as to determine the influence of snow depth on plant species consumption. Douglas fir formed most of the tree component of the diet of the deer. Consumption of this species was highest in December and January. Grass consumption was less than 10% until early spring when it increased to almost 100%. More forbs were consumed in fall than in winter, while shrubs were consumed more in early fall and late winter than in late fall. Species composition of each plant growth-form generally varied with season. Increasing snow depth altered the proportion of both small and large plants in the diet. As snow depth increased, fewer small plants but more large plants were consumed.
CARCASS CHARACTERISTICS AND PERFORMANCE OF LAYING BIRDS FED RAPESEED MEAL
Authors: LEESON S. , SUMMERS J. D. , GRANDHI R.
Published: March 2010

Diets containing up to 11% of rapeseed meal protein were fed to individually caged White Leghorn laying birds. Egg production, feed intake and body weight gain were less for birds fed rapeseed, rather than soybean meal. The reduction in body weight gain was associated with a reduction in carcass fat content, and an increase in carcass protein and moisture contents. Liver fat was also less for birds fed rapeseed meal. Results from amino acid supplementation studies indicated that the reduction in carcass fat deposition of laying birds fed RSM may be involved with dietary amino acid balance.
EFFECTS OF VARIOUS HEAT AND pH TREATMENTS ON DIGESTIBILITY OF PROTEIN IN PEA PROTEIN CONCENTRATE (PISUM SATIVUM)
Authors: CHOW C. , BELL J. M.
Published: March 2010

Pea protein concentrate (PPC) was subjected to various cooking and acid or alkali treatments in order to improve the digestibility of pea protein for use in calf milk replacers. Treatment effects were assessed by in vitro digestion with rennin, pepsin and calf abomasal fluids. Oven heating at 95–246 C for 5 min to 15 h or steam heating at 1.06 kg/cm2 for 4 h failed to improve digestibility. Treatment of PPC in an aqueous medium at pH values from 2 to 12 for 5 h at 37 C resulted in higher digestibility. A pH of 2.0 or 10.6 was most effective. Acid or alkali hydrolysis of PPC at 110 C for 4–5 h increased digestibility, but adversely affected amino acid content. Rennin was consistently less effective than pepsin or abomasal contents in digesting PPC. The pH of abomasal contents from young calves fed milk replacers may be too high for effective pepsin activity. These factors could account for the low digestibility of non-milk proteins by calves under 2 wk of age.
RESPONSE TO NONPROTEIN NITROGEN AND SULFUR SOURCES BY THE EARLY-WEANED CALF
Authors: WINTER K. A.
Published: March 2010

Sixty Holstein bull calves were used in two experiments to evaluate two nonprotein nitrogen sources and several sulfur sources in calf starter rations. Experiment 1 compared urea and biuret, with and without sulfur (S), methionine hydroxy analog (MHA), and S plus MHA; experiment 2 compared the effect of elemental sulfur and sodium sulfate added to a urea-supplemented starter on calf response to these feeds. Performance of calves on the biuret-supplemented starters was significantly reduced as compared with urea-supplemented starters. The addition of sulfur or MHA to the NPN-supplemented starters did not affect animal performance significantly. However, sulfur did tend to improve performance of the urea-fed calves and had the reverse effect when biuret was fed, while MHA tended to depress performance when urea was fed. In the second experiment, the addition of either sulfur or sodium sulfate to the urea-supplemented started did not significantly improve animal performance, even when 40% of the total protein in the diets was supplied by nonprotein nitrogen sources. The urea-supplemented starter rations were found to have N:S ratios before sulfur supplementation of 11.4:1 (experiment 1) and 9.4:1 (experiment 2), which are close to the ratios considered optimum for ruminants.
EFFECTS OF CREEP AND STARTER COMPOSITION ON FEED INTAKE AND PERFORMANCE OF YOUNG PIGS
Authors: OKAI D. B. , AHERNE F. X. , HARDIN R. T.
Published: March 2010

