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1.
An Acad Bras Cienc ; 91(4): e20180509, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31644641

RESUMO

In order to evaluate iron chelate in diets for sows during gestation and lactation and its effects on iron supplementation for piglets, a total of 50 pregnant sows in the third parity order were distributed according to a randomized block design with two treatments: diet without iron chelate supplementation (n=20); diet supplemented with 0.15% of iron chelate (n=30). The litters of sows were distributed into five different treatments: sows without iron chelate supplementation and piglets receiving intramuscular iron-dextran; sows without iron chelate supplementation and piglets receiving oral iron supplementation; sows supplemented with iron chelate and piglets receiving intramuscular iron-dextran; sows supplemented with iron chelate and piglets receiving oral iron supplementation; sows supplemented with iron chelate and piglets without iron supplementation. No influence of dietary supplementation of iron chelate was verified on the productive parameters of the sows. For the piglets, iron-dextran supplementation promoted higher weaning weight in comparison to non-supplemented piglets, although not differing to those received oral iron supplementation. Thus, iron chelate supplementation did not improve the productive parameters of sows, but it increased iron excretion in the feces, thus requiring iron supplementation for the piglets after birth.


Assuntos
Ração Animal , Animais Lactentes/crescimento & desenvolvimento , Dieta/veterinária , Suplementos Nutricionais/análise , Quelantes de Ferro/administração & dosagem , Suínos/crescimento & desenvolvimento , Ganho de Peso/efeitos dos fármacos , Animais , Fezes/química , Feminino , Quelantes de Ferro/análise , Lactação , Gravidez
2.
An Acad Bras Cienc ; 91(4): e20180907, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31644644

RESUMO

A total number of 300 (225 ducks and 75 drakes) Sudani ducks, 28-wk-old were divided into five groups to investigate the effects of dietary L-carnitine (LC) supplementation on productive, hatching and physiological performance as well as nutrients digestibility coefficients. The results indicated that the productive performance and Semen quality parameters (ejaculate volume, sperms concentration and advanced motility) were significantly improved by LC supplementation (150-450 mg /kg diet) as compared to the control. Hatchability of fertile eggs (%) was significantly improved, while total embryonic mortality was significantly decreased by supplementing 300 and 450 mg LC/kg diet. Supplementing different dietary LC levels resulted in significantly high values of hemoglobin, red and white blood cells count and lymphocyte (L) cells percentage, while it decreased heterophils (H) cells and H/L ratio. Serum albumin, total cholesterol and AST enzyme values were significantly low in ducks fed diets supplemented with LC. Serum triglycerides were significantly the lowest by feeding 300 and 450 mg LC/kg diet. Nutrients digestibility coefficients were significantly improved in drakes fed diet supplemented with 450 mg LC/kg diet. Conclusively, dietary LC supplementation at 300 or 450 mg/kg for duck breeders in summer could improve productive, hatching and physiological performance and nutrients digestibility coefficients.


Assuntos
Ração Animal , Carnitina/administração & dosagem , Dieta/veterinária , Suplementos Nutricionais , Patos/crescimento & desenvolvimento , Fenômenos Fisiológicos da Nutrição Animal , Animais , Análise Química do Sangue/veterinária , Digestão/fisiologia , Patos/fisiologia , Feminino , Masculino , Estações do Ano , Análise do Sêmen
3.
J Agric Food Chem ; 67(38): 10756-10763, 2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31483626

RESUMO

AFEX treatment of crop residues can greatly increase their nutrient availability for ruminants. This study investigated the concentration of acetamide, an ammoniation byproduct, in AFEX-treated crop residues and in milk and meat from ruminants fed these residues. Acetamide concentrations in four AFEX-treated cereal crop residues were comparable and reproducible (4-7 mg/g dry matter). A transient acetamide peak in milk was detected following introduction of AFEX-treated residues to the diet, but an alternative regimen showed the peak can be effectively mitigated. Milk acetamide concentration following this transition was 6 and 10 ppm for cattle and buffalo, respectively, but also decreased over time for cattle while tending to decrease (p = 0.08) for buffalo. There was no difference in acetamide concentration in the meat of cattle consuming AFEX-treated residues for 160 days compared to controls. Further investigation is necessary to determine the metabolism of acetamide in ruminants and a maximum acceptable daily intake for humans.


Assuntos
Acetamidas/análise , Ração Animal/análise , Bovinos/metabolismo , Produtos Agrícolas/química , Resíduos de Drogas/análise , Contaminação de Alimentos/análise , Carne/análise , Leite/química , Acetamidas/metabolismo , Amônia/química , Animais , Búfalos , Dieta/veterinária , Digestão , Leite/metabolismo
4.
An Acad Bras Cienc ; 91(3): e20181194, 2019 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-31411260

RESUMO

The present study demonstrates 30 plant bugs species associated with 50 records of prey and six records of mycophagy for Brazil. The data were compiled from Schuh's Catalog, the literature, specimens deposited in entomology museums and exemplars from different regions of Brazil sent for identification. Some of the data from the literature used did not presented complete information. This study aims to increase the knowledge of the relationships among plant bugs, prey and fungi and emphasize those species with potential for biological control strategies and pest integrated management.


