Last update: August 15, 2011 11:26:09 AM E-mail Print


The effect of bovine somatotropin (bST) administration on production characteristics of lactating Angora does with kids.


J.J. Davis., T. Sahlu, R. Puchala, M.J. Herselman, S.P. Hart, T.H. Teh, E.N. Escobar and J.M. Fernandez. E (Kika) de la Garza

Institute for Goat Research, Langston University, Oklahoma.


Fourteen Angora does (35 ± 2 kg) each with a single kid and in the first month of lactation were used to determine the effect of bST on fiber growth, milk production and blood metabolites. The experiment consisted of a two-week pre-treatment period, five weeks of weekly subcutaneous administrations of a slow release bST (n=7; Animal Sciences Division, Monsanto Co.) (period 1) and a four week post-treatment period (period 2). The weekly dose of bST was calculated to release .1 mg bST kg-1 d-1. Kids were separated from the does daily for 5 h and their BW recorded before and after suckling to estimate milk production. Fiber growth was measured by shearing does at the start of the experiment and at the end of Periods 1 and 2. DMI (mean = 1.9 kgDM/d; P > .74) and BW of does (mean = 34.8 kg; P > .47) were not affected by bST. ADG of kids suckling bST -treated does was greater than that of kids of untreated does during Period 1 (184 vs 139 g/d; P < .04) but not during Period 2 (140 vs 136 g/d; P > .75). Treatment with bST did not affect milk production in Period 1 (mean = 236 mL/5 h; P > .35) or Period 2 (mean = 201 mL/5 h; P > .29) or milk composition. No difference was found in clean fleece production during Period 1 (mean = 18.1 g/d; P > .97) or Period 2 (mean = 18.1 g/d; P > .64) or in fiber diameter (mean = 39.8 μm and 38.9 μm in Periods 1 and 2, respectively P > .80). Injection of bST did not affect plasma concentrations of glucose (mean = 49.5 mg/dL; P > .99), urea N (mean = 19 mg/dL; P > .33), total protein (mean = 72.S g/d; P > .29) or nonesterified fatty acids (mean = 122 μEq/L; P > .14). This study suggests that kid ADG may be improved when their dams are treated with bST.



Anim. Sci. 72 (Suppl 1), 138