Two experiments were conducted to study the performance of 3- and 5-wk-weaned pigs fed creep or starter diets of differing complexity. In experiment 1, 36 litters, adjusted to seven or eight pigs per litter, were randomly allotted to four dietary treatments: no creep feed or ad libitum access to a feed of a simple, semi-complex or complex formulation during the pre-weaning period from 10 days of age until weaning at 3 wk of age. After weaning, pigs were paired by weight, within litters and treatments and each pair randomly allotted to one of the three diets. The post-weaning feeding period was from 3 to 7 wk of age. In experiment 2 the same creep and starter treatments as were used in experiment 1 were fed to 48 litters from 2 to 5 wk of age. After weaning, litter sizes were adjusted to seven or eight pigs and four litters from each pre-weaning treatment were allotted to each of the diets from 5 to 8 wk of age. In both experiments, creep feed intake was low for all three diets and though more of the complex diet was eaten in both experiments there were no significant differences in mean piglet weaning weight. In the post-weaning period, increase in diet complexity led to a corresponding increase in feed intake and weight gain. Only in the first experiment were the differences in post-weaning weight gain significant (P < 0.001). The digestibility coefficient for energy increased with an increase in diet complexity. Significant creep–starter interactions were only observed in the second experiment; the possible reasons for this have been discussed.
UREA DEGRADATION IN THE CAMEL
Authors: EMMANUEL B. , HOWARD B. R. , EMADY M.
Published: March 2010

Following a single injection of 14C-urea, the kinetics of urea metabolism have been studied in two female Arabian camels (Camelus dromedarius) fed roughage diets containing 6.1 (diet A), 9.6 (diet B), and 13.6% (diet C) crude protein. In general, plasma urea concentration, urea pool size, urea entry rate and urinary urea excretion rate increased as the dietary nitrogen intake increased. The mean extents of urea degradation were approximately 86, 74 and 47% for diets A, B, and C, respectively, as calculated from the ratio of urea degradation rate to urea entry rate, or from the fraction of 14C-urea recovered in the urine. The following parameters were linearly related: urea entry rate and urea pool size, urea pool size and plasma urea concentration, percentage urea degraded and urea entry rate, and percentage urea degraded and crude protein intake.
IN VITRO ORGANIC MATTER DIGESTIBILITY AS AFFECTED BY PELLETING OR CHOPPING THE DIET OF THE INOCULUM DONOR, DIFFERENT INOCULUM DONORS, OR WEEK OF FERMENTATION
Authors: KNIPFEL J. E.
Published: March 2010

not available
EFFECTS OF USING A HEATED, LITTERLESS FLOOR FOR REARING TURKEY BROILERS
Authors: PROUDFOOT F. G. , ALLABY S. F. , GUNN J. D.
Published: March 2010

Three experiments involving 3,000 turkey broilers were conducted to evaluate the feasibility of rearing turkey broilers on a heated litterless floor compared with rearing under a conventional brooder with planer shavings over a concrete floor. The results of these experiments provide evidence that it is feasible to use a hot-water-heated floor, with only a sprinkling of litter, for rearing turkey broilers if litter materials are expensive or difficult to obtain.
ESTRUS AND PREGNANCY IN PRIMIPAROUS SOWS TREATED WITH PREGNANT MARE’S SERUM GONADOTROPIN OR ESTRADIOL-17β AND PROGESTERONE
Authors: DYCK G. W.
Published: March 2010

