Impact of selection for residual feed intake on breeding soundness and reproductive performance of bulls on pasture-based multisire mating.

There is concern in the beef industry that selecting bulls for feed efficiency based on residual feed intake (RFI) may have a negative impact on bull reproductive performance and fertility. Here we investigated the impact of selection of bulls for low RFI on breeding soundness evaluation (BSE), reproductive performance, and fertility of bulls under natural service in multisire mating groups on pasture. Of the 412 RFI-tested bulls available, 98 (23.8%) were culled for performance, type, temperament, or other reasons, and 88 (21.4%) were culled for failing BSE, for an overall cull rate of 45.1%. From among the 314 bulls subjected to BSE, 32 (10.2%), 20 (6.4%), and 36 (11.4%) were culled for poor feet and legs, scrotal circumference, and semen quality, respectively. The BSE traits were not different (P > 0.10) between bulls categorized as either inefficient (+RFI) or efficient (-RFI), but the proportion of bulls that failed to meet the 60% minimum sperm motility requirement tended (P = 0.07) to be greater in the -RFI group than in the +RFI group (10.2% vs. 4.4%, respectively). In a subpopulation of 115 bulls, individual progressive sperm motility was greater (P < 0.05) in +RFI (85%) than -RFI (80%) bulls. A multisire natural mating experiment was conducted during 2 consecutive breeding seasons (2006 to 2007 and 2007 to 2008) using 18 +RFI and 18 -RFI bulls. The overall calving rate (calves born/cows exposed) was 72.9%. Mean number of progeny per sire was significantly greater (P < 0.01) in -RFI bulls (18.3) than in +RFI bulls (11.8). Selection for feed efficiency based on RFI appears to have no detrimental impact on reproductive performance and fertility in beef bulls bred in multisire groups on pasture. However, the decreased sperm motility and the greater number of progeny per sire associated with -RFI status need further investigation.

Processing conditions affect nutrient digestibility of cold-pressed canola cake for grower pigs.

Cold-pressed canola cake is a coproduct of biodiesel production that contains more residual oil than expeller-pressed and solvent-extracted canola meal. Cold-pressed canola cake might be an attractive feedstuff for swine due to local availability from small plants. However, the nutritional quality and content of anti-nutritional factors of cold-pressed canola cake are poorly defined and vary with processing conditions. This experiment evaluated cold-pressed canola cake processed using 4 different conditions: a nonheated and heated barrel at slow and fast screw speed in a 2 × 2 factorial arrangement. Seven ileally cannulated barrows (26 kg of BW) were fed twice daily at 2.8 × maintenance diets containing either 44% of 1 of the 4 cold-pressed canola cake samples, expeller-pressed canola meal, canola seed, or an N-free diet in a 7 × 7 Latin square. The objectives were to measure the energy and AA digestibility and to calculate standardized ileal digestible (SID) AA and NE content. Each 9-d experimental period consisted of a 5-d diet adaptation, followed by 2-d feces and 2-d ileal digesta collections, and 7 observations per diet were obtained. Cold-pressed canola cake contained 41% CP, 16% ether extract, and 5 µmol of total glucosinolates/g (DM basis). Both apparent ileal digestibility (AID) and total tract energy digestibility of energy in cold-pressed canola cake was 36% greater (P < 0.05) in heated vs. nonheated conditions and 8% greater (P < 0.05) in fast vs. slow screw speed without interaction, indicating that heat enhanced energy digestibility. The AID of energy of cold-pressed canola cake was 13 and 118% greater (P < 0.01) than expeller-pressed canola meal and canola seed, respectively. Heat and speed interacted (P < 0.05) for SID of AA of test ingredients, but effects were not consistent among AA. The DE and calculated NE content of cold-pressed canola cake was 0.73 and 0.52 Mcal/kg greater (P=0.001; DM basis), respectively, than expeller-pressed canola meal and did not differ from canola seed. Cold-pressed canola cake averaged 4.17 Mcal of DE/kg, 2.84 Mcal of NE/kg, 0.87% SID Lys, 0.46% SID Met, and 0.79% SID Thr (DM basis). In conclusion, processing conditions greatly affected the digestible nutrient content of cold-pressed canola cake. Content of residual ether extract was an important determinant of the energy value of cold-press canola cake, whereas residual glucosinolates did not seem to hamper nutrient digestibility.

