Effect of a prolonged-release formulation of N-methionyl bovine somatotropin (sometribove) on milk composition

• Published in: Journal of dairy science Vol. 75; no. 7; pp. 1775 - 1793
• Main Authors: Barbano, D.M. (Cornell University, Ithaca, NY), Lynch, J.M, Bauman, D.E, Hartnell, G.F, Hintz, R.L, Nemeth, M.A
• Format: Journal Article
• Language: English
• Published: Savoy, IL Am Dairy Sci Assoc 01.07.1992; American Dairy Science Association
• Subjects: Biological and medical sciences; COMPOSICION QUIMICA; COMPOSITION CHIMIQUE; CONTEO DE CELULAS; Food industries; Fundamental and applied biological sciences. Psychology; HORMONAS PITUITARIAS; HORMONE HYPOPHYSAIRE; LACTACION; LACTATION; LAIT; LECHE; METHODE D'APPLICATION; METODOS DE APLICACION; Milk and cheese industries. Ice creams; NUMERATION CELLULAIRE; PROTEINAS DE LA LECHE; PROTEINE DU LAIT; RENDEMENT LAITIER; RENDIMIENTO LECHERO; VACAS LECHERAS; VACHE LAITIERE; Ox; Cow; Proteins; Vertebrata; Mammalia; Casein; Proteolysis; Quality; Production; Chemical composition; Artiodactyla; Degradation product; Ungulata; Milk
• DOI: 10.3168/jds.S0022-0302(92)77937-5
• ISSN: 0022-0302

Forty Holstein cows received biweekly injections of prolonged-release formulation of bST, and 39 received biweekly injections of excipient, in a study to evaluate the effects of long-term bST administration on milk composition and component production. Injections began at 60 +/- 3 d postpartum. Administration of bST increased production of milk and of all measured components. Concentrations of lactose (4.85 and 4.81%), fat (3.76 and 3.67%), total solids (12.57 and 12.44%), SNF (8.83 and 8.75%), casein (2.56 and 2.53%), and true protein (3.13 and 3.08%) were similar in milks from cows receiving bST and excipient, respectively. Percentages of NPN (times 6.38) and total protein were greater in milk from bST-treated cows (.179% NPN and 3.32% total protein) compared with milk from cows injected with excipient (.172% NPN and 3.24% total protein). Use of bST did not change the relative percentages of alpha(S)-casein, beta-casein, kappa-casein, beta-lactoglobulin, alpha-lactalbumin, or casein proteolysis products. A cyclical pattern of milk production, component production, and composition within each 14-d injection interval was observed. This suggests that a diminishing amount of bST was delivered during the latter third of each injection interval. There were no effects of bST on milk composition that would be of any practical significance to dairy product manufacturers or consumers