Over a 3-yr period, the effectiveness of pregnant mare’s serum gonadotropin (PMSG-1,500 IU) or estradiol-17β (1 mg) plus progesterone (2 mg) for the stimulation of post-weaning estrus and conception in primiparous sows from a herd with a history of post-weaning anestrus was evaluated. On the day after weaning, an intramuscular (i.m.) injection of PMSG or steroids was given to 49 and 51 sows, respectively. Fifty untreated sows served as controls. Treated sows in estrus by day 8 and control sows in estrus by day 40 were bred on the 2nd day of estrus. Serviced sows were killed at day 25 of pregnancy or on the day after return to estrus. The remaining sows were killed when in estrus or between days 41 and 45 after weaning. By day 8, more (P < 0.01) PMSG-treated (98.0%) sows were in estrus than either the steroid-treated (64.7%) or control (66.0%) sows. By day 14, fewer (P < 0.05) steroid-treated than control sows were in estrus (64.7 vs. 82.0%). The mean interval between weaning and estrus for sows in estrus by day 8 was less for the PMSG (P < 0.01) - and steroid (P < 0.05) - treated sows than for the control sows (3.83 ± 0.11 and 4.36 ± 0.28 vs. 5.12 ± 0.23 days). For the steroid-treated and control sows in estrus after day 8, the mean time to estrus was 34.6 ± 3.5 and 21.2 ± 2.8 days, respectively (P < 0.01). Pregnancy rates were similar for the PMSG and steroid treatments (57.1 and 47.0%), and lower than for the control sows (84.0%). The PMSG-treated animals had larger litters (16.4 ± 1.0 embryos) than either the steroid-treated (12.8 ± 1.1 embryos) or control (11.3 ± 0.8 embryos) animals.
EFFECTS OF COLD ON DIGESTIBILITY, RETENTION TIME OF DIGESTA, RETICULUM MOTILITY AND THYROID HORMONES IN SHEEP
Authors: WESTRA R. , CHRISTOPHERSON R. J.
Published: March 2010

In the first of two experiments, 12 closely shorn yearling wethers received grass hay either in the long form or pelleted form and were acclimated to temperatures of 0.8, 10.1 and 17.7 C. Feed was provided for each treatment at an equivalent intake level of approximately maintenance. The sheep receiving long hay consumed less water than those receiving hay pellets. Water consumption decreased with decreasing temperature. The apparent digestibilities of DM, E, N and ADF were lower for the pelleted hay than for the long hay (P < 0.001). The digestibilities of DM, E and ADF were lower (P < 0.05) when the sheep were at 0.8 C than at 17.7 C, but there were no significant ration × temperature interactions. In the second experiment, six closely shorn sheep receiving a pelleted hay ration at the maintenance level were exposed for 4–6 wk to temperatures of 21.2 and 1.3 C. DM digestibility was reduced (P < 0.05) in the cold by 0.18 percentage units per degree (C) drop in temperature. Mean retention times, determined from the fecal excretion patterns of 144Ce following a single injection into the rumen, decreased (P < 0.05) from 38.5 h in the warm environment (21.2 C) to 32.5 h in the cold (1.3 C). The mean number of reticulum contractions per hour was increased (P < 0.001) from 60 at 21.2 C to 72.5 at 1.3 C. Serum thyroxine (T4) and triiodothyronine (T3) concentrations were significantly (P < 0.05) higher in sheep exposed to the cold compared to the sheep in the warm temperature treatment. It is concluded that pelleting hay does not alter the depressing effect of cold environmental temperatures on digestibility and that the effect of temperature on digestibility is likely due to a change in rate of passage of digesta through the altimentary tract.
RELATIONSHIP BETWEEN PEDIGREE INDEX AND PROGENY PERFORMANCE FOR CANADIAN DAIRY BULLS
Authors: STEWART H. M. , BURNSIDE E. B. , WEAVER G. B. , FREEMAN M. G.
Published: March 2010