Assuntos
Dieta/veterinária , Fungos , Heterópteros , Comportamento Predatório , Animais , Artrópodes , Brasil , Plantas
5.
J Anim Sci ; 97(8): 3274-3285, 2019 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-31363781

RESUMO

Tryptophan (Trp) is an indispensable amino acid (AA) for dogs of all life stages; however, although Trp requirements for growing dogs are derived from 3 dose-response studies, there are no empirical data on Trp requirements for adult dogs at maintenance. The study objective was to determine Trp requirements of adult dogs of 3 different breeds using the indicator amino acid oxidation (IAAO) technique. Four spayed or neutered Miniature Dachshunds (5.28 ± 0.29 kg BW), 4 spayed Beagles (9.32 ± 0.41 kg BW), and 5 neutered Labrador Retrievers (30.51 ± 2.09 kg BW) were used. After a 14-d adaptation to a Trp-adequate basal diet (Trp = 0.482% dry matter), all dogs were fed a mildly Trp-deficient diet for 2 d (Trp = 0.092% dry matter) before being randomly allocated to receiving 1 of 7 concentrations of Trp supplementation (final Trp content in experimental diets was 0.092, 0.126, 0.148, 0.182, 0.216, 0.249, and 0.283% dry matter) and all dogs received all Trp treatments. After 2-d adaptation to the experimental diets, dogs underwent individual IAAO studies. Total feed was divided in 13 equal meals; at the sixth meal, dogs were fed a bolus of L-[1-13C]-Phenylalanine (Phe) (9.40 mg/kg BW), and thereafter, L-[1-13C]-Phe was supplied (2.4 mg/kg BW) with every meal. Total production of 13CO2 during isotopic steady state was determined by enrichment of 13CO2 in breath samples and total production of CO2 measured using indirect calorimetry. The maintenance requirement for Trp and the 95% confidence interval (CI) were determined using a 2-phase linear regression model. Mean Trp requirements were estimated at 0.154, 0.218, and 0.157% (dry-matter) for Dachshunds, Beagles, and Labradors, respectively. The upper 95% CI were 0.187, 0.269, and 0.204% (dry-matter) for Dachshunds, Beagles, and Labradors. In conclusion, estimated Trp requirements are higher for Beagles compared with Labradors or Dachshunds, and all estimated requirements are higher than those currently recommended by the NRC and AAFCO.


Assuntos
Aminoácidos/metabolismo , Cães/fisiologia , Necessidades Nutricionais , Triptofano/metabolismo , Aminoácidos Essenciais/metabolismo , Animais , Tamanho Corporal , Peso Corporal , Calorimetria Indireta/veterinária , Dieta/veterinária , Feminino , Masculino , Oxirredução , Fenilalanina/metabolismo , Distribuição Aleatória , Especificidade da Espécie
6.
Res Vet Sci ; 125: 360-369, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31376718

RESUMO

Alpha-tocopherol-selenium (ATS) and ascorbic acid (AA) are the potent antioxidants. The present study investigated whether supplementation of ATS and AA in periparturient sows has positive effects on amelioration of oxidative stress, serum immunoglobulin G (IgG), lipid profile and sows performance. For this, twenty-four pregnant multiparous sows (landrace×indigenous) were randomly distributed into four groups (6 sows per group) 20 days before expected date of farrowing as Control (basal diet); ATS (basal diet + ATS); AA (basal diet + AA) and ATS-AA (basal diet + ATS plus AA). The results of the study revealed that the concentrations of triglyceride and cholesterol significantly reduced from day -7 to day 7 of farrowing irrespective of supplementations to sows, but the leptin concentration significantly reduced on day 7 of farrowing in ATS-AA supplemented sows (p<0.05). Moreover, sows of supplemented groups experienced decreased oxidative stress and cortisol level than control sows. The serum IgG concentration was significantly increased on day 7 post-farrowing in ATS group but it was much earlier on day 2 of farrowing in ATS-AA group (p<0.001). Supplementing sows with ATS and/or AA did not influence significantly the birth weight, weaning weight and litter size at weaning (p>0.05). Although piglet survival rate was not affected significantly by supplementation, however, piglet mortality rate was lowest in ATS-AA than any other groups. It was concluded that supplementation of ATS and/or AA to sows during late gestating and early lactating period ameliorated oxidative stress, improved lipid profile and serum IgG level without influencing reproductive performance.


Assuntos
Ácido Ascórbico/metabolismo , Metabolismo dos Lipídeos , Estresse Oxidativo , Selênio/metabolismo , Sus scrofa/fisiologia , alfa-Tocoferol/metabolismo , Ração Animal/análise , Animais , Animais Recém-Nascidos/fisiologia , Ácido Ascórbico/administração & dosagem , Contagem de Células Sanguíneas/veterinária , Peso Corporal , Dieta/veterinária , Suplementos Nutricionais/análise , Feminino , Lactação , Leptina/metabolismo , Tamanho da Ninhada de Vivíparos , Longevidade , Gravidez , Selênio/administração & dosagem , alfa-Tocoferol/administração & dosagem
7.
Vet Parasitol ; 271: 14-21, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31303198