Protein and starch concentrates of air-classified field pea and zero-tannin faba bean for weaned pigs.

Air-classified pulse (non-oilseed legume) protein and starch may replace specialty protein and starch feedstuffs in diets for weaned pigs. In Exp. 1, three specialty protein sources (5% soy protein concentrate, 5% corn gluten meal, and 5% menhaden meal in the control diet) were replaced with 16% zero-tannin hulled or dehulled faba bean, or 17.5% field pea protein concentrate. In total, 192 group-housed pigs (2 gilts and 2 barrows per pen; BW = 7.5 +/- 1.4 kg) were fed wheat-based diets (3.60 Mcal/kg of DE and 3.3 g of standardized ileal digestible Lys/Mcal DE) over 28 d for 12 pen observations per each of 4 diets. Overall, protein source did not affect ADFI, ADG, or G:F. Apparent total tract digestibility (ATTD) of DM, GE, and P was greater (P < 0.05) for dehulled faba bean and field pea protein concentrate diets than the diet with 3 specialty protein sources. In Exp. 2, faba bean and field pea starch concentrates were compared with corn, wheat, tapioca, and potato starch as dietary energy sources. In total, 36 individually housed barrows (BW = 8.0 +/- 1.5 kg) were fed 1 of 6 diets for 15 d. Feces and urine were collected from d 8 to 14, and jugular blood was sampled after overnight fast and refeeding on d 15. Starch source did not affect N retention as a percentage of N intake. For d 0 to 14, ADFI of pigs fed field pea starch was greater (P < 0.05) than pigs fed corn, wheat, potato, and faba bean starch. Pigs fed tapioca, field pea, wheat, or corn starch grew faster (P < 0.05) than those fed faba bean or potato starch. For d 0 to 14, pigs fed corn or wheat starch had a 0.1 greater (P < 0.05) G:F than pigs fed faba bean, field pea, or potato starch. The ATTD of DM, GE, CP, and starch and the DE value of potato starch were much less (P < 0.05) than those of other starch diets. Postprandial plasma glucose was 4.9, 6.3, and 9 mmol/L greater (P < 0.05) for pigs fed tapioca than for pigs fed faba bean, wheat, and potato starch, respectively. However, postprandial plasma insulin tended to be 844 and 577 pmol/L greater (P < 0.10) for pigs fed faba bean and corn starch, respectively, than for pigs fed potato starch. The high insulin response of pigs fed faba starch could not be explained. In conclusion, air-classified pulse protein concentrates can replace specialty protein feedstuffs in diets for weaned pigs. Feeding air-classified pulse starch concentrates to starter pigs achieved a similar N retention as a percentage of N intake. The factors responsible for the reduced ADFI associated with feeding faba bean starch remain unclear.

The nutritional value of expeller-pressed canola meal for grower-finisher pigs.