Progeny performance was related to pedigree indexes for 216 Holstein bulls which entered Canadian Artificial Insemination units from 1962 to 1970. Progeny performance for body conformation (average point score) was related to pedigree index for point score, the sire’s point score proof, and an approximate index based on sire and material grandsire proofs at the time the bull entered the stud. Regression coefficients were 0.34 (±.07), 0.17 (±.14), and 0.32 (±.07), respectively. Regressions of progeny performance for Breed Class Average (BCA) milk (Herdmate Comparison) on pedigree index for BCA milk (Herdmate Comparison), the sire’s HMC index, and the approximate HMC index yielded coefficients of.70 (±.11),.44 (±.08), and.94 (±.15), respectively. In both cases, the pedigree index was the best indicator of progeny performance, followed by the approximate index and the sire’s index, respectively. As no Best Linear Unbiased Prediction (BLUP) pedigree index for BCA milk was available, progeny performance for BLUP proofs was related to pedigree index for milk (HMC), the sire’s BLUP proof and an approximate index based on the sire’s and maternal grandsire’s BLUP milk proofs. Regression estimates were.70 (±.10),.56 (±.08), and 1.16 (±.13). The approximate index was a better predictor of progeny performance (BLUP) than the pedigree index based on HMC milk proofs.
SOCIAL AND PHYSICAL ENVIRONMENTAL INFLUENCES ON CAGED SINGLE COMB WHITE LEGHORN LAYERS
Authors: SEFTON A. E. , CROBER D. C.
Published: March 2010

Pullets from two-way crosses between three highly inbred lines of Single Comb White Leghorns were housed in two sizes of commercial laying cages, two pullets per cage. Individual bird egg production records were kept when birds were 68–72 wk of age. During this period, peck order within each cage, fearfulness and body weight of each individual were determined. Differences between matings for fearfulness, body weight and egg production were not significant. However, in the case of egg production, both the mating × cage size and mating × cage tier interactions were significant. The genotype × environment interactions were interpreted to be due, in part, to varied behavioral response to the environment. Dominant birds had both a higher rate of egg production and heavier body weight than their subordinate cage mates. Birds housed in the larger cages (516 cm2 per bird) were less fearful than those in the smaller cages (412 cm2 per bird). Lower fearfulness was associated with higher egg production.
DIGESTIBILITY AND PROTEIN QUALITY EVALUATION OF RAPESEED FLOUR
Authors: BELL J. M. , GIOVANNETTI P. , SHARBY T. F. , JONES J. D.
Published: March 2010

Flour was prepared from Echo (B. campestris, low erucic acid) and Tower (B. napus, low erucic acid and low glucosinolate) cultivars of rapeseed by dehulling, myrosinase inactivation, washing in water, and hexane extraction. Over 97% of the original glucosinolates were removed. The flours contained over 60% protein. In protein quality tests with weanling rats, those fed rapeseed flour (cv. Echo) grew more slowly than the casein controls. Covariance analysis indicated that these differences could be associated with differences in feed intake or acceptability of the diet. Protein efficiency ratios were similar for rapeseed flour and casein (3.45 and 3.37, respectively). Tests with weanling mice involving rapeseed flour (cv. Echo) compared with soybean meal, in diets containing 8, 12 and 16% protein, revealed that rapeseed flour was superior to soybean meal as a protein source and had higher digestibility of protein and energy. In a similar test with Tower flour, protein quality ratings and digestibility coefficients again were superior to those for soybean meal. Rapeseed flour of either cultivar contains highly digestible protein (85–90%) and energy (88–91%). It contains protein equal to casein and superior to soybean protein in terms of PER and biological value. Both flours showed tendencies to be slightly less palatable than the control protein sources.
TRUE METABOLIZABLE ENERGY VALUES FOR POULTRY OF CANADIAN BARLEYS MEASURED BY BIOASSAY AND PREDICTED FROM PHYSICAL AND CHEMICAL DATA
Authors: SIBBALD I. R. , PRICE K.
Published: March 2010

Canadian barleys, having bulk densities ranging from 40.0 to 70.2 kg/hl, were assayed for true metabolizable energy (TME), gross energy, ether extract, crude fibre, protein, ash, calcium, phosphorus, starch and sugar. Regression analysis showed that from 76 to 84% of the variation in TME values was accounted for by published techniques for predicting metabolizable energy values from chemical composition data. The TME value of barley was correlated with bulk density (r = 0.912 at 29 df) and crude fibre (−0.904 at 30 df). There were also highly significant (P < 0.01) correlations between TME and starch (0.833), starch + sugar (0.838) and ash (−0.758). Earlier studies have not found close relationships between metabolizable energy and the aforementioned physical and chemical parameters. The probable explanation is that TME values are not affected by variations in feed intake associated with differences in palatability whereas the earlier energy measures were subject to this form of variation.
MASS SELECTION FOR POST-WEANING GROWTH IN SWINE. IV. SELECTION RESPONSE AND CONTROL POPULATION STABILITY
Authors: RAHNEFELD G. W. , GARNETT I.
Published: March 2010