RESUMO

Foraging behavior by parasitized herbivores can be interpreted as a decision-making process where individuals are faced with trading-off the ingestion of nutrients with the ingestion of potentially medicinal -and toxic- plant secondary compounds. We determined how parasitized sheep prioritize selection of crude protein, energy and a medicinal plant secondary compound (quebracho tannins-QT). Foraging preferences were tested in 40 lambs before experiencing a parasitic infection (Phase 1), during an infection (Phase 2; 10,000 L3Haemonchus contortus per lamb) and after chemotherapy (Phase 3). Lambs were assigned to four groups (10 lambs/group) such that animals in Group 1 (Control) could choose between foods of high (HEP) or low (LEP) energy to protein ratios. The other groups received the same choice, but QT were added (4%) to HEP (Group 2), to LEP (Group 3) or to both foods (Group 4). All groups under a parasitic infection (Phase 2) increased their preference for HEP (from 0.44 to 0.66 ±â€¯0.042; P < 0.05) and intake of digestible energy (from 0.106 to 0.126 ±â€¯0.007 Mcal/kg BW; P < 0.05) relative to Phase 1, a pattern that remained during Phase 3. Only lambs receiving QT in HEP increased their intake of QT from Phase 1 to Phase 2 (P < 0.05). Fecal egg counts and blood parameters revealed a parasitic infection (P < 0.05) in Phase 2 that subsided in Phase 3, although no differences were detected among groups (P > 0.05). The importance of protein nutrition on parasitized animals has been highlighted before, but these results suggest that lambs prioritized the ingestion of energy-dense over protein-dense foods or medicinal condensed tannins when challenged by gastrointestinal parasitism. Consumption of medicinal tannins represented a side-effect of the preference manifested for energy-dense foods during testing.


Assuntos
Fenômenos Fisiológicos da Nutrição Animal , Dieta/veterinária , Ovinos/fisiologia , Ovinos/parasitologia , Animais , Comportamento Alimentar/fisiologia , Preferências Alimentares/fisiologia , Nutrientes/metabolismo , Doenças dos Ovinos/parasitologia , Taninos/metabolismo
8.
J Dairy Sci ; 102(9): 8431-8440, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31255262

RESUMO

The seasonality of grass-based, seasonal-calving dairy systems results in disproportionately higher labor demands during the spring, when cows are calving, than in the remaining seasons. This study aimed to (1) examine the relationship between labor efficiency and profitability; (2) investigate strategies to reduce the hours worked per day by the farmer, family, and farm staff in the spring by having certain tasks outsourced; and (3) quantify the economic implications of those strategies. Data from an existing labor efficiency study on Irish dairy farms were used in conjunction with economic performance data from the farms. Tasks that required the highest level of farm labor per day in the spring were identified and hypothetical strategies to reduce the farm hours worked per day were examined. A stochastic budgetary simulation model was then used to examine the economic implications of employing these strategies and the effects of their use in conjunction with a proportionate increase in cow numbers that would leave the hours worked per day unchanged. The strategies were to use contractors to perform calf rearing, machinery work, or milking. Contracting out milking resulted in the greatest reduction in hours worked per day (5.6 h/d) followed by calf rearing (2.7 h/d) and machinery work (2 h/d). Reducing the hours worked per day by removing those tasks had slight (i.e., <5%) negative effects on profitability; however, maintaining the farm hours worked per day while utilizing the same strategies and increasing herd sizes resulted in profitable options. The most profitable scenario was for farms to increase herd size while contracting out milking.


Assuntos
Bovinos/fisiologia , Indústria de Laticínios/economia , Indústria de Laticínios/métodos , Dieta/veterinária , Estações do Ano , Trabalho/estatística & dados numéricos , Animais , Fazendeiros/estatística & dados numéricos , Fazendas , Feminino , Renda , Irlanda , Leite/economia , Admissão e Escalonamento de Pessoal/economia , Poaceae , Gravidez , Trabalho/economia
9.
J Dairy Sci ; 102(9): 8513-8526, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31255268

RESUMO

Intensive milk feeding and butyrate supplementation in calves stimulate body growth and affect gastrointestinal development. The aim of the present study was to investigate the synergistic effects of ad libitum milk replacer (MR) feeding and butyrate supplementation of MR on rumen and small intestinal growth and on gene expression in the small intestine related to growth and energy metabolism at weaning. Male Holstein calves (n = 32) received colostrum from birth to d 3 of age and MR either ad libitum (Adl) or restrictively (Res; 6 L of MR/d; 12.5% solids) with (AdlB+, ResB+) or without (AdlB-, ResB-) 0.24% butyrate from d 4 until wk 8 of age. From wk 9 to 10, all calves were weaned and were fed 2 L/d until the end of the trial. Concentrate, hay, and water were freely available. At d 80, calves were slaughtered, volatile fatty acids were measured in rumen fluid, and rumen and small intestine samples were taken for histomorphometric measurements. The expression of mRNA associated with the local insulin-like growth factor (IGF) system and glucose metabolism as well as lactase and maltase activities were measured in the intestinal mucosa. The small intestine was 3 m longer in Adl than in Res. In the atrium ruminis, papilla width was greater in Res than in Adl. Villus circumference, cut surface, and height in the duodenum, proximal jejunum, and ileum were greater in Adl than in Res and in the proximal, mid, and distal jejunum and ileum were greater in calves treated with butyrate. Crypt depth in the duodenum and proximal jejunum was greater in Adl than in Res and in the ileum was smaller in calves treated with butyrate. The villus height:crypt depth ratio was greatest in AdlB+ calves. In the proximal and mid jejunum, IGF1 mRNA abundance was lower in calves treated with butyrate. In the proximal jejunum, INSR mRNA abundance was greater in Res than in Adl. The abundance of PCK2 mRNA was greater in Res than in Adl in the duodenum and was greatest in ResB- in the mid jejunum. Lactase activity tended to be greater in Res than in Adl and after butyrate treatment in the proximal jejunum. The results indicated an elevated growth of the small intestinal mucosa at weaning due to intensive milk feeding and butyrate supplementation, and the local IGF system was involved in intestinal growth regulation. Rumen development was not affected by butyrate supplementation of MR and was slightly delayed due to ad libitum MR feeding.


