Browsing by Author "Ferraretto, Luiz F."
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Item Effect of feed restriction on reproductive and metabolic hormones in dairy cows(Elsevier, 2014-02) Ferraretto, Luiz F.; Hackbart, Katherine S.; Nascimento, Aníbal Ballarotti; Dalla Costa, F.; Bender, Robb W.; Guenther, Jerry N.; Shaver, Randy Duncan; Wiltbank, Milo Charles; Gençoğlu, Hıdır; Uludağ Üniversitesi/Veterinerlik Fakültesi/Zootekni ve Hayvan Besleme Bölümü.; 15753357900The objective of this trial was to evaluate the effects of feed restriction (FR) on serum glucose, nonesterified fatty acids, progesterone (P4), insulin, and milk production in dairy cows. Eight multiparous Holstein cows, 114 +/- 14 d pregnant and 685 +/- 39 kg of body weight, were randomly assigned to a replicated 4 x 4 Latin square design with 14-d periods. During the first 8 d of each period, cows in all treatments were fed for ad libitum feed intake. Beginning on d 9 of each period, cows received 1 of 4 treatments: ad libitum (AL), 25% feed restriction (25FR), 50% feed restriction (50FR), and 50% of TMR replaced with wheat straw (50ST). Daily feed allowance was divided into 3 equal portions allocated every 8 h with jugular blood samples collected immediately before each feeding through d 14. In addition, on d 12 of each period, blood samples were collected before and at 60, 120, 180, 240, 300, 360, 420, and 480 mm after morning feeding. The conventional total mixed ration and total mixed ration with straw averaged 15.1 and 10.8%, 32.1 and 50.5%, and 26.8 and 17.0% for concentrations of crude protein, neutral detergent fiber, and starch, respectively. Cows that were feed and energy restricted had reduced dry matter intake, net energy for lactation intake, circulating glucose concentrations, and milk production, but greater body weight and body condition score losses than AL cows. Circulating concentrations of insulin were lower for cows fed 50FR (8.27 p,mu IU/mL) and 50ST (6.24 mu IU/mL) compared with cows fed AL (16.65 mu IU/mL) and 25FR (11.16 p,mu IU/mL). Furthermore, the greatest plasma nonesterified fatty acids concentration was observed for 50ST (647.7 mu Eq/L), followed by 50FR (357.5 mu Eq/L), 25FR (225.3 mu Eq/L), and AL (156.3 mu Eq/L). In addition, serum P4 concentration was lower for cows fed AL than cows fed 50ST and 25FR. Thus, FR reduced circulating glucose and insulin but increased P4 concentration, changes that may be positive in reproductive management programs.Item Influence of a reduced-starch diet with or without exogenous amylase on lactation performance by dairy cows(Elsevier Science, 2011-03) Ferraretto, Luiz F.; Shaver, Randy Duncan; Espineira, M.; Bertics, Sandra J.; Gençoğlu, Hıdır; Uludağ Üniversitesi/Veterinerlik Fakültesi/Hayvan Besleme ve Beslenme Hastalıkları Anabilim Dalı.; 15753357900The objective of this trial was to determine lactation performance responses in high-producing dairy cows to a reduced-starch versus a normal-starch diet and to the addition of exogenous amylase to the reduced-starch diet. Forty-five multiparous Holstein cows, 68 +/- 29 d in milk and 696 +/- 62 kg of body weight (BW) at trial initiation, were randomly assigned to 1 of 3 treatments in a completely randomized design; a 2-wk covariate adjustment period with cows fed the normal-starch diet was followed by a 10-wk treatment period with cows fed their assigned treatment diets. The normal-starch total mixed ration did not contain exogenous amylase (NS-). The reduced-starch diets, formulated by partially replacing corn grain and soybean meal with whole cottonseed and wheat middlings, were fed without (RS-) and with (RS+) exogenous amylase addition to the total mixed ration. All diets contained 50% forage and 19.8% forage neutral detergent fiber (dry matter basis). Starch and neutral detergent fiber concentrations averaged 27.0 and 30.9%, 22.1 and 35.0%, and 21.2 and 35.3% (dry matter basis) for the NS-, RS-, and RS+ diets, respectively. Expressed as a percentage of BW, dry matter intake was greater for cows fed RS- than for cows fed NS- or RS+. Intake of neutral detergent fiber ranged from 1.09 to 1.30% of BW among the treatments, with that of RS- being 21% greater than that of NS-. Milk yield tended to be greater for cows fed NS- compared with the RS diets. Milk fat content and yield were unaffected by treatment. Milk protein content and yield were greater for cows fed NS- compared with the RS diets. Concentrations of milk urea nitrogen were greater for cows fed RS diets compared with the NS- diet. Body weight, BW change, and body condition score were unaffected by treatment. Feed conversion (kg of milk/kg of dry matter intake) was 10% greater on average for cows fed NS- than for cows fed the RS diets, and tended to be 6% greater for cows fed RS+ compared with RS-. Feeding a reduced-starch diet formulated by partially replacing corn grain and soybean meal with a wheat middlings and whole cottonseed mixture compared with a normal-starch diet without addition of exogenous amylase to either diet reduced milk and component-corrected feed conversions. Addition of exogenous amylase to a reduced-starch diet was of minimal benefit in this study.Item Lactation response to a ruminally-protected B-vitamin product (Vicomb P plus)(Elsevier Science, 2010-05) Ferraretto, Luiz F.; Akins, Matt; Shaver, Randy D.; Gençoğlu, Hıdır; Uludağ Üniversitesi/Veterinerlik Fakültesi/Zootekni ve Hayvan Besleme Bölümü.