Recurrent mass selection for post-weaning average daily gain was practiced for 11 generations in a population of Lacombe swine. Response to selection was assessed from predicted response, 0.241 ± 0.023 kg; observed response, 0.146 ± 0.018 kg; estimated heritability, 0.327 ± 0.031; and realized heritability, 0.198 ± 0.016. Observed response was estimated to be 0.61 of the predicted. Examination of additive genetic variance, selection differentials, drift variance, inbreeding and regression of post-weaning average daily gain on generation time indicated that the pedigreed Yorkshire control population served as an adequate control. Gene effects were not found to be dependent on the sex of the organism as assessed by the genetic correlation between sexes, covariance between half-sib family means and the relative magnitude of parent–offspring-based estimates of heritability.
MASS SELECTION FOR POST-WEANING GROWTH IN SWINE. V. CORRELATED RESPONSE OF REPRODUCTIVE TRAITS AND PRE-WEANING GROWTH
Authors: GARNETT I. , RAHNEFELD G. W.
Published: March 2010

Female reproductive performance and pre-weaning survival and growth were examined in a population of swine over 11 generations of selection for post-weaning average daily gain (ADG). Three separate breeding groups were used: (1) a Lacombe (L) line selected each generation for ADG, (2) a Yorkshire control (Y) line, and (3) a crossbred Lacombe × Yorkshire group (LY) generated each generation from the L and Y lines. Breeding group differences were evident for litter size, perinatal mortality, pre-weaning mortality, gestation length, birth weight, pre-weaning average daily gain (PreADG) and weaning weight. Selection did not affect number born, number born alive, number weaned or birth weight. When the values for the L line were expressed as a deviation from the control, pre-weaning mortality showed an increase. The increase appeared to be due to a decrease in the control rather than an increase in the L line. Gestation length showed a negative response to selection. As in the case of pre-weaning mortality, the response appeared to be a reflection of the instability of the control line. Genetic gains in PreADG of 0.004 kg/day/generation were realized in both the L line and LY group. Correspondingly, responses of 0.18 and 0.19 kg/generation were realized for weaning weight in the L line and LY group.
DIETARY CHLORIDE REQUIREMENTS OF TURKEY POULTS FED WHEAT-SOYBEAN-MEAL-BASED DIETS
Authors: GARDINER H. E.
Published: March 2010

not available
THE INFLUENCE OF SEX, WITHIN BREED-OF-SIRE GROUPS, UPON THE HISTOLOGICAL PROPERTIES OF BOVINE LONGISSIMUS DORSI MUSCLE DURING POSTMORTEM AGING
Authors: JEREMIAH L. E. , MARTIN A. H.
Published: March 2010

The longissimus dorsi (LD) muscles from 104 bovine carcasses (32 bulls, 36 heifers, and 36 steers) in three breed-of-sire groups (Charolais, Simmental and Chianina) were utilized to evaluate possible sex differences in histological properties of the LD muscle and the response of these properties to postmortem aging at 2 C. Significant (P <.05) sex differences in degree of LD fiber fragmentation were observed within all groups. In two (Simmental and Chianina) of the three groups, the LD muscle fibers of steer carcasses fragmented to the greatest extent; and in the other group (Charolais), the LD muscle fibers of bull carcasses fragmented to the lowest degree. Significant (P <.05) postrigor sex differences in LD sarcomere lengths and fiber diameters were observed within all groups. Sarcomere lengths were greatest for steers in all groups, and shortest for heifers in two (Charolais and Simmental) of the three groups. Steers generally had smaller LD fiber diameters than bulls or heifers, but such sex differences were small. Following prolonged aging, heifers or steers had greater (P <.05) incidences of wavy LD fibers than bulls in two (Simmental and Charolais, respectively) of the three groups. While the histological response of LD muscle properties tended to be similar for all sexes both within and across groups, inherent differences in their histological muscle properties may require carcasses of different sexes to be aged for different lengths of time to achieve similar histological properties in the final product.
THE EFFECTS OF TIME OF INSEMINATION ON FERTILITY IN BEEF HEIFERS SYNCHRONIZED WITH PROSTAGLANDIN F2α
Authors: MANNS J. G. , WENKOFF M. S. , ADAMS W. M. , RICHARDSON G.
Published: March 2010

