Using alfalfa leaf meal as a supplement in late-gestation beef heifer and nursing beef calf diets.

Two experiments were conducted to investigate using alfalfa leaf meal (ALM; 22% CP, DM basis) in beef cattle diets. In Exp. 1, a total of 24 late-gestation Angus heifers (initial BW 470 +/- 9 kg) were blocked by BW, calving date, and BCS to 1 of 4 dietary treatments in a randomized complete block design. All heifers were offered a basal hay diet (7.4% CP and 67.6% NDF, DM basis). Treatments were arranged as a 2 x 2 factorial consisting of CP supplied at 100 or 112.5% of the recommended daily intake using either soybean meal (SBM) or ALM as the supplemental protein source. Treatments were fed for an average of 100 d before calving. Total DMI was unaffected by supplemental protein source, although heifers consumed more (P < 0.001) ALM supplement than SBM supplement at the expense of hay and corn. Feeding 112.5% of recommended CP to heifers increased precalving rate of BW gain (P = 0.004) and DM digestibility (P = 0.003). Protein source did not affect DM digestibility (P = 0.17). Neither supplemental protein source nor protein amount affected changes in BCS or calving traits. In Exp. 2, replicates of treatments were conducted over 2 consecutive years at 2 locations in northern Minnesota to determine the effects of including ALM in creep-fed supplements on nursing calf performance, supplement BW gain efficiency (GF; BW gain over control/supplement intake), and cow performance. Treatments were control (no supplement), ALM supplement (58% ALM, as-fed basis), or a wheat middling- and soybean hull-based supplement (MIDD). Milk intake (estimated by the weigh-suckle-weigh technique) was similar among treatments. Creep-fed calves had greater (P < 0.001) ADG than control calves, whereas calves offered MIDD tended to have greater ADG (P = 0.05) than those offered ALM (1.38 vs. 1.30 kg/d, respectively). Calves offered MIDD had greater (P < 0.001) creep feed DMI than those offered ALM (2.6 vs. 1.3 kg/d, respectively). A year x treatment interaction was noted for GF (P = 0.02). In yr 1, GF for calves offered ALM was greater (P = 0.006) than GF for calves offered MIDD, but in yr 2, there were no differences. Alfalfa leaf meal may substitute for SBM in beef heifer wintering diets and conventional creep feed ingredients. When included in creep feed diets, ALM can result in slightly less ADG and less DMI, but supplement conversion efficiency may be increased.

Fixed-time insemination in peripuberal, lightweight replacement beef heifers after estrus synchronization with PGF2alpha and GnRH.

Estrus synchronization contributes to optimizing the use of time, labor, and financial resources by shortening the calving season, in addition to increasing the uniformity of the calf crop. We determined whether acceptable pregnancy rates could be achieved after synchronization of ovulation and fixed-time artificial insemination (AI) in peripuberal replacement beef heifers using gonadotropin-releasing hormone (GnRH) and PGF2alpha. Crossbred heifers from two herds (MH, n=239; SS, n=330) were wintered at a single location. After a prebreeding examination revealed that 55 heifers had a reproductive tract score (RTS) of 1 (infantile reproductive tracts), they were culled and the remaining heifers were assigned randomly to one of three treatment groups: administration of 25mg PGF2alpha i.m. on Days -12 and 0 followed by estrus detection and insemination between 10 and 14 h after an observed estrus (Control; n=173); administration of 100 microg GnRH i.m. on Day -6, followed by 25 mg PGF2alpha i.m. on Day 0, then fixed-time AI and administration of 100 microg GnRH i.m. on Day +2 (GPG; n=172); and, treatment as for group GPG in addition to administration of 100 microg GnRH i.m. on Day -12 (GGPG; n=169). Bulls were introduced 10 days after AI for 60 days to breed heifers which did not conceive after AI (clean-up bulls). On Days -12, -6, and 0 transrectal ultrasonography was used to monitor ovarian structures in a subset of heifers (30 per treatment). At 30-35 days after AI, ultrasound was used to determine the presence of a viable fetus. Presence of a fetus and stage of pregnancy were determined via palpation per rectum 61-63 days after the conclusion of the breeding season. Heifers in the MH herd (309+/-1.9 kg) were heavier (P<0.001) than those in the SS herd (283+/-1.7 kg) at initiation of the breeding season. Synchronized pregnancy rates were greater (P<0.05) in GGPG (25.4%) and GPG (22.1%) than Control (12.7%) heifers. Pregnancy rates were 9, 21, 32, or 31% for heifers with RTS of 2, 3, 4, or 5, respectively. The average diameter of 22 follicles induced to ovulate in heifers treated with GnRH (GPG and GGPG treatments) was 14.2+/-0.8 mm (range=10.0-23.6 mm). In conclusion, a fixed-time ovulation synchronization program using GnRH and PGF2alpha improved pregnancy rates in peripuberal, lightweight replacement beef heifers.

Health and environmental implications of using composted household and yard waste bedding in a cattle feedlot.

A study was conducted to determine the safety and feasibility of using municipal solid waste compost (MSWC) as a bedding material for cattle feedlots. Two pens in an open-front pole barn were bedded with either corn stalks or MSWC in each of two feeding periods (blocks) with two pens (23 x 34 m) per block. Block 1 used 336 heifers (initial BW, 398 kg) during a 104-d period (summer), and Block 2 used 276 steers (initial BW, 412 kg) during a 92-d period (winter). Blood concentrations of regulated elements (Cd, Cu, Mo, Pb, Ni, and Zn), electrolytes, glucose, or liver and kidney enzymes were unaffected (P > .05) by use of either bedding material. Polychlorinated biphenyls in perirenal fat were not detectable (< .5 ppm) in cattle bedded with either material. At slaughter, kidney Cu and kidney and liver Pb concentrations were greater (P < .05) for cattle bedded with MSWC. Despite this, tissue concentrations of these elements were well within those considered normal for healthy cattle. Regulated element concentrations of feed did not differ (P > .05) between diets within period, and neither did DMI or DM digestibility; therefore, cattle bedded with MSWC were likely inhaling additional amounts of these elements and excreting them through feces. More MSWC than corn stalks was required to supply a dry bed per animal daily (P < .05). Soiled bedding (manure as-is) output was similar (P > .05) for both bedding materials. On a DM basis, more manure (P < .05) was removed from the pen bedded with MSWC in Block 2. Total manure N and P removed was similar for both bedding materials. Nitrogen and P concentrations in manure were lower (P < .05) during Block 2, but total manure N removed was greater (P < .05) during Block 2. Total manure P removed from the pens was not affected by season. Under the conditions of this study, MSWC seemed to be a safe and effective bedding material for cattle feedlots.