Assuntos
Butiratos/administração & dosagem , Bovinos/crescimento & desenvolvimento , Dieta/veterinária , Trato Gastrointestinal/crescimento & desenvolvimento , Substitutos do Leite/administração & dosagem , Rúmen/crescimento & desenvolvimento , Animais , Colostro , Suplementos Nutricionais , Ácidos Graxos Voláteis/análise , Feminino , Trato Gastrointestinal/química , Fator de Crescimento Insulin-Like I , Lactase/metabolismo , Masculino , Leite/metabolismo , Gravidez , RNA Mensageiro/análise , Proteínas Recombinantes , Rúmen/química , Somatomedinas/genética , Desmame
10.
J Dairy Sci ; 102(9): 8502-8512, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31279552

RESUMO

Diet is known to affect rumen growth and development. Calves fed an all-liquid diet have smaller and less developed rumens and a decreased ability to absorb volatile fatty acids (VFA) compared to calves fed both liquid and dry feed. However, it is unknown how rumens respond when challenged with a defined concentration of VFA. The objective of this study was to assess the effects of 2 different feeding programs on VFA absorption in preweaned calves. Neonatal Holstein bull calves were individually housed and randomly assigned to 1 of 2 diets. The diets were milk replacer only (MRO; n = 5) or milk replacer with starter (MRS; n = 6). Diets were isoenergetic (3.87 ± 0.06 Mcal of metabolizable energy per day) and isonitrogenous (0.17 ± 0.003 kg/d of apparent digestible protein). Milk replacer was 22% crude protein, 21.5% fat (dry matter basis). The textured calf starter was 21.5% crude protein (dry matter basis). Feed and ad libitum water intakes were recorded daily. Calves were exposed to a defined concentration of VFA buffer (acetate 143 mM, propionate 100 mM, butyrate 40.5 mM) 6 h before euthanasia on d 43 ± 1. Rumen fluid samples were obtained every 15 to 30 min for 6 h to measure the rate of VFA absorption. Rumen tissues were obtained from the ventral sac region and processed for morphological and immunohistochemical analyses of the VFA transporters monocarboxylate transporter 1 (MCT1) and 4 (MCT4). Body growth did not differ between diets, but empty reticulorumens were heavier in MRS than MRO calves (0.67 vs. 0.39 ± 0.04 kg) and MRS calves had larger papillae areas (0.76 vs. 15 ± 0.08 mm2). We observed no differences between diets in terms of the abundance of MCT1 and MCT4 per unit area. These results indicate that the extrapolated increase in total abundance of MCT1 or MCT4 in MRS calves was not due to increased transporter density per unit area. Modeled VFA absorption metrics (flux, mmol/h, or 6 h absorbed VFA in mmol) were not different across diets. These results demonstrate that the form of calfhood diet, whether solely MR or MR and starter, does not alter VFA absorption capacity when the rumen is exposed to a defined concentration of VFA at 6 wk of age.


Assuntos
Bovinos/metabolismo , Dieta/veterinária , Ácidos Graxos Voláteis/metabolismo , Rúmen/metabolismo , Ração Animal/análise , Animais , Bovinos/crescimento & desenvolvimento , Masculino , Substitutos do Leite , Rúmen/crescimento & desenvolvimento , Desmame
11.
J Dairy Sci ; 102(9): 8486-8501, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31279553