Two injections of prostaglandin F2α (PGF2α) spaced 12 days apart were used to synchronize estrus in Hereford heifers. Animals were inseminated at 75 h (group 2), 80 h (group 3) or 85 h (group 4) after the second injection of PGF2α. Untreated control animals (group 1) were inseminated as detected in estrus over an observation period of approximately 35 days. Immediately before, and 24 h after each PGF2α injection, blood was collected for progesterone assay. Fertility expressed as calving rates was as follows: group 1, 33/77 (43%); group 2, 30/79 (38%); group 3, 29/79 (37%); group 4, 20/73 (27%). Fertility was depressed at 85 h vs. control (P < 0.05) in PGF2α-treated animals but there were no other significant differences. Progesterone assays showed that 65% of animals had progesterone-secreting corpora lutea at the first injection of PGF2α. There was no relationship between fertility and either serum progesterone concentration or the day of the cycle at the second injection of PGF2α.
ESTIMATES OF CREEP FEED REQUIREMENTS OF NURSING CALVES AND THE TOTAL ENERGY REQUIREMENTS OF BOTH COW AND CALF TO PRODUCE THE WEANED CALF
Authors: PARKINS J. J. , MORRIS C. A. , WILTON J. W.
Published: March 2010

Metabolizable energy and net energy systems were used to calculate creep feed requirements of nursing beef calves. These methods allow estimation of cumulative energy requirements for creep feed of growing calves for any combination of birth weight, rate of weight gain, energy concentration of the diet and level of milk production of the dam. Creep feed requirements estimated by these methods are in reasonable agreement with experimental findings. As examples, the methods were used to calculate creep feed energy requirements and total energy requirements of cows and calves in two situations: (a) combinations of three levels of milk production and three cow sizes where calf growth rate is proportional to cow weight and (b) combination of three levels of milk production and calf growth rates where growth rates are assumed independent of cow size. In the latter situation, the extra energy required for a unit change in output increased with increased liveweight gain, but decreased with increased milk production. Overall biological efficiencies to weaning were also compared (including the annual energy requirements of the cow and the calf in relation to the weight of calf produced at weaning). Generally, for straightbreeding, larger cows of low milk yield were estimated to be more biologically efficient to weaning than smaller cows of high milk yield. When large bulls are mated to smaller cows (giving crossbred calves) those cows with faster growing calves and lower milk yields are biologically more efficient. However, these findings may not coincide with findings for economic efficiency.
FEEDING VALUE FOR BEEF STEERS OF CORN SILAGE AS AFFECTED BY HARVEST DATES AND FROST
Authors: CALDER F. W. , LANGILLE J. E. , NICHOLSON J. W. G.
Published: March 2010