Expeller-pressed (EP) canola meal contains more residual oil than solvent-extracted canola meal and might be an attractive feedstuff for swine, but it has been poorly characterized. In Exp. 1, six ileal-cannulated barrows (36 kg of BW) were fed at 3x maintenance either a 44% EP canola meal diet or a N-free diet in a crossover design to measure energy and AA digestibility and calculate standardized ileal digestible (SID) AA and NE content, with 6 observations per diet. Each period consisted of a 5-d diet adaptation and a 2-d feces and 3-d digesta collection. The EP canola meal contained (% of DM) 38.5% CP, 13.3% ether extract, 2.42% Lys, 1.54% Thr, 0.62% Met, and 23.2 micromol/g of glucosinolates. Apparent total tract energy digestibility was 75.0% and the DE and predicted NE content were 3.77 and 2.55 Mcal/kg (in DM), respectively. The SID AA content (% of DM) was 1.77% Lys, 1.04% Thr, and 0.52% Met. In Exp. 2, a total of 1,100 pigs (25 kg of BW) housed in 50 pens were fed 5 dietary regimens with 0, 7.5, 15, and 22.5% or decreasing amounts (22.5, 15, 7.5, and 0%, respectively) of EP canola meal over 4 phases to validate performance and carcass characteristics. Diets were formulated to contain equal NE:SID Lys for each growth phase (g/Mcal; 4.04, d 0 to 25; 3.63, d 26 to 50; 3.23, d 51 to 77; 2.83, d 78 to 90). At slaughter, carcass characteristics were measured for all pigs, and jowl fat was sampled for 2 pigs per pen. For d 51 to 90, the 22.5% EP canola meal regimen was reduced to 18% (22.5/18%) because of decreased ADFI in phases 1 and 2. Overall (d 0 to 90), increasing dietary EP canola meal linearly decreased (P < 0.001) ADG and ADFI and linearly increased (P < 0.01) G:F. For 0 and 22.5/18% EP canola meal, respectively, ADG was 978 and 931 g/d, ADFI was 2.77 and 2.58 kg/d, and G:F was 0.366 and 0.378. Increasing dietary EP canola meal did not alter the carcass backfat thickness, loin depth, or jowl fat fatty acid profile. Pigs fed 22.5/18% EP canola meal reached slaughter weight 3 d after (P < 0.05) pigs fed 0% EP canola meal. In summary, EP canola meal provided adequate energy and AA; however, ADG was reduced by 3 g/d per 1% of EP canola meal inclusion, likely because of increased dietary glucosinolates. Thus, the amount of EP canola meal included in swine diets should be targeted to an expected growth performance and carcass quality. Finally, diets formulated to contain an equal NE and SID AA content did not entirely eliminate the risks for reduced growth performance associated with inclusion of an alternative feedstuff.

Physical and sensory characterization and consumer preference of corn and barley-fed beef.

Steaks from corn-fed and barley-fed beef were characterized by a trained panel, which rated corn-fed beef higher (p<0.05) for tenderness attributes and overall flavor intensity. Canadian consumers preferred (p<0.01) cooked and raw steaks from barley-fed beef, while Mexican consumers showed no preference (p>0.05) for either type of finished beef. Japanese consumers showed a preference (p<0.05) for the appearance of raw barley-fed steaks but a preference for cooked corn-fed steaks (p<0.05). No differences (p>0.05) were observed for Warner-Bratzler shear, marbling scores, cooking losses or Hunter colorimeter values. There was a trend for higher concentrations (p<0.08) of the saturated fatty acids in the barley treatment, but no differences (p>0.10) in mono or polyunsaturated fatty acids.

Evaluating the conjugated linoleic acid and trans 18:1 isomers in milk fat of dairy cows fed increasing amounts of sunflower oil and a constant level of fish oil.