RESUMO

Preweaning diet is known to affect rumen tissue appearance at the gross level. The objectives of this experiment were to investigate effects of different preweaning diets on the growth and development of the rumen epithelium and on putative rumen epithelial stem and progenitor cell measurements at the gene and cell levels. Neonatal Holstein bull calves (n = 11) were individually housed and randomly assigned to 1 of 2 diets. The diets were milk replacer only (MRO; n = 5) or milk replacer with starter (MRS; n = 6). Diets were isoenergetic (3.87 ± 0.06 Mcal of metabolizable energy per day) and isonitrogenous (0.17 ± 0.003 kg/d of apparent digestible protein). Milk replacer was 22% crude protein, 21.5% fat (dry matter basis). The textured calf starter was 21.5% crude protein (dry matter basis). Water was available ad libitum and feed and water intake were recorded daily. Putative stem and progenitor cells were labeled by administering a thymidine analog (5-bromo-2'-deoxyuridine, BrdU; 5 mg/kg of body weight in sterile saline) for 5 consecutive days and allowed a 25-d washout period. Calves were killed at 43 ± 1 d after a 6 h exposure to a defined concentration of volatile fatty acids. We obtained rumen tissue from the ventral sac and used it for immunohistochemical analyses of BrdU (putative stem and progenitor cells) and Ki67 (cell proliferation), gene expression analysis, and morphological measurements via hematoxylin and eosin staining. Epithelial stem and progenitor cell gene markers of interest, analyzed by real-time quantitative PCR, were ß1-integrin, keratin-14, notch-1, tumor protein p63, and leucine-rich repeat-containing G protein-coupled receptor 5. Body growth did not differ by diet, but empty reticulorumens were heavier in MRS calves (MRS: 0.67 ± 0.04 kg; MRO: 0.39 ± 0.04 kg). The percentage of label-retaining BrdU basale cells was higher in MRO calves than in MRS calves (2.0 ± 0.3% vs. 0.3 ± 0.2%, respectively). We observed a higher percentage of basale cells undergoing proliferation in MRS calves than in MRO calves (18.4 ± 2.6% vs. 10.8 ± 2.8%, respectively). Rumen epithelial gene expression was not affected by diet, but the submucosa was thicker in MRO calves and the epithelium and corneum/keratin layers were thicker in MRS calves. Presumptive stem and progenitor cells in the rumen epithelium were identifiable by their ability to retain labeled DNA in the long term, changed proliferative status in response to diet, and likely contributed to observed treatment differences in rumen tissue thickness.


Assuntos
Bovinos/crescimento & desenvolvimento , Dieta/veterinária , Rúmen/crescimento & desenvolvimento , Animais , Bovinos/fisiologia , Proliferação de Células , Células Epiteliais/fisiologia , Masculino , Rúmen/citologia , Células-Tronco/fisiologia , Desmame
12.
J Dairy Sci ; 102(9): 8546-8558, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31301834

RESUMO

In the semi-arid highlands of central Mexico, triticale (× Triticosecale L.) is emerging as an alternative, less water-demanding forage crop than alfalfa for dairy cattle. Studies reported here were aimed at evaluating triticale hay (TH) relative to alfalfa hay (AH) for lactating cow performance, apparent digestibility, N partition, and ruminal degradation kinetics of dry matter (DM), crude protein (CP), and neutral detergent fiber (NDF). Study 1 was conducted on a privately owned farm. Four barns were used to conduct 4 replicated 3 × 3 Latin squares (1 barn = 1 square), where each barn included 3 pens (experimental units) receiving 1 of 3 dietary treatments. Each pen had 62 Holstein dairy cows. All diets included a forage-to-concentrate ratio of 42:58 (DM basis), which is typical for intensive dairy farms of the region. Dietary treatments were formulated to replace AH with TH on a CP basis, and included (DM basis) 15.1% AH and 0% TH, 9.0% AH and 7.4% TH, and 0% AH and 16.4% TH. Diets were iso-energetic (1.64 Mcal of net energy for lactation/kg of DM) and iso-nitrogenous (17.9% CP). Pen-level DM intake and milk production were from all cows in the pen, but pen-level milk composition, apparent digestibility, and N partitioning were from 8 cows (observational units) randomly selected in each pen. Orthogonal contrasts were used to determine linear and quadratic effects of increasing TH from 0 to 7.4, and 16.4% of dietary DM. Although DM intake was not affected, there was a tendency for CP intake to decline linearly and for NDF intake to increased linearly as TH replaced AH in the diet. Milk production declined linearly by 0.077 kg/d for each additional percentage unit of TH in the diet, which amounted to a 3.5% decline when TH replaced AH entirely. However, no effect was observed on energy-corrected milk production because of a compensatory linear effect of increasing milk fat concentration with the incorporation of TH in the diet. Total-tract NDF digestibility tended to increase linearly by 18.5%, but no differences were detected for urinary urea-N excretion and for N utilization estimated as milk N/(fecal N + urinary N + milk N). Study 2 was an in situ trial conducted to determine the degradation kinetics of AH and TH used in study 1. In spite of differences in degradation kinetics parameters for DM, CP, and NDF, only NDF effective ruminal degradation tended to be greater for TH than AH. Replacing AH with TH at the level typically found in intensive dairy farms of the semi-arid regions of Mexico had minimal effects on milk production and N utilization.


Assuntos
Bovinos/fisiologia , Lactação/fisiologia , Medicago sativa , Nitrogênio/metabolismo , Triticale , Ração Animal , Animais , Clima , Indústria de Laticínios/métodos , Dieta/veterinária , Fibras na Dieta/administração & dosagem , Digestão , Feminino , Medicago sativa/metabolismo , México , Leite/química , Zea mays/metabolismo
13.
J Dairy Sci ; 102(9): 8559-8570, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31301843

