Trace mineral interaction on reproductive performance of beef cattle under range conditions in Edwards and McCulloch Counties, Texas /
| Main Author: | |
|---|---|
| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1989.
|
| Subjects: | |
| Online Access: | Link to ProQuest copy Link to OAKTrust copy ProQuest, Abstract |
| Abstract: | In Exp. I the effects of mineral supplementation on reproductive performance of Brangus-type cows grazing native range was monitored by tissue (serum and liver) parameters, body condition score (BCS) and days to conception (DTC) in cows and adjusted weaning weight (AWW) in their calves. Forth-five animals were randomly divided into three pasture groups. Vows within pastures were assigned either as negative control (NC; 3 cows) or to one of three supplements (4 cows per supplement). Feed treatments were a sorghum grain-urea based supplement (21.5% crude protein) fed at 1000 g/head daily, feed control (FC); FC with additional 15 g P (P) and P + 64 mg Zn + 10 mg Cu + 20 mg Mn (TM). All animals had free access to salt Cows were individually supplemented using Calan feeding gates from 25 d prepartum until the end of the breeding season (75 d) and were palpated 55 d later for fetal age. Ten d prior to breeding season and at palpation, serum and liver samples were collected for analysis of the supplemented trace minerals. Treatments did not influence serum and liver minerals, whereas a pasture effect was observed for serum and liver Zn and Cu concentrations (P<.05). Body condition scores and AWW were not influenced by treatment. Average DTC were 42, 35, 29 and 22 d for NC, FC, P and TM, respectively (P<.05). These results indicate that DTC may be influenced by nutritional factors apart from those affect NVS. Possible, specific nutrient requirements (especially trace minerals) are at times of greater importance than body condition for satisfactory reproductive performance in the beef cow. Experiment II was conducted to determine the influence of supplemental minerals on forage digestion in the bovine. The effects of supplemental feed concentrates were monitored by in vivo dry matter disappearance (DMD) of three material differing in fiber characteristics (sudan hay, alfalfa, meal and cotton). Trace element content of IVDMD residue, ruminal fluid and digesta of rumen particulate matter was also evaluated. Four English cross steers with well established rumen cannulas were maintained on sudan hay and white salt ad libitum for 30 d, then assigned to treatment... |
|---|---|
| Item Description: | "Major subject: Nutrition." Typescript (photocopy). Vita. |
| Physical Description: | xii, 126 leaves ; 29 cm |
| Bibliography: | Includes bibliographical references. |