V. Nayigihugu

Camelina meal and crude glycerin as feed supplements for developing replacement beef heifers.

Angus × Gelbvieh rotationally crossbred yearling heifers (n = 99, yr 1; n = 105, yr 2) were used in a 2-yr randomized complete block design experiment with repeated measures to determine the effect of feeding camelina biodiesel coproducts (meal and crude glycerin) on serum concentrations of triiodothyronine, thyroxine, insulin, β-hydroxybutyrate, and glucose, as well as on growth and reproductive performance. Heifers were assigned to 1 of 15 pens, and pens were assigned initially to receive 7.03 k·•heifer(-1)·d(-1) of bromegrass hay plus 0.95 kg·heifer(-1)·d(-1) of 1 of 3 supplements for 60 d before breeding: 1) control (50% ground corn and 50% soybean meal, as-fed basis); 2) mechanically extracted camelina meal; or 3) crude glycerin (50% soybean meal, 33% ground corn, 15% crude glycerin, 2% corn gluten meal; as-fed basis). Preprandial blood samples were collected via the jugular vein on d 0, 30, and 60 of the feeding period. A 2-injection PGF(2α) protocol (d 60 and 70 of the study) was used to synchronize estrus. Heifers were artificially inseminated 12 h after estrus was first detected. Heifers not detected in estrus within 66 h received a GnRH injection and were artificially inseminated. Dietary treatment × sampling period interactions were not detected (P = 0.17 to 0.87). Dietary treatment did not affect BW (P = 0.44 to 0.59) or serum concentrations of thyroxine (P = 0.96), β-hydroxybutyrate (P = 0.46), glucose (P = 0.59), or insulin (P = 0.44). Serum concentrations of triiodothyronine were greater (P = 0.05) in heifers fed camelina meal. Additionally, dietary treatment did not affect the percentage of heifers detected in estrus before timed AI (P = 0.83), first-service pregnancy rates of those heifers detected in estrus (P = 0.97), or overall first-service pregnancy rates (P = 0.58). Heifers fed camelina meal, however, had greater (P = 0.05) first-service pregnancy rates to timed AI than did heifers fed the control and crude glycerin supplements. The cost per pregnancy was similar for heifers fed the crude glycerin or the control supplement, whereas the cost per pregnancy was the least for heifers fed camelina meal. We conclude that camelina coproducts can replace conventional corn-soybean meal supplements in the diets of developing replacement beef heifers.

Plasma fatty acids and reproductive performance of lactating beef cows fed rumen-protected fat

ABSTRACT Two experiments were conducted to evaluate the effects of rumen-protected fat (RPF) supplementation after or during estrus synchronization on plasma fatty acid concentrations and reproductive performance of lactating beef cows. In Exp. 1, primiparous (n = 59; 495 ± 50 kg) and multiparous cows (n = 43; 552 ± 64 kg) were used in a randomized complete block design. On d -10, cows were stratified by BW and age to receive either a beet-pulp-based supplement fed at 1.8 kg/d per cow (control) or a beet-pulp-based supplement containing RPF at 1.4 kg/d per cow. Cows were estrus synchronized from d –10 to -3, with timed AI on d 0. On d 0, cows were transferred to bromegrass pastures and supplemented for 30 d. In Exp. 2, multiparous cows (n = 168; 525 ± 62 kg) were used in a randomized complete design and estrus synchronized similarly as in Exp. 1. However, cows were supplemented from d –10 to 10 after timed AI. In Exp. 1, plasma concentrations of 18:2n-6 tended to be greater (P = 0.07) for cows fed RPF than for control cows after 30 d. In Exp. 2, plasma concentrations of 18:2n-6 and total fatty acids were greater (P ≤ 0.002) for cows fed RPF after 20 d of supplementation. In Exp. 1 and 2, reproductive performance was similar (P ≥ 0.72) between treatments. Rumen-protected fat fed to lactating beef cows during and after estrus synchronization increased plasma fatty acid status; however, the increased fatty acid status was not sufficient to improve reproductive performance of lactating beef cows.

Growth and Reproductive Performance of Beef Heifers Fed Carnival or Forager Field Peas 1