RESUMO

Because of its high yield and the ability of cows to graze it in situ, fodder beet (FB) has become a popular crop in grazing systems, particularly for nonlactating cows. Due to its high sugar content, however, the transition to FB must be managed carefully to avoid rumen acidosis and associated metabolic dysfunction. The initial consumption of FB reduces ruminal pH; however, it is unclear whether this affects liver metabolism and results in systemic inflammation, as has been reported during subacute ruminal acidosis from high-grain diets. We used a quantitative case study approach to undertake additional measurements on a project demonstrating the effects of FB on urinary nitrogen excretion. The objective of our component, therefore, was to determine whether the inclusion of high rates of FB in the diet of nonlactating cows changed indicators of hepatic metabolism relative to a standard diet for nonlactating grazing cows. During the nonlactating period, multiparous, pregnant Holstein-Friesian cows were randomly assigned (n = 15 per treatment) to either pasture (8 kg of DM/cow per day) with corn silage (4 kg of DM/cow per day; PA) or transitioning onto an FB diet (8 kg of DM/cow per day) with pasture silage (4 kg of DM/cow per day; BT) over 14 d. Blood was sampled and the liver was biopsied during the adaptation period and after 7 d of full diet allocation. The hepatic expression of genes involved in peroxisomal oxidation was increased in cows adapting to FB, whereas the expression of genes involved in mitochondrial oxidation was increased when cows were on their full allocation of FB. These results indicate changes to fatty acid metabolism with FB consumption. Expression of 2 genes involved in the unfolded protein response was greater during the adaptation period in cows consuming FB, potentially reflecting negative effects of transitioning onto the FB diet on hepatic metabolism. Interestingly, expression of genes involved in the methionine cycle was increased in the BT cows. We hypothesize that this is a result of FB betaine absorption, although it is unclear to what extent betaine escapes ruminal degradation. While on the full diet allocation, there were lower serum concentrations of markers of hepatic stress in BT cows and no difference in expression of genes involved in oxidative stress compared with pasture-fed cows. However, there was an increase in plasma haptoglobin concentrations, indicative of an acute inflammatory response in BT cows. From this case study, we conclude that the results indicate no negative effects of the FB diet on liver metabolism and, possibly, positive effects on hepatic function. It appears, therefore, that the transition of nonlactating cows onto an FB diet can be managed to minimize the negative effects of the high sugar intake. Further research on the amount of betaine that escapes ruminal degradation in cows consuming FB would be of value to better understand whether betaine reduces liver damage in dairy cows consuming FB.


Assuntos
Beta vulgaris , Bovinos/metabolismo , Dieta/veterinária , Fígado/metabolismo , Ração Animal/efeitos adversos , Animais , Antioxidantes/análise , Beta vulgaris/efeitos adversos , Beta vulgaris/metabolismo , Ácidos Graxos/metabolismo , Feminino , Expressão Gênica , Concentração de Íons de Hidrogênio , Lactação/fisiologia , Leite/química , Nitrogênio/urina , Gravidez , Rúmen/química , Zea mays
14.
J Dairy Sci ; 102(9): 8571-8585, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31301845

RESUMO

Grazed grass is the cheapest feed available for dairy cows in temperate regions; thus, to maximize profits, dairy farmers must optimize the use of this high-quality feed. Previous research has defined the benefits of including white clover (Trifolium repens L.) in grass swards for milk production, usually at reduced nitrogen usage and stocking rate. The aim of this study was to quantify the responses in milk production of dairy cows grazing tetraploid or diploid perennial ryegrass (Lolium perenne L.; PRG) sown with and without white clover but without reducing stocking rate or nitrogen usage. We compared 4 grazing treatments in this study: tetraploid PRG-only swards, diploid PRG-only swards, tetraploid with white clover swards, and diploid with white clover swards. Thirty cows were assigned to each treatment, and swards were rotationally grazed at a farm-level stocking rate of 2.75 cows/ha and a nitrogen fertilizer rate of 250 kg/ha annually. Sward white clover content was 23.6 and 22.6% for tetraploid with white clover swards and diploid with white clover swards, respectively. Milk production did not differ between the 2 ploidies during this 4-yr study, but cows grazing the PRG-white clover treatments had significantly greater milk yields (+596 kg/cow per year) and milk solid yields (+48 kg/cow per year) compared with cows grazing the PRG-only treatments. The PRG-white clover swards also produced 1,205 kg of DM/ha per year more herbage, which was available for conserving and buffer feeding in spring when these swards were less productive than PRG-only swards. Although white clover is generally combined with reduced nitrogen fertilizer use, this study provides evidence that including white clover in either tetraploid or diploid PRG swards, combined with high levels of nitrogen fertilizer, can effectively increase milk production per cow and per hectare.


Assuntos
Bovinos/fisiologia , Dieta/veterinária , Lactação/fisiologia , Lolium , Trifolium , Ração Animal/análise , Animais , Indústria de Laticínios/métodos , Feminino , Fertilizantes/análise , Leite , Nitrogênio/análise , Gravidez , Estações do Ano
15.
J Dairy Sci ; 102(9): 7980-7996, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31255271

