Browsing by Author "Shaver, Randy Duncan"
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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 Effect of feeding a reduced-starch diet with or without amylase addition on lactation performance in dairy cows(Elsevier Science, 2010-02) Shaver, Randy Duncan; Steinberg, Wilhelm; Ensink, Jeroen; Ferraretto, Luiz; Bertics, Sandra J.; Carrilho Lopes, J.; Akins, Matthew; Gençoğlu, Hıdır; Uludağ Üniversitesi/Veterinerlik Fakültesi/Hayvan Besleme ve Beslenme Hastalıkları Anabilim Dalı.; 15753357900The objective of this study was to determine lactation performance responses of high-producing dairy cows to a reduced-starch diet compared with a normal-starch diet and to the addition of exogenous amylase to the reduced-starch diet. Thirty-six multiparous Holstein cows (51 +/- 22 DIM and 643 +/- 49 kg of body weight at trial initiation) were randomly assigned to I of 3 treatments in a completely randomized design: a 3-wk covariate adjustment period during which the cows were fed the normal-starch diet, followed by a 12-wk treatment period during which the cows were fed their assigned treatment diets. The normal-starch TMR did not contain exogenous amylase (NS-). The reduced-starch diets, formulated by partially replacing corn grain with soy hulls, were fed without (RS-) and with (RS+) exogenous amylase added to the TMR. Starch and NDF concentrations averaged 27.1 and 30.6%, 21.8 and 36.6%, and 20.7 and 36.6% (dry matter basis) for the NS-, RS-, and RS+ diets, respectively. Dry matter intake for cows fed the RS- diet was 2.4 and 3.2 kg/d greater than for cows fed the NS- and RS+ diets, respectively. Intake of NDF ranged from 1.19 to 1.52% of body weight among the treatments, with the RS- diet being 28% greater than the NS- diet and 13% greater than the RS+ diet. Milk yield averaged 50.4 kg/d and was unaffected by treatment. Fat-corrected milk yield was 2.9 kg/d greater for cows fed the RS- diet than for cows fed the NS- diet. Body weight and body condition score measurements were unaffected by treatment. Fat, solids-, and energy-corrected milk feed conversions (kilograms/kilogram of DMI) were 12 to 13% greater for cows fed the RS+ diet than for cows fed the RS-diet. Dry matter and nutrient digestibilities were lowest for cows fed the NS- diet and greatest for cows fed the RS+ diet, and were greater for cows fed the RS+ diet than for cows fed the RS- diet, with the exception of starch digestibility, which was similar. Greater conversion of feed to milk for dairy cows fed reduced-starch diets that include exogenous amylase may offer potential for improving economic performance.Publication Effects of exogenous amylase in transition dairy cows fed low-starch diets: 2. total tract digestibility and blood urea nitrogen(Kafkas Univ, Veteriner Fakultesi Dergisi, 2019-09-01) Shaver, Randy Duncan; Gençoğlu, Hıdır; GENÇOĞLU, HIDIR; Kara, Cağdaş; KARA, ÇAĞDAŞ; Biricik, Hakan; BİRİCİK, HAKAN; Efil, Mukaddes Merve; Türkmen, İbrahim İsmet; TÜRKMEN, İBRAHİM İSMET; DENİZ, GÜLAY; Kovanlıkaya, Arda; Kıvanç, Recep Tolga; Yıldırım, Ramazan; Bursa Uludağ Üniversitesi/Veteriner Fakültesi; 0000-0001-7051-1349; 0000-0001-5077-5689; AAH-4311-2021; AAH-4032-2021; HJZ-4775-2023The objective of this trial was to determine the effect of exogenous amylase during the transition period on total tract digestibility, rumen pH and blood urea nitrogen in lactating dairy cows. The effect of exogenous dietary amylase supplementation on lactation diets with low starch concentration (19.5% of dry matter) and dry period diets with moderate starch concentration was evaluated (15.5% of dry matter). A total of 30 multiparus Holstein cows were randomly assigned to two groups with amylase (n=15) or control (n=15). Three cows from each group were randomly selected and ruminally cannulated for digestibility trials. The research was conducted starting at 21 d prepartum until 84 d postpartum. Digestibility of dry matter, organic matter, neutral detergent fiber, starch, and crude protein remained unaffected by treatment in postpartum. Average pre- and postpartum rumen pH concentrations were 6.25 and 6.15, respectively, and did not differ between treatments. Blood urea nitrogen (BUN) concentrations were lower in cows fed amylase supplemented diet compared to those fed diet without amylase in both pre- and postpartum periods (P<0.001). In conclusion, the dietary supplementation of amylase did may not affect the digestibility of nutrients, however, it may decrease the BUN concentration in pre- and postpartum period for cows fed amylase. Therefore, it may offer potential for improving nitrogen efficiency in dairy cows.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.