An experiment was conducted in 3 consecutive yr with corn grown each year on a field from which silage was made of corn harvested at different dates before and after freezing. Yields of green and dry weight were recorded at each harvest. Individual whole plants and plant parts were evaluated for dry matter (DM), total nitrogen, total available carbohydrates and in vitro digestibility of DM. Animal gains, feed consumption and carcass grades were determined by feeding the silages to yearling Hereford steers and DM digestibility determined with sheep. The total yield and contribution of the ear increased from the first to the second harvesting date. The in vivo digestibility of DM of the silages declined between the second and final harvests in all years as did animal gain in years 1 and 3. The in vitro digestibility appeared to underestimate the effect of frost on the in vivo digestibility of silage made with corn. When the silages were fed to steers, they consumed more dry matter per day from that harvested on the intermediate date than from either the early or late date. Higher carcass grades occurred when the steers were fed corn harvested at the intermediate dates. The results of these experiments show clearly that corn which has been heavily frozen will loose dry matter and feeding value if left standing in the field for a period of time; however, corn harvested soon after freezing is not as seriously affected.
EFFECTS OF CULTIVAR ON THE UTILIZATION OF GROUND RAPESEE IN DIETS FOR GROWING–FINISHING PIGS
Authors: CASTELL A. G.
Published: March 2010

Low erucic acid cultivars of Brassica campestris L. (Span and Torch) and B. napus L. (Midas and Tower) were used to examine the effects of cultivar on the performance of 132 crossbred pigs fed, from 23 kg to 89 kg liveweight, diets containing ground rapeseed. The oil percentages and levels of total glucosinolates (mg/g oil-free meal) were, respectively, 39.1 and 8.2 (Span), 40.2 and 7.8 (Torch), 44.7 and 12.0 (Midas), 43.2 and 3.4 (Tower). Growth rates on 17% crude protein diets containing 10% rapeseed in experiment 1 ranged from 637 g/day (Midas) to 797 g/day (Tower), a significant (P < 0.05) difference, although feed:gain ratios and carcass measurements did not differ significantly between the four dietary groups. Results from experiment 2, in which B. campestris cultivars were used as 0 and 10% of pelleted diets fed for two 45-min periods daily, indicated that rapeseed depressed daily feed intake and gain significantly (P < 0.01) but did not adversely affect carcass measurements. Increasing the dietary level of B. napus cultivars, from 0 to 15% in experiment 3, depressed daily feed intake and gain of pigs fed Midas (P < 0.05) or Tower (NS) diets. Feed:gain ratios and carcass data were similar to those of the control pigs. Although Midas-fed pigs exhibited poorer (P < 0.01) live performance, their carcasses had less backfat (P < 0.01) with higher Carcass Value Indices (P < 0.01) and Record of Performance Scores (P < 0.05) than those fed tower diets. Results from the three experiments suggested that inclusion of rapeseed influenced the performance of growing–finishing pigs by an effect upon both the energy content and glucosinolate level of the diet consumed.
RESPONSE OF CHICKS TO THE FEEDING OF DIFFERENT RAPESEED OILS AND RAPESEED OIL FRACTIONS
Authors: MARCH B. E.
Published: March 2010

Growth rates of chicks and efficiency of feed utilization were similar when the diet contained 4% of either rapeseed oil or corn oil in one experiment and when the diet contained 10% of either rapeseed oil or soybean oil in a second experiment. Gums from high or low erucic acid rapeseed at dietary levels of 4–5% resulted in growth rates and feed efficiency similar to those obtained with the oils. Acidulated soapstock and non-acidulated soapstock from high and low erucic acid rapeseed, fed in comparison with oils, gave favorable results for growth rate. The non-acidulated soapstocks, probably as a result of their 6% mineral content, reduced feed efficiency slightly. There was no mortality attributable to any of the oils or oil fractions.
INFLUENCE OF DIETARY FABA BEANS AND CASSAVA ON PERFORMANCE, ENERGY AND NITROGEN DIGESTIBILITY AND THYROID ACTIVITY OF GROWING PIGS
Authors: ONAGHISE G. T. U. , BOWLAND J. P.
Published: March 2010