RESUMO

The objective of this study was to investigate the effects of concentrations of forages and corn distillers dried grains with solubles (DDGS) on ruminal fermentation, ruminal kinetics, and total-tract digestibility of nutrients in lactating dairy cows. Four lactating Holstein cows with ruminal cannulas were assigned to a 4 × 4 Latin square in a 2 × 2 factorial arrangement of treatments. Diets were formulated to contain low forage [LF; 17% forage neutral detergent fiber (NDF)] or high forage (HF; 24.5% forage NDF) and DDGS at 0 or 18% (0DG or 18DG) of diet dry matter (DM). Intake of DM was not affected by the diets. Daily mean ruminal pH was affected by forage NDF × DDGS interactions, as the lowest ruminal pH was observed among cows fed LF18DG (6.02). Apparent total-tract digestibility for DM, organic matter, crude protein, NDF, acid detergent fiber, and starch was not affected by diets. Cows fed LF diets had a greater total volatile fatty acid concentration compared with cows fed HF (122 vs. 116 mM). Molar proportions of acetate were greater for HF compared with that of LF diets (62.6 vs. 57.5 mmol/100 mmol) and greater for 0DG diet compared with that of 18DG diets (61.3 vs. 58.7 mmol/100 mmol) diets. The molar proportion of propionate was affected by forage × DDGS interaction as the greatest propionate molar proportion was observed with cows fed LF18DG diet (27.7 mmol/100 mmol). Also, molar proportion of butyrate was affected by forage × DDGS interaction, as the greatest butyrate molar proportion was observed in cows fed HF18DG diet (13.5 mmol/100 mmol). Average fractional dilution rate for all diets was 11.9%/h and was not affected by diets. Fractional passage rate of the solid phase was greater for HF than for LF (4.40 vs. 3.76%/h). The ruminal retention time of solid phase was greater for LF compared with HF diets (27.3 vs. 23.3 h). Fractional passage rate of DDGS was affected by forage × DG interaction, as the highest fractional passage rate of DDGS was observed with cows fed HF18DG diet (7.72%/h). Our results demonstrated that concentrations of forage, DDGS, and their interaction influence ruminal degradation and kinetics of diets fed. Diets formulated at 17% forage NDF at 17% (DM basis) can decrease milk fat concentration compared with diets formulated at 25% forage NDF. Additionally, feeding DDGS at 18% DM basis to lactating dairy cows did not affect milk fat concentration or yield.


Assuntos
Ração Animal , Bovinos/metabolismo , Grão Comestível , Rúmen/metabolismo , Zea mays , Ração Animal/análise , Animais , Indústria de Laticínios , Dieta/veterinária , Fibras na Dieta/metabolismo , Ácidos Graxos Voláteis/metabolismo , Feminino , Fermentação , Trato Gastrointestinal/metabolismo , Cinética , Lactação , Leite/metabolismo , Distribuição Aleatória , Ruminação Digestiva , Amido/metabolismo
16.
J Dairy Sci ; 102(9): 8027-8039, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31279544

RESUMO

Two experiments were carried out to evaluate different dietary buffers and their influence on (1) rumen pH in dairy cows and (2) milk production in dairy cows. The supplements included were calcareous marine algae (CMA; Lithothamnion calcareum), with or without marine magnesium oxide (MM; precipitated magnesia derived from seawater), and sodium bicarbonate (SB). Dietary treatments in experiment 1 consisted of the control [32.9% starch and sugar, and 19.9% neutral detergent fiber from forage per kg of dry matter (DM)] including no dietary buffer (CON); the control plus 0.45% DM CMA (CMA); the control plus 0.45% DM CMA and 0.11% DM MM (CMA+MM); the control plus 0.9% DM SB (SB). Diets were formulated to a dry matter intake (DMI) of 18 kg per cow/d. Dietary treatments in experiment 2 also consisted of CON (28.3% starch and sugar, and 23% neutral detergent fiber from forage per kg of DM), CMA, CMA+MM, and SB and were formulated to achieve identical intakes of experimental ingredients (80 g of CMA, 80 g of CMA plus 20 g MM, and 160 g of SB per cow/d) with a DMI of 22.6 kg per cow/d. Experiment 1 used 4 rumen-cannulated dairy cows in a 4 × 4 Latin square design. Rumen pH was measured over five 2-h periods, following feeding, using rumen pH probes. In experiment 2, 52 multiparous and 4 primiparous cows (62.7 ± 3.4 d in milk) were assigned to 4 experimental treatments for 80 d. Both CMA treatments maintained a greater mean rumen pH than the CON during 4 of the 5 periods following feeding and the CON had a greater number of hours below rumen pH 5.5 compared with all other treatments. Dry matter intakes tended to be higher on the SB compared with CON. The CMA treatment increased the production of milk fat and protein yield (kg/d) compared with all other treatments. Both CMA and CMA+MM increased milk fat yield compared with CON but were similar to each other and SB. Protein yield was highest in the CMA treatment compared with CON, CMA+MM, and SB. All 3 buffer treatments increased milk fat concentration compared with CON but did not differ from each other. The SB treatment reduced milk protein concentration and milk production efficiency, energy-corrected milk per kilogram of DMI. Results indicate that the addition of CMA can benefit milk fat and protein production when included in diets based on typical feedstuffs of the northern European region. The use of CMA when compared with SB, in such diets, can increase milk protein production and milk production efficiency.


