Clinical mastitis in cows treated with sometribove (recombinant bovine somatotropin) and its relationship to milk yield.

Effect of sometribove (methionyl bovine somatotropin) on mastitis in 15 full lactation trials (914 cows) in Europe and the US and 70 short-term studies (2697 cows) in eight countries was investigated. In full lactation studies, sometribove (500 mg/2 wk) was given for 252 d, commencing 60 d postpartum. Although herds varied considerably, incidence of clinical mastitis within a herd was similar for cows receiving control and sometribove treatments. Relative risk analyses indicated no treatment effect, and percentage of mastitis during treatment was similar for control and sometribove groups. A positive linear relationship existed between peak milk yield and mastitis incidence (percentage of cows contracting mastitis or cases per 100 cow days); sometribove treatment did not alter this relationship. Increases in mastitis related to milk yield increase from sometribove or related to genetic selection were similar. When expressed per unit of milk, mastitis incidence declined slightly as milk yield increased; this relationship was not altered by sometribove. No effect on clinical mastitis was observed in 70 commercial herds utilizing sometribove for 84 d. However, effects were significant for stage of lactation and milk yield. Overall, studies represented a wide range of research and commercial situations demonstrating that sometribove had no effect on incidence of clinical mastitis during the lactation of treatment. Furthermore, sometribove did not alter typical relationships between milk yield or herd factors and incidence of clinical mastitis.

Effects of a prolonged-release formulation of sometribove (n-methionyl bovine somatotropin) on Jersey cows.

Milk production, feed efficiency, health, and reproduction were evaluated in 46 Jersey cows that received either 500 mg of sometribove (n-methionyl bST) in a prolonged-release formulation or an equivalent volume of excipient bi-weekly beginning at 60 +/- 3 DIM. Cows were fed a TMR for ad libitum intake and were milked twice daily. Treatment with sometribove increased 3.5% FCM production 5.3 kg/d (31.4%) over controls. Milk composition was not changed, except that milk P content averaged 51 ppm higher in bST-treated cows. Net energy intake was 4.8 Mcal/d (22.9%) higher in the bST-treated cows than in the controls. General health of all cows was good throughout the study, but the cows treated with bST had more cases of mastitis than did the control cows. The bST treatment produced localized reactions at the site of injection in some cows, but these reactions did not affect milk production. Sometribove treatment had no effect on reproductive performance; 85% of the treated and 100% of the control cows calved successfully. Treatment with bST for a full lactation did not affect performance during the initial 60 d of the subsequent lactation.

Seafood processing wastes ensiled with straw: utilization and intake by sheep.

Ensiled mixtures of seafood processing wastes and wheat straw were evaluated. Thirty-six crossbred wethers (average BW = 34 kg) were fed 1) a basal diet (hay and concentrate) alone, or a 1:1 ratio (DM basis) of basal and 2) ensiled fish waste plus straw (70:30, wet basis), 3) ensiled fish waste and straw (51:49), 4) ensiled crab waste plus straw (60:40), 5) ensiled crab waste plus straw (40:60), or 6) ensiled wheat straw (50% moisture). Dry molasses (5%) was included in all ensiled mixtures, and glacial acetic acid (16% vol/wt) was added to the crab waste mixtures. Among diets containing ensiled fish waste, DM digestibility was greater (P less than .01) for the diet containing silate with 70% fish waste than the diet containing 51% fish waste. There was no difference (P greater than .05) in DM digestibility between the two crab waste silages. Apparent digestibility of CP was greater (P less than .01) for diets containing fish than for those containing crab waste. Nitrogen retention (g/d) was positive for sheep receiving all diets but not different among treatments. Apparent absorption of P (g/d) was greater (P less than .01) by sheep fed fish waste silage diets than by those fed crab waste silage diets. Among seafood silages, DMI was greater (P less than .01) for sheep consuming the 60:40 than for those consuming the 40:60 crab waste silage diet and less (P less than .01) for sheep fed the 70:30 than for those fed the 51:49 fish waste silage diet. Seafood processing wastes potentially are valuable to ensile with crop residues for use as ruminant feedstuffs.

Responses by lactating cows in commercial dairy herds to recombinant bovine somatotropin.

Cows (890) in 15 US herds were assigned randomly in equal numbers to control or bST injections (500 mg in a prolonged-release form every 14 d for 12 wk) within three stages of lactation (57 to 100, 101 to 140, and 141 to 189 d postpartum) and two parity groups (primiparous and multiparous). Yield and milk composition were monitored 1 d/wk for 16 wk including 2 wk pretreatment and 2 wk posttreatment. Increases in milk and FCM due to bST injections were less at 57 to 100 d than at 101 to 189 d postpartum (milk 3.6 vs. 5.5; FCM 3.9 vs. 6.1 kg/d per cow), and increases in milk and FCM were more for multiparous than for primiparous cows (milk 5.5 vs. 4.2; FCM 6.0 vs. 4.7 kg/d cow). Temporarily, concentration of milk fat increased and protein decreased; later, concentrations for control and injected cows were similar. Postinjection milk fat concentration decreased, but milk protein concentration increased temporarily. The net increase in milk (and FCM) varied significantly among herds from 2.9 to 7.6 kg/d per cow (mean, 4.9 kg). Responses in FCM were similar over a wide range of pretreatment yields. A great variety of feed ingredients were fed as total mixed rations, and nutrient concentrations varied greatly. The SCC were similar before, during, and after treatment, but increase in FCM of injected cows exhibited a negative correlation with pretreatment SCC. Changes in body condition score of sometribove-injected cows varied among herds (.25 to -.45) and averaged -.02 compared with .07 for controls. There was no pattern in incidence of mastitis during sometribove injections.