Brown, C. G.

Cobb, C.

Kerby, Joel L.

Neuendorff, Don A.

Randel, R. D.

Strauch, T. A.

English

Texas A&amp;M Repository

    PUBLICATIONS 2002 EFFECTS OF THE FIBROLYTIC ENZYME CATTLE-ASETM ON GROWTH OFPREPUBERAL ROMOSINUANO CROSSBRED HEIFERST. A. Strauch, D. A. Neuendorff, C. G. Brown, C. Cobb, J. L. Kerby,R. D. Randel, and F. M. Rouquette, Jr.Background. Heifers that reach puberty at an earlier age are more likely to rebreed andmaintain a yearly calving interval than those that reach puberty at a later age. In general, heifersthat gain weight rapidly will attain puberty at an earlier age than contemporary heifers thatexperience lower rates of gain. Two major hormones that affect rate of gain are growth hormoneand insulin-like growth factor-I (lGF-I). When growth hormone binds to its receptor in the liver,it stimulates the production and secretion of IGF-I. Both growth hormone and IGF-I havebeneficial effects on development of bone, muscle, and fat, and increased circulatingconcentrations of IGF-I have been positively correlated with improved reproduction. Cattle-Ase™ is a fibrolytic enzyme preparation that is available in both liquid and dried forms. It haspreviously been shown to improve diet digestibility and increase milk production in dairy cows.It was our hypothesis that ingestion of Cattle-Ase™ would increase circulating concentrations ofIGF-I, and enhance growth and possibly puberty attainment. We initiated two experiments, oneon pasture and one in drylot, to ascertain the effects of Cattle-Ase™ on growth of prepuberalheifers.Research Findings. In trial I (TRI), Cattle-Ase™ was delivered in a commercialmolasses-urea lick tank (24% CP with 18% NPN, 3% fat) to 54 fall-born, prepuberal, crossbredheifers grazing coastal bermudagrass (CBG) for 84 d. Heifers were assigned to two replicatepastures according to breedtype, age, and body weight (BW): 1) pasture only (P), 2) P +molasses-urea lick (M), and 3) P + M + Cattle-Ase™ (MC). Cattle-Ase™ was added at aminimum rate of 30 gl19 Ibs to a maximum rate of 60 gill Ibs molasses. Average molassesconsumed was 2.53 Ibslhd/d; thus, average urea intake was -.46 Ibslhd/d. Weights and bodycondition scores (BCS) were recorded at initiation and 28-day intervals in TR I, with bloodsamples collected at initiation and weekly. Serum samples from TRI were assayed forconcentration of IGF-I by RIA. There was no treatment effect (P > .10) on BW, BCS, or serumconcentrations of IGF-I throughout TRl, nor was there an effect on ADG (P=,36) with ADG asfollows: 1.19, 1.43, 1.41 ± .13 Ibs/hdld for P, M, Me, respectively (Figure 1).In trial 2 (TR2), heifers from TR 1 were reassigned to two treatments: 1) Cattle-Ase(CSE) and 2) control (C). The MC heifers were assigned to CSE, M heifers assigned to C, and Pheifers were divided equally between treatments. Heifers had ad libitum access to CBG hay and97were group fed 2: 1 com:soybean meal (33% CP) at 1% BW, with Cattle-Ase™ provided to CSEheifers at 1.85 glhd/d for 126 d. Supplement was adjusted for changing BW each 28 d. Weightsand body condition scores were recorded at initiation and biweekly in TR2, with blood samplescollected at initiation and weekly. In TR2, Cattle-Ase™ increased ADG (P < .04). The CSEheifers gained .92 ± .07 Ibs/hd/d compared to C heifers that gained .75 ±.04 Ibs/hd/d (Figure 2).Application. The effects of Cattle-Ase™ ingestion may be dependent upon a variety offactors such as the carrier, the amount of non-protein nitrogen consumed, and/or the foragesource. These studies demonstrated that addition of Cattle-Ase™ to molasses-urea lick tanks didnot improve ADG of prepuberal heifers grazing coastal bermudagrass pastures; however, additionof Cattle-Ase™ to a dry supplement when heifers consumed coastal bermudagrass hay increasedADG. While not confirmed with these data, the increase in ADG when Cattle-Ase™ was fed indry form may lead to decreased age at puberty, which would improve reproductive performanceof prepuberal heifers.ADG Trial}Treatment1.61.4 P> .101.21~ 0.8 1.19~:S 0.60.40.20--1....1-----ADGTrial2P<.040.8~0.6 .75.M ~ ~~ 0.4 .CSE.MC0.20TreatmentFigure 1. Average daily gain of heifersDuring Trial 1.Figure 2. Average daily gain of heifersDuring Trial 2.98

Effects of the Fibrolytic Enzyme Cattle-ASE?äó on Growth of Prepuberal Romosinuano Crossbred Heifers

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Effects of the Fibrolytic Enzyme Cattle-ASE?äó on Growth of Prepuberal Romosinuano Crossbred Heifers

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Effects of the Fibrolytic Enzyme Cattle-ASE?äó on Growth of Prepuberal Romosinuano Crossbred Heifers

Abstract

Similar works

Full text

Available Versions

Texas A&amp;M Repository

Texas A&M Repository