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How Does Nutrition Influence Reproduction of the Range
Cow?
"...reducing
protein or energy pre-partum had little effect
on dystocia rates, even though birth weights were
altered in some experiments." |
By Dr. John Paterson, Montana
State University. Adapted from "Ask John a Nutrition
Question" column in Beef Questions and Answers
Newsletter.
Bearden and Fuquay (1992) summarized the effects
of inadequate and excessive nutrients on reproductive
efficiency. This summary shows that excessive protein
and/or energy could have negative effects on reproduction.
Often, there are questions by livestock producers who
are concerned that excessive dietary nutrients during
the last trimester of pregnancy may negatively influence
calf birth weights and dystocia. Oklahoma workers summarized
the effects of providing either adequate (not excessive)
or inadequate amounts of dietary energy and protein
on calving difficulty, reproductive performance and
calf growth. The research was consistent in suggesting
that reducing protein or energy pre-partum had little
effect on dystocia rates, even though birth weights
were altered in some experiments. Of the nine trials
summarized, seven showed that increased energy intakes
during the last trimester of gestation did not increase
calving difficulty. Producers have commented that supplemental
crude protein increases calf birth weight. Of the five
studies reviewed, one study showed that excessive protein
increased calving difficulty while four other studies
did not show any effect on dystocia, birth weight, calf
survivability or weaning weight.
Examples of Inadequate or Excessive Dietary
Nutrient Intake on Reproduction in Beef Cattle (Bearden
and Fuquay, 1992)
| Nutrient Consumption |
Reproductive Consequence |
| Excessive Energy Intake |
Low conception, abortion, dystocia, retained placenta,
reduced
libido |
| Inadequate Energy Intake |
Delayed puberty, suppressed estrus and ovulation,
suppressed
libido and spermatozoa production |
| Excessive protein intake |
Low conception rate |
| Inadequate protein intake |
Suppressed estrus, low conception, fetal resorption,
premature
parturition, weak offspring |
| Vitamin A deficiency |
Impaired spermatogenesis, anestrus, low conception,
abortion,
weak offspring, retained placentae |
| Phosphorus deficiency |
Anestrus, irregular estrus |
| Selenium deficiency |
Retained placenta |
| Copper deficiency |
Depressed reproduction, impaired immune system,
impaired
ovarian function |
| Zinc deficiency |
Reduced spermatogenesis |
Beef:
Questions & Answers is a joint project between
MSU Extension and the Montana Beef Council. This column
informs producers about current consumer education,
promotion and research projects funded through the
$1 per head checkoff. For more information, contact
the Montana Beef Council at (406) 442-5111 or at beefcncl@mt.net
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