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The longevity of dairy goats and their milk yield potential is conditioned by the pre-pubertal growth. This phase is essential to manage for breeders because it determines the production costs and growth of their animals.

Puberty and mammary development

The breeding phase of kid goats until puberty corresponds to the acquisition of sexual maturity and mammary gland development which will influence the future milk production. In order to reduce production costs and labor time, farmers reduced the weaning weight. This weaning strategy may be followed by ad libitum feeding phase to fill in underdevelopment of animals. However, impacts on mammary development and milk production have never been described in goats.

Feeding and mammary gland development in ruminants

In heifers and sheep’s, ad libitum feeding strategy during the pre-pubertal phase has a negative effect on mammary development and milk production (Sejrsen et al., 1982. Johnsson and Hart, 1985). However other observations showed no effect of feeding (Lohakare et al., 2012). In addition, the nutritional value of the diet can positively influence mammary development (McFadden et al., 1990; Albino et al., 2015). Therefore post-weaning ad libitum feeding without negative effects on mammary development and milk production seems possible by controlling the duration and composition.

Objective of the thesis

The objective of this thesis is to evaluate the impact of early weaning with ad libitum feeding on the development of the mammary gland and the milk potential in the kid.

This work will take place in three steps:

• Checking that early weaning is possible without negative effects on the growth of the goat.
• Identifying the effects of ad libitum feeding on mammary development and milk yield and controlling the length and feeding levels of this kind of feeding.
• Setting a nutritional composition of the ideal diet (ratio Energy / Protein) to optimize ad libitum feeding phase.

Clémence Panzuti has been working on this subject of thesis since the 1st october 2015 for 3 years. She is supervised by Frédéric Dessauge in the lactation team.

Bibliography

• Albino, R. L., M. I. Marcondes, R. M. Akers, E. Detmann, B. C. Carvalho and T. E. Silva.2015. Mammary gland development of dairy heifers fed diets containing increasing levels of metabolisable protein: metabolisable energy. Journal of Dairy Research 82(1): 113-120.
• Johnsson, I. D. and I. C. Hart.1985. Pre-pubertal mammogenesis in the sheep .1. The effects of level of nutrition on growth and mammary development in female lambs. Animal Production 41(DEC): 323-332.
• Lohakare, J. D., K. H. Sudekum and A. K. Pattanaik.2012. Nutrition-induced Changes of Growth from Birth to First Calving and Its Impact on Mammary Development and First-lactation Milk Yield in Dairy Heifers: A Review. Asian-Australasian Journal of Animal Sciences 25(9): 1338-1350.
• McFadden, T. B., T. E. Daniel and R. M. Akers.1990. Effects of plane of nutrition, growth-hormone and unsaturated fat on mammary growth in prepubertal lambs. Journal of Animal Science 68(10): 3171-3179.
• Sejrsen, K., J. T. Huber, H. A. Tucker and R. M. Akers.1982. Influence of nutrition on mammary development in prepubertal and post-pubertal heifers. Journal of Dairy Science 65(5): 793-800.

Contact

Frédéric Dessauge frederic.dessauge[at]rennes.inra.fr (supervisor)
Clémence Panzuti clemence.panzuti[at]rennes.inra.fr (PhD. student)