Carnival or Forager field peas were evaluated as replacements for a cornsoybean meal supplement in the diets of peripubertal beef heifers. Beginning 60 d before estrous synchronization, 90 Angus × Gelbvieh rotationally crossed heifers (330 ± 1.0 kg initial BW) were stratified by BW and allotted to 1 of 3 dietary treatments in a randomized complete block design experiment (10 heifers/pen). Diets included limited access to bromegrass hay plus a 62.6% ground corn and 37.4% soybean meal (DM basis; control) supplement fed at 1.36 kg of DM/heifer per day, ground Carnival peas at 1.41 kg of DM/heifer per day, and 90.7% ground Forager peas and 9.3% soybean meal at 1.41 kg of DM/heifer per day. Data were analyzed using pen (3/treatment) as the experimental unit and means were compared using the contrasts control versus field peas and Carnival versus Forager peas. Heifers fed field peas tended (P = 0.08) to have greater ADG and G:F than heifers fed the control during the first 30 d. Growth performance was not affected (P = 0.18 to 0.19) by dietary supplement during the second 30 d, but over the course of the 60-d feeding period, heifers fed field peas had greater (P = 0.04) ADG and G:F than heifers fed the control supplement. Variety of field peas did not influence (P = 0.18 to 0.47) the growth performance of heifers throughout the experiment. Pregnancy rate to AI was 43.3% for all dietary treatments. Forager and Carnival peas can replace conventional corn-soybean meal supplements fed to peripubertal beef heifers for 60 d before estrous synchronization.

Potential of High-Sugar Corn as a Fall and Winter Forage Resource for Grazing Beef Cattle

Abstract Three grazing experiments were conducted to determine the potential of dryland, high sugar (Cargill HS 60A; Cargill, Minneapolis, MN) corn forage for fall and winter grazing. For Trials 1 and 2, two ruminally cannulated steers continuously grazing a 1-ha high-sugar corn pasture during fall and winter were used to collect masticate samples. Masticate N declined (P=0.03) from mid September to mid October, but was not affected (P=0.19) by sampling date in the winter. Masticate fiber steadily increased (P=0.04) from mid November to mid December. Rate of in vitro OM digestion (IVOMD) was least (P=0.04) by the study’s end in both trials; however, extent of IVOMD did not change (P=0.26) in the fall. For Trial 3, 34 pregnant beef cows were allowed to graze either windrowed or standing corn forage during the fall. Leaves and upper and lower stalks were separated from whole corn plant collected from each forage type for chemical and nutrient determination before and during the grazing period. Lower and upper stalks had less (P=0.009) fiber content and greater (P=0.002) in vitro DM digestibility than leaves. Although harvesting method did not affect (P=0.10 to 0.88) nutrient variables, cows grazing standing corn forage had greater (P=0.03) ADG than cows grazing windrowed corn forage. Despite a decline in nutritional quality of high-sugar corn forage as the grazing season progressed, high-sugar corn forage provided a sufficient nutritional base to support BW gain of pregnant beef cows. Grazing windrowed high-sugar corn forage would not be recommended because an undetermined quantity of forage was lost to a windstorm, which might have contributed to a lower ADG for cows grazing the windrowed corn forage.

Growth performance and carcass characteristics of lambs fed Carnival or Forager peas1

Twenty-four black-faced lambs (24 ± 0.4 kg initial BW) were used in a randomized complete block designed experiment to determine the effects of feeding 2 varieties of field peas on growth and carcass characteristics. Lambs were blocked by BW and assigned randomly to 1 of 3 pens per block. Isonitrogenous diets included a corn-soybean meal supplement (control) or Carnival or Forager field peas (33% of dietary DM) replacing corn and soybean meal. Periods included a growing (56% roughage, 44% concentrate), transition (36% roughage, 64% concentrate), and finishing phase (14% roughage, 86% concentrate). Lambs fed Forager peas tended to have greater (P = 0.06) ADG than did lambs fed Carnival peas, with lambs fed the control diet being intermediate during the growing phase. Lambs fed Forager peas had greater (P < 0.001) ADG during the transition phase. However, G:F did not differ (P = 0.31) among treatments. Diets did not affect (P = 0.33) DMI during the finishing phase, but ADG and G:F (P = 0.06 to 0.10) tended to be greater for lambs fed Carnival peas than for lambs fed Forager peas, with control lambs being intermediate. Lambs fed Forager peas had (P < 0.02) greater overall ADG and final BW, whereas lambs fed the Carnival and control diets had similar growth performance. Carcass characteristics (P = 0.19 to 0.86) did not differ among dietary treatments. Field peas fed to lambs at 33% of dietary DM can be a substitute for feeding corn and soybean meal. However, Forager peas may not be as economically feasible as Carnival peas.

Production and Quality of Forage and Economics of Grazing a Hay Meadow in the Spring

Abstract An experiment was conducted to determine the effects of spring grazing on forage DM production and nutritive value, as well as the economics of spring grazing a flood-irrigated hay meadow. Two vegetation types were present: predominantly ‘Garrison’ fcreeping foxtail (Alopecurus arundinanceus Poir) and a complex mixture with both introduced and native species. With use of cages, samples of ungrazed and grazed treatments were collected before and after grazing and also in August. Eighty-eight Angus × Gelbvieh rotationally-crossed heifers (average BW = 361.3 kg) were allowed to graze from May 27 to June 8 at 5.4 heifers/ha. A sampling date effect (P