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Mammogenesis and Induced Lactation With or Without Reserpine in Nulliparous Dairy Goats

A. A. K. Salama^*,,1, G. Caja^*, E. Albanell^*, S. Carné^*, R. Casals^* and X. Such^*

^* Grup de Recerca en Remugants, Departament de Ciència Animal i dels Aliments, Universitat Autònoma de Barcelona, Bellaterra, Spain
Sheep and Goat Research Department, Animal Production Research Institute, 12311 Dokki, Giza, Egypt

¹ Corresponding author: ahmed.salama{at}uab.es

Nulliparous goats were used to evaluate the effects of a standard protocol for inducing lactation with or without using a prolactin-releasing agent (reserpine). Estrus was synchronized and goats were submitted to daily s.c. injections of estradiol-17ß and progesterone (0.5 and 1.25 mg/kg of body weight, respectively) for 7 d. The goats were divided into 2 groups and injected i.m. with 1 mg/d of reserpine (n = 7) or the vehicle (n = 7) on d 12, 14, 16, 18, and 20. Lactation was initiated by i.m. injections of dexamethasone (10 mg/d) from d 18 to 20. Goats were machine milked once daily from d 21 to 120, at which time they were mated with herd sires. Milk was measured and sampled daily during wk 1 of lactation and weekly thereafter. Udder traits were measured in all goats at d –2 (before the induction treatment) and on d 35 and 100 (during lactation). Goats initiated lactation on d 21 (100%) and milk yield increased thereafter. The milk yield of control and reserpine-treated goats increased as lactation advanced, peaking at wk 10 of lactation, when reserpine-treated goats yielded 1,079 ± 89 mL/d of milk compared with 850 ± 96 mL/d for control goats. Yet milk yield at the peak was only 55% of the peak milk yield observed in contemporary primiparous goats. The composition of initial milk (d 21) was different from that expected for colostrum. Milk composition stabilized after d 3 of lactation. There were no differences among groups for milk fat, protein, casein, or whey protein, but milk from control goats contained greater nonprotein nitrogen than that from reserpine-treated goats (0.48 ± 0.02 vs. 0.41 ± 0.02%). Teat length increased from 24.7 ± 1.1 to 34.5 ± 2.4 mm in control goats during mammogenesis (d –2 to 35), but stabilized in reserpine goats (25.2 ± 2.2 mm). The distance between teats (11.5 ± 0.4 cm), and the volume (922 ± 63 mL) and depth (15.6 ± 0.60 cm) of the udder increased similarly in both groups during mammogenesis and lactation. After mating, 82% of herdmates became pregnant, whereas only 21% of the lactation-induced goats conceived (1 reserpine-treated and 2 control goats). In conclusion, lactation induction was effective in nulliparous goats, but neither milk yield nor the side effects on fertility seem to support its recommendation.

Key Words: lactation induction • prolactin • milk composition • dairy goat

This article has been cited by other articles:

				B. R. Andrade, A. A. K. Salama, G. Caja, V. Castillo, E. Albanell, and X. Such Response to Lactation Induction Differs by Season of Year and Breed of Dairy Ewes J Dairy Sci, June 1, 2008; 91(6): 2299 - 2306. [Abstract] [Full Text] [PDF]