Body condition during pregnancy and lactation and reproductive efficiency of mares

doi:10.1016/0093-691X(84)90383-2

Theriogenology

Volume 21, Issue 6, June 1984, Pages 897-909

https://doi.org/10.1016/0093-691X(84)90383-2 Get rights and content

Abstract

In Experiment I, 32 mares were equally allotted to the following treatments: mares fed to A) high body condition from 90 days prepartum to foaling and maintained in high body condition to 90 days postpartum, B) high body condition from 90 days prepartum to foaling and allowed to lose body condition to 90 days postpartum, C) lose body condition from 90 days prepartum to foaling and maintained in low body condition to 90 days postpartum, and D) lose body condition from 90 days prepartum to foaling and allowed to gain weight after foaling to attain a high level of body condition by 90 days postpartum. After three cycles, pregnancy rate at 30 days postovulation was lower (P<0.05) in C mares (50%) than in those in the other three groups (100%). Maintenance of pregnancy to 90 days was also reduced (P<0.05) in C mares (25%) when compared with A, D (both 100%) and B mares (88%). Foal growth to 90 days of age was similar in all treatments. In Experiment II, 927 mares were evaluated for body condition and monitored for reproductive performance. Pregnancy rate was lower (P<0.05) and number of cycles/conception was higher (P<0.05) for barren and maiden mares entering the breeding season in thin condition and for pregnant mares foaling in thin condition (condition score less than 5.0) when compared with mares with a higher level of condition. Also, onset of estrus and ovulation appeared to be delayed in barren and maiden mares entering the breeding season in thin condition. Breeding efficiency was enhanced in mares entering the breeding season or foaling at a condition of 5.0 or above. Initial excess stores of body fat enhanced fertility. There were no detrimental effects of excess body fat stored in late gestation.

References (21)

U. Kanto et al.
Effect of energy intake during pregnancy and lactation on body composition in rats
J. Nutr.
(1980)
L.E. Donaldson
Relationships between body condition, lactation and pregnancy in beef cattle
Australian Vet. J.
(1969)
D.R. Lamond
Sources of variation in reproduction performance in selected herds of beef cattle in northwestern Australia
Australian Vet. J.
(1969)
R.W. Whitman
Weight change, body condition and beef cow reproduction
T.G. Dunn et al.
Nutrition and the postpartum interval of the ewe, sow and cow
J. Anim. Sci.
(1980)
G.E. Polliott et al.
A note on the use of condition scoring in commercial sheep flocks
Anim. Prod.
(1976)
F.T. Day
Some observations on the causes of infertility in horse breeding
Vet. Rec.
(1939)
J.L. Voss et al.
Effects of a nutritional supplement on pregnancy rate in nonlactating mares
J. Am. Vet. Med. Assoc.
(1974)
D. Witherspoon
Nutritional and breeding management of problem mares
Modern Vet. Prac.
(1977)
NRC

There are more references available in the full text version of this article.

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^☆: Technical article 17363, Texas Agr. Exp. Sta.

^b: Horse Section, Dept. of Anim. Sci.

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Body condition during pregnancy and lactation and reproductive efficiency of mares☆

Abstract

J. Nutr.

Relationships between body condition, lactation and pregnancy in beef cattle

Australian Vet. J.

Sources of variation in reproduction performance in selected herds of beef cattle in northwestern Australia

Australian Vet. J.

Weight change, body condition and beef cow reproduction

Nutrition and the postpartum interval of the ewe, sow and cow

J. Anim. Sci.

A note on the use of condition scoring in commercial sheep flocks

Anim. Prod.

Some observations on the causes of infertility in horse breeding

Vet. Rec.

Effects of a nutritional supplement on pregnancy rate in nonlactating mares

J. Am. Vet. Med. Assoc.

Nutritional and breeding management of problem mares

Modern Vet. Prac.