Influence of Nutritional Regime on Age at Puberty in Gilts

Cunningham, P. J.; Naber, Clyde H.; Zimmerman, David; Peo, E. R.

doi:10.2527/jas1974.39163x

Cited by 20 publications

(8 citation statements)

References 10 publications

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“…Of great relevance in this study is the negative quadratic relationship between age and lifetime growth rate to puberty. In contrast to this quadratic relationship, a linear and negative relationship has been reported previously (Reutzel and Sumption, 1968;Cunningham et al, 1974;Hutchens et al, 1981;Price et al, 1981;den Hartog and Noordewier, 1984;Mabry et al, 1985). The manner in which previous results were analyzed, added to the variability in experimental design, may have masked the existence of a quadratic relationship, in that the existence of a linear relationship may be limited to restricted-fed gilts.…”

Section: Discussionmentioning

confidence: 61%

Effects of pre- and postpubertal feeding on production traits at first and second estrus in gilts.

Beltranena

Aherne

Foxcroft

et al. 1991

Journal of Animal Science

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The effects of feeding level on body weight (BW), lifetime growth rate, backfat thickness (BF), fatness (BF/BW) and ovulation rate at first (puberty) and second estrus were examined in 145 gilts. From 47.2 kg until puberty, gilts were fed 2.0 kg/d (L) or had ad libitum access to feed (H). From puberty to second estrus, the feed allowance of one-half of the L gilts was increased to 2.8 kg/d. Flush-feeding only normalized ovulation rate (OR) to that observed in gilts with ad libitum access to feed. At puberty, a quadratic negative relationship between lifetime growth rate and age indicated that age at puberty was minimum at a growth rate of less than or equal to .60 kg/d. Thereafter, age at puberty became independent of, or possibly positively related to, lifetime growth rate. Gilts with higher lifetime growth rate also were heavier and fatter at puberty. It was concluded that puberty may have been attained when a certain BF or fatness was achieved, because growth rate of restricted-fed gilts and quickly growing gilts with ad libitum access to feed may have been associated with reduced fat deposition. Hence, maximizing growth rate in replacement gilts does not hasten the attainment of puberty. Growth rate may be manipulated by feed restriction, in order to attain a target BW at boar stimulation (approximately 90 kg), which would coincide with a minimum age (approximately 155 d) and BW at puberty (approximately 97 kg). Nutritional flushing during the first estrous cycle then could be used to normalize OR at mating at second estrus of gilts that were restricted-fed when prepubertal.

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Section: Discussionmentioning

confidence: 61%

Effects of pre- and postpubertal feeding on production traits at first and second estrus in gilts.

Beltranena

Aherne

Foxcroft

et al. 1991

Journal of Animal Science

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“…Thus, if fatness level influences sexual development in gilts, it has less effect than age. In fact, the relation between backfat thickness and age at puberty is reported to be low in gilts (Cunningham et al, 1974 ;Friend et al, 1981 ;Hutchens et al, 1981 ;Den Hartog and Noordewier, 1984).…”

mentioning

confidence: 99%

Effects of age and live weight on the sexual development of gilts and boars fed two planes of nutrition

Prunier¹,

Bonneau²,

Etienne³

1987

Reprod. Nutr. Dévelop.

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Summary. The Age had a significant influence on puberty attainment in gilts while live weight had nearly no effect. Percentages of cyclic gilts in the CTRL, SW and SA groups were 32, 79 and 20, respectively. Ovarian weight was mainly dependent on live weight in cyclic as well as in prepuberal gilts. In the latter animals, the weight and length of uterine horns and cervix were influenced by both age and live weight, whereas in cyclic gilts the only obvious effect was that of age on uterine horn weight. Season of birth (autumn vs spring) had no effect on the puberty attainment of gilts.Introduction.

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“…Therefore, it seems that one of the limiting factors in the attainment of puberty would be breed dependence on the development of medium-size follicles. This may explain why age at puberty could not be modified by the levels of nutrition (Self et al, 1955;Cunningham et al, 1974;Friend, 1977).…”

Section: Discussionmentioning

confidence: 99%

Follicular Development during the Prepuberal Period of Different Morphological Types of Ovaries in Hampshire and Yorkshire Gilts Fed Two Planes of Nutrition1

Dufour

Fahmy

Flipot

1985

Journal of Animal Science

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Changes in follicular development of the ovary at 105, 140 and 175 d of age were observed on 48 prepuberal Yorkshire and Hampshire gilts raised on two planes of nutrition. The follicles from the left ovary were counted and measured by histological techniques. Both the nonatretic and the atretic (more than four pyknotic bodies) antral follicles were classified into six categories according to size, and each category was expressed as percentage of the total number. The proportion of nonatretic follicles belonging to the first category (.19 to .36 mm in diameter) was higher in Hampshire than Yorkshire gilts at d 105 (65.4 vs 47.6%; P less than .05), but not at d 140 and 175. The proportion of atretic follicles to the total number observed was higher in Yorkshire at d 175 than at d 140 and 105 (38.6 vs 21.9 vs 11.6%, respectively; P less than .05), whereas in Hampshire, significant differences were observed only between d 140 and 105 (25.2 vs 3.9%, respectively). The low-plane regimen reduced the percentage of nonatretic follicles of the third (.63 to 1.12 mm) and fourth (1.13 to 2.00 mm) categories in Yorkshire gilts from 14.4 and 7.2% to 9.7 and 4.0%, respectively (P less than .05). According to grouping, size and number of antral follicles, three morphological types of ovaries could be distinguished: honey-comb, grape-like and an intermediate class. Reanalyzing the data accounting for types resulted in radical reduction in the residual variation, hence many significant differences between the two breeds could be identified. At 140 and 175 d of age, Hampshires with honey-comb- and grape-like ovaries had greater numbers of medium and large follicles than Yorkshires (P less than .001). It is concluded that the slower follicular development observed at 105 d of age in Hampshire, as compared with Yorkshire gilts, allows accumulation of greater numbers of antral follicles at 140 and 175 d for both morphological types of ovaries.

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Influence of Nutritional Regime on Age at Puberty in Gilts

Cited by 20 publications

References 10 publications

Effects of pre- and postpubertal feeding on production traits at first and second estrus in gilts.

Effects of pre- and postpubertal feeding on production traits at first and second estrus in gilts.

Effects of age and live weight on the sexual development of gilts and boars fed two planes of nutrition

Follicular Development during the Prepuberal Period of Different Morphological Types of Ovaries in Hampshire and Yorkshire Gilts Fed Two Planes of Nutrition1

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