The objective was to evaluate different levels of sun-flower oil (SFO) in dairy rations to increase vaccenic (trans-11-18:1) and rumenic acids (cis-9,trans-11-18:2) in milk fat, and assess the content and composition of other trans-octadecenoic (trans-18:1) and conjugated linoleic acids (CLA) isomers. Eighty lactating Holstein cows were fed control diets for 4 wk and then placed on 4 diets for 38 d; milk fat was analyzed after 10 and 38 d. The treatments were: control, 1.5% SFO plus 0.5% fish oil (FO), 3% SFO plus 0.5% FO, and 4.5% SFO plus 0.5% FO. The forage-to-concentrate ratio was 50:50 and consisted of barley/alfalfa/hay silage and corn/barley grain concentrate. There were no differences in milk production. Supplementation of SFO/FO reduced milk fat compared with respective pretreatment periods, but milk protein and lactose levels were not affected. There was a linear decrease in all short- and medium-chain saturated fatty acids (SFA) in milk fat after 10 d (25.5, 24.1, 20.2, and 16.7%) and a corresponding linear increase in total trans-18:1 (5.2, 9.1, 14.1, and 21.3%) and total CLA (0.7, 1.9, 2.4, and 3.9%). The other FA in milk fat were not affected. Separation of trans-18:1 isomers was achieved by combination of gas chromatography (GC; 100-m highly polar capillary column) and prior separation of trans FA by silver ion-thin layer chromatography followed by GC. The CLA isomers were resolved by a combination of GC and silver ion-HPLC. The trans-11- and trans-10-18:1 isomers accounted for approximately 50% of the total trans-18:1 increase when SFO/FO diets were fed. On continued feeding to 38 d, trans-11-18:1 increased with 1.5% SFO/FO, stayed the same with 3%, and declined with 4.5% SFO/FO. Rumenic acid showed a similar pattern on continued feeding as trans-11-18:2; levels increased to 0.43, 1.5, 1.9, and 3.4% at 10 d and to 0.42, 2.15, 2.09, and 2.78% at 38 d. Rumenic acid was the major CLA isomer in all 4 diets: 66, 77, 78 and 85%. The CLA isomers trans-7,cis-9-, trans-9,cis-11-, trans-10,cis-12-, trans-11,trans-13-, and trans-9,trans-11-/trans-10,trans-12-18:2 also increased from 0.18 (control) to 0.52% (4.5% SFO/FO). Milk fat produced from 3% SFO/FO appeared most promising: trans-11-18:1 and cis-9,trans-11-18:2 increased 4.5-fold, total SFA reduced 18%, and moderate levels of trans-10-18:1 (3.2%), other trans-18:1 (6.6%) and CLA isomers (0.5%) were observed, and that composition remained unchanged to 38 d. The 4.5% SFO/FO diet produced higher levels of trans-11-18:1 and cis-9,trans-11-18:2, a 28% reduction in SFA, and similar levels of other trans-18:1 (9.2%) and CLA isomers (0.52%), but the higher levels of trans-11-18:1 and cis-9,trans-11-18:2 were not sustained. A stable milk fat quality was achieved by feeding moderate amounts of SFO (3% of DM) in the presence of 0.5% FO that had 4% vaccenic and 2% rumenic acids.

Test duration for growth, feed intake, and feed efficiency in beef cattle using the GrowSafe System.

This study was conducted to determine the optimum test duration and the effect of missing data on accuracy of measuring feed efficiency and its 4 related traits ADG, DMI, feed conversion ratio, and residual feed intake in beef cattle using data from 456 steers with 5,397 weekly averaged feed intakes and BW repeated measurements taken over 91 d. Data were collected using the GrowSafe System at the University of Alberta Kinsella Research Station. The changes and relative changes in phenotypic residual variances and correlations (Pearson and Spearman) among data from shortened test durations (7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, or 84 d) and a 91-d test were used to determine the optimum test duration for the 4 traits. The traits were fitted to a mixed model with repeated measures using SAS. Test durations for ADG, DMI, feed conversion ratio, and residual feed intake could be shortened to 63, 35, 42, and 63 d, respectively, without significantly reducing the accuracy of the tests when BW was measured weekly. The accuracy of the test was not compromised when up to 30% of the records were randomly removed after the first 35 d on test. These results have valuable and practical implications for performance and feed efficiency testing in beef cattle.

Nutrient profiles in retail cuts of bison meat.

The objectives were to determine the nutrient composition and variation in eight cuts of bison meat in bulls and heifers and identify nutrient relationships in the clod and sirloin by principal component analysis. The nutrients analyzed were: energy, protein, total fat, saturated fat, monounsaturated fat, polyunsaturated fat, transfat, cholesterol, vitamin A, Ca, Fe, Na and moisture. Differences were observed in fat components between cuts and bulls had higher (P<0.05) amounts of total, saturated, monounsaturated and polyunsaturated fat in the blade compared to the other cuts. The sirloins had less (P<0.05) cholesterol than all the other cuts in bulls and the clod in heifers. Fat varied more than protein and moisture in all cuts. Four principal components (PC) accounted for 63.9% of the total variation of the nutrient composition. Total, monounsaturated and saturated fats were in PC1 and cholesterol in PC2 showing that cholesterol is independent of other fats. If dietary alterations elicit changes in bison meat fatty acid profiles, it may be possible to reduce cholesterol independent of total, monounsaturated or saturated fat.

