Postpartum reproductive performance of mares fed varying levels of protein.
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1984.
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| Subjects: | |
| Online Access: | Link to ProQuest Copy Link to OAKTrust copy |
| Abstract: | Thirty mares were fed varying levels of protein during the last 90 days of gestation and the first 90 days of the subsequent lactation to determine the effect of protein intake on mare postpartum reproductive performance, nitrogen status, weight gain and foal growth. Mares were divided into 3 treatment groups during gestation and lactation. Crude protein consumption was 8.6% of dry matter (DM) consumption for treatments A and B during gestation and 11.5% of DM for treatment C. Crude protein consumption during lactation was 11.2% of DM consumption for treatment A and 14.4% of DM consumption for treatments B and C. Digestible energy (DE) consumption during gestation and lactation was 22 and 31 Mcal/day, respectively, across all 3 treatments. Mare weight gain during gestation was .10, .21 and .26 kg/day for treatments A, B and C, respectively. This average daily gain was lower than projected, based on NRC (1978) recommendations. However, the decrease in weight gain could not be attributed to a decrease in body fat content based on body condition scores which indicated an increase in body fat suggesting a compositional change in the mares where muscle protein was being replaced by adipose tissue. Nitrogen digested and nitrogen retention were higher in treatment C than values observed in either A or B. Additionally, urinary nitrogen was higher in treatment C than A or B which resulted in no increase in efficiency of utilization of nitrogen consumed or digested. Similar results were observed in lactation as well. Significantly more nitrogen was digested in treatments B and C than in A. Urinary nitrogen was higher at the higher intakes as well. Although weight gain of mares during gestation was impaired due to dietary treatment, fetal development was unaffected. Mean birth weights were 46.3, 47.2 and 46.3 kg for treatments A, B and C, respectively. No differences were observed for heartgirth circumference or height. Growth rate of foals were affected by treatment. Foals nursing mares on low protein (A) grew at a slower rate than foals from either treatment group B or C. Rate of gain was also slower from birth to 90 days of age. There was no difference in gestation length, days from foaling to first estrus, length of first estrus, days from foaling and first ovulation, days from first to second estrus, length of second estrus, days from first to second ovulation or overall conception rates. Overall fertility was not affected as evidenced by total conception rates of 100% for all treatments at 90 days into lactation. |
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| Item Description: | "Major subject: Nutrition." Typescript (photocopy). Vita. |
| Physical Description: | x, 112 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references (leaves 101-108). |