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Puberty Onset Influencing Factors - Anatomy & Physiology (view source)
Revision as of 14:44, 8 September 2008
, 14:44, 8 September 2008→Nutrition
== Nutrition ==
== Nutrition ==
* Massive influence on pubertal onset. The best example is in dairy cattle.
* A major goal in management is to achieve a successful, uncomplicated birth by 24 months of age.
* In order for this to occur, appropriate nutrition and adequate body size must be achieved.
* When fed a high plane of nutrition in order to gain 2.0 lbs/day for the first 12 months of life, heifers reach puberty at 6-8 months. If this diet is continued into the second year of life, it can result in over-conditioning which will lead to problems during parturition and subsequent lactation.
* A second level of nutrition allows heifers to reach the same target weight (1200 lbs at 3 months), but they grow at a uniform weight of 1.5 lbs/day for the entire 24 months. They reach puberty at 9-11 months.
* Heifers fed a restricted diet or low quality feed to gain 1.2 lbs/day mostly reach puberty by 12 months. However, they are too small for successful pregnancy and parturition.. Therefore, they will not calf until 2-3 years of age and are less productive in terms of milk yield.
* Thus, feeding a higher plane of nutrition causes animals to reach the desired weight and exhibit oestrus much faster. But, this is not more economical because milk production during the first and second lactations will be reduced due to incomplete mammary development.
== Photoperiod ==
== Photoperiod ==