Effect of prebreeding maintenance diet on subsequent reproduction by artificial insemination in alpine and Saanen goats.

The objective of this study was to investigate the effect of 2 levels of prebreeding nutrition on reproduction in yearling does artificially inseminated (AI) by the intrauterine laparoscopic method. Forty-two does (Alpine = 22 and Saanen = 20) were randomly penned in groups of 7 and were fed 1 of 2 diets. The diets contained 3.2 Mcal DE/d (MAINT) or 3.5 Meal DE/d (HIGH), which was 10 and 20% higher than the National Research Council recommendations for maintenance requirements. The does were on the 2 feed treatments for 8 wk, after which the MAINT group was switched to the HIGH group diet. A week later, they were fitted with Veramix sponges to synchronize estrus. The sponges were removed from 22, 10 and 10 randomly picked does after 17, 22 and 23 d, respectively. All the does showed estrus within 48 h of removing the sponges. Previously frozen Alpine or Saanen semen (0.5 ml) was deposited into the uterus of does exhibiting standing estrus after anesthetizing them with zylazine and ketamine. Pure breeding was practiced. All the does lost weight prior to breeding. Seventeen does (41%) conceived and kidded by AI while the rest returned to estrus about 23 d later. A significant difference (P < 0.05) in the kidding percentage was observed between the 2 breeds (Alpine = 64% and Saanen = 16%), while the kidding percentage between the 2 diets did not differ (P > 0.05). Of the does that kidded, seven (41%) had singletons, eight (47%) had twins, one had triplets and one had quadruplets. Average litter size (kids/doe kidding) by AI was 1.76. Although the does lost weight prior to breeding, this did not affect their reproduction.

Alberta dairy farm survey response.

All dairy producers in the Canadian province of Alberta were mailed a questionnaire to determine current management practices and production. This survey was undertaken to develop and to plan extension programs based on current dairy producer needs. Of the producers contacted, 802 (57%) responded to the survey questionnaire. The results indicated that the mean herd size was 67 cows, and mean daily milk production was 21.9 kg/d per cow. More than 60% of the producers reported that the majority of their calf losses occurred at birth, and another 15.6% stated that losses occurred within the 1st wk. Less than one-third of the cooperators individually penned calves to prevent contact among calves prior to weaning. Approximately 31% of the cows in the herds surveyed required two or more breedings, partially because of inadequate estrus detection; only 50.3% of the respondents had daily scheduled detection times. The most frequent health concerns perceived by the producers were mastitis, foot problems, and silent estrus. Educational and extension programs should focus on specific areas, such as newborn calf management and reproductive management, to improve the efficiency and profitability of dairy production in Alberta.

The effects of spaying and anabolic implants on the average daily weight gain of heifers on pasture.

Two studies were carried out to determine the effects of spaying and implanting on the growth of heifers and compare Ralgro and Synovex-S for spayed heifers. In the first study, 121 crossbred heifers were randomly allocated to four groups: intact and no implant; intact and progesterone and estradiol benzoate (Synovex-S); spayed and no implant; and spayed and Synovex-S. The average daily gain (ADG) and body weight (BW) data were analyzed as a 2 x 2 factorial experiment with a pasture effect which was considered as a block. Based on ADG for days 0-120, the response to implanting was 17.6% for spayed heifers and 1.8% for intact heifers. In the second study, 31 spayed heifers implanted with zeranol (Ralgro) were compared with 30 spayed heifers implanted with Synovex-S. The data were analyzed as a one-way analysis of variance. The ADG for spayed heifers on Ralgro did not differ significantly (p>0.05) from those implanted with Synovex-S over a period of 92 days, suggesting that both implants produce similar growth responses.