فهرس المقالات re-implanting

• حرية الوصول المقاله
  • صفحة الملخص
  • نص كامل
  
  1 - Effects of Surgical Spaying on Heifer Feedlot Growth Performance and Dietary Energetics
  A. Plascencia V.M. González-Vizcarra Y.S. Valdés-García A. Barreras A. Estrada-Angulo J.D. Urías-Estrada R.A. Zinn
  Fifty crossbred heifer calves were used in randomized complete block design experiment (5 heifers/pen and 5 replications per treatment), to compare effects on surgical spaying (SPAY) versus non-spayed intact (INTC) on growth-performance and dietary energetic efficiency أکثر

  Fifty crossbred heifer calves were used in randomized complete block design experiment (5 heifers/pen and 5 replications per treatment), to compare effects on surgical spaying (SPAY) versus non-spayed intact (INTC) on growth-performance and dietary energetic efficiency during a 175-d growing finishing period. Upon initiation of the study heifers were implanted with a medium potency anabolic implant (200 mg testosterone propionate and 20 mg estradiol benzoate) and were reimplanted at day 75 (100 days previously to finishing experiment) with a high potency anabolic implant (140 mg trenbolone acetate and 14 mg estradiol. During first 35 days, spaying tended (P=0.08) to depress average daily gain (ADG, 9.9%) and dry matter intake (DMI, 7.5%). Differences in ADG were consistent with treatment effects on DMI, as observed DMI for both treatments were in good agreement with expected based on the net energy (NE) value of the diet. The cumulative ADG during the first 70 days and overall, were lower (7.0% and 4.6%, respectively; P≤0.04) for SPAY vs. INTC heifers. Due numerically greater DMI for INTC heifers, gain efficiency and observed vs. expected dietary NE were similar (P>0.27) across treatments. Surgical spaying retard has an appreciable long-term negative effect on daily weight gain of otherwise implanted feedlot heifers. تفاصيل المقالة