Nutritional value of ground unprocessed faba beans (FB) was studied with 120 growing pigs from 4 wk of age to market weight of 84 kg. Fifteen diets were fed utilizing FB as a partial or total replacement for soybean meal (SBM) in a barley-based diet containing 0, 20 and 40% cassava during the first 9-wk starting phase. During this phase, average daily feed intake (ADF), average daily gain (ADG) and efficiency of feed conversion (EFC) were not significantly altered by partial replacement of SBM by FB (up to 21% of the diet). Supplementation of these diets with L-lysine and DL-methionine did not significantly improve performance. Total replacement of SBM by FB, even when supplemented with lysine and methionine produced significantly lower (P < 0.01) ADF, ADG and EFC although amino acid supplementation significantly improved these diets. Cassava inclusion at up to 40% of the diet did not significantly reduce ADF, ADG or EFC and had no significant effects on blood thyroxine or triiodothyronine levels. Digestibility of energy and nitrogen tended to be reduced as FB levels increased, but the lowered digestibilities could account for only a small proportion of reduced performance. During the finishing phase, partial or total replacement of SBM by FB had no significant effects on EFC. FB diets produced significantly (P < 0.01) lower ADF and ADG. The results suggest that FB supplemented with adequate lysine and methionine may be fed as partial replacement (up to 21% of the diet) for SBM to weanling pigs from 6 kg liveweight.
NIPPLE FEEDING OF SUPPLEMENTAL PROTEIN TO CALVES
Authors: ROBINSON P. H. , MOWAT D. N. , CHAPMAN H. W. , PARKINS J. J.
Published: March 2010

Forty-eight Holstein bull calves initially averaging 90 kg were used in a 2 × 2 factorial design to compare two levels and two methods of feeding supplemental protein. The basal ration, which was fed free choice, consisted of shelled corn, minerals, vitamins and urea and provided 10.5% CP on a DM basis. Supplemental protein as 50% CP soyaflour was fed at levels of 228 g (H) and 126 g (L) per day. The soyaflour was fed either with the basal ration (C) or twice per day (in equal amounts) from a nipple bottle (N) after being mixed with approximately 2 liters of lukewarm water. Calves were housed in individual pens with wire mesh floors and fed for 70 days. The soyaflour slurry was vigorously consumed by calves. No significant differences (P <.05) occurred in any of the performance parameters. However, a trend toward reduced weight gains and DM intake was observed among calves fed treatment LN. A nitrogen metabolism trial was conducted concurrently utilizing the same calves. Calves fed the high level of protein retained more (P <.05) nitrogen and excreted more (P <.05) urine urea nitrogen than calves fed the low level of protein. Increases in levels of plasma urea nitrogen following feeding were greater (P <.05) and occurred later (P <.05) in nipple-fed compared to conventionally fed calves. A subsequent trial was conducted with 10 calves to determine extent of closure of the reticular groove. Post-feeding levels of both blood glucose and rumen strontium indicated a high degree of groove closure with bottle feeding.
NUTRITIVE VALUE OF SEDGE AND KENTUCKY BLUEGRASS HAYS GROWN IN ALBERTA
Authors: HORTON G. M. J. , McELROY L. W.
Published: March 2010

The nutritive values of sedge and Kentucky bluegrass hays grown in a partially drained lake bottom in central Alberta were assessed in the laboratory and compared with those of brome–fescue hay and oat straw. The extent and rate of in vitro digestion for each forage with rumen fluid from cows fed either sedge, Kentucky bluegrass or brome–fescue were measured using a two-stage technique. The forages were analyzed for proximate components and minerals, and the rumen fluid for trichloroacetic acid-insoluble nitrogen (TCA-N) and volatile fatty acids (VFA). The effects of sulphur and phosphorus supplementation on the in vitro digestion of purified cellulose in the presence of aqueous extracts of sedge, Kentucky bluegrass and brome–fescue were also determined. In vitro dry matter and cellulose digestibilities were highest for brome–fescue and lowest for oat straw; DMD values for Kentucky bluegrass were consistently higher (P > 0.05) than for sedge. Phosphorus supplementation did not enhance cellulose digestion with brome–fescue extract, but with sedge and Kentucky bluegrass extracts, the responses were significant. Ruminal TCA-N and VFA concentrations were highest after feeding brome–fescue, followed by Kentucky bluegrass and then sedge. These studies indicated that the nutritive value of brome–fescue hay was highest, followed by Kentucky bluegrass and sedge hays, and then oat straw.