Assuntos
Ração Animal , Bovinos/metabolismo , Óxido de Magnésio/administração & dosagem , Rodófitas , Rúmen/metabolismo , Animais , Tampões (Química) , Indústria de Laticínios , Dieta/veterinária , Suplementos Nutricionais , Feminino , Concentração de Íons de Hidrogênio , Lactação , Óxido de Magnésio/farmacologia , Distribuição Aleatória , Bicarbonato de Sódio/administração & dosagem
17.
J Dairy Sci ; 102(9): 7997-8010, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31279545

RESUMO

The objective of this research was to identify potential short-term metabolic bottlenecks of propionate metabolism in the liver of dairy cows in the postpartum (PP) period and how such bottlenecks are affected by feeding status. Propionate, produced primarily from the fermentation of starch, decreases dry matter intake for cows in the postpartum period, likely by stimulating oxidation of acetyl-CoA in the liver. In this study, 8 dairy cows [2 blocks of 4 cows each, 6.63 ± 1.19 (mean ± SD) days PP; body condition score of 2.84 ± 0.39] were administered a pulse dose of either 1.5 mol/500 mL of propionic acid (PA) or 500 mL of water (control; CON) to the rumen either 1 h before or 2 h after feeding in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. Liver tissue was sampled at -1, 10 and 20 min relative to dosing, and blood was sampled at -30, -20, -10, -1, 5, 10, 15, 20, 25, 30, and 60 min relative to dosing. We hypothesized that rapid propionate absorption results in bottlenecks as enzymes become saturated and cofactors require regeneration. The PA treatment increased plasma propionate and insulin concentrations rapidly, with peaks reached by 5 min regardless of feeding status and cleared from the plasma within 30 min of dosing. The PA treatment decreased plasma nonesterified fatty acid concentration over 30 min compared with CON before but not after feeding. The PA treatment decreased plasma ß-hydroxybutyrate concentration and increased plasma lactate concentration compared with CON both before and after feeding. The PA treatment also increased hepatic pyruvate and lactate concentrations compared with CON. The PA treatment tended to increase hepatic isocitrate and fumarate concentrations but did not affect hepatic malate and oxaloacetate concentrations, suggesting that elevated mitochondrial NADH/NAD+ may have slowed the isocitrate dehydrogenase and fumarase reactions. The PA treatment also increased succinate concentration compared with CON, suggesting that a bottleneck may be present at succinate dehydrogenase. The PA treatment tended to increase citrate concentration despite having no effects on acetyl-CoA or oxaloacetate concentrations. These results are in agreement with our hypothesis that rapid absorption of propionate from the rumen and extraction by the liver results in metabolic bottlenecks in the liver that may affect feeding behavior and dry matter intake in dairy cows in the PP period.


Assuntos
Ração Animal , Bovinos/metabolismo , Fígado/metabolismo , Propionatos/metabolismo , Ração Animal/análise , Animais , Dieta/veterinária , Feminino , Lactação , Leite , Período Pós-Parto , Distribuição Aleatória , Rúmen/metabolismo
18.
J Dairy Sci ; 102(9): 8040-8058, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31279546

RESUMO

Kelp meal (KM) is a supplement made from the brown seaweed Ascophyllum nodosum, known to bioaccumulate iodine (I) and to be the richest source of phlorotannins, which can inhibit ruminal proteolysis and microbial growth. The objective of this study was to investigate the effects of KM on production, milk I, concentrations of blood metabolites, apparent total-tract digestibility of nutrients, and CH4 emissions in grazing dairy cows. Eight multiparous Jersey cows averaging (mean ± SD) 175 ± 60 d in milk and 12 primiparous Jersey cows averaging 142 ± 47 d in milk at the beginning of the study were assigned to either 0 g/d of KM (control diet, CTRL) or 113 g/d of KM (brown seaweed diet, BSW) in a randomized complete block design. Diets were formulated to yield a 70:30 forage-to-concentrate ratio and consisted of (dry matter basis): 48% cool-season perennial herbage and 52% partial TMR (pTMR). Each experimental period (n = 3) lasted 28 d, with data and sample collection taking place during the last 7 d of each period. Cows had approximately 16.5 h of access to pasture daily. Herbage dry matter intake increased, and total dry matter intake tended to increase in cows fed BSW versus the CTRL diet. Milk yield and concentrations and yields of milk components were not affected by diets. Similarly, blood concentrations of cortisol, glucose, fatty acids, and thyroxine did not change with feeding CTRL or BSW. However, a diet × period interaction was observed for milk I concentration; cows offered the BSW diet had greater milk I concentration during periods 1, 2, and 3, but the largest difference between BSW and CTRL was observed in period 2 (579 vs. 111 µg/L, respectively). Except for period 2, the concentration of milk I in cows fed KM did not exceed the 500 µg/L threshold recommended for human consumption. Diet × period interactions were also found for serum triiodothyronine concentration, total-tract digestibilities of crude protein and acid detergent fiber, CH4 production, and urinary excretion of purine derivatives. Overall, the lack of KM effects on milk yield and concentrations and yields of milk components indicate that dairy producers should consider costs before making KM supplementation decisions during the grazing season. Future research is needed to evaluate the concentration of I in retail organic milk because of the high prevalence of KM supplementation in northeastern and midwestern US organic dairies and possibly in other regions of the country.


Assuntos
Ração Animal , Ascophyllum , Bovinos/metabolismo , Suplementos Nutricionais , Iodo/metabolismo , Kelp , Leite/metabolismo , Ração Animal/análise , Animais , Indústria de Laticínios , Dieta/veterinária , Fibras na Dieta/metabolismo , Suplementos Nutricionais/análise , Digestão , Ácidos Graxos/metabolismo , Feminino , Lactação , Nutrientes , Distribuição Aleatória
19.
J Dairy Sci ; 102(9): 8011-8026, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31279550

RESUMO

Our objectives were to characterize responses in the field to a mix of fibrolytic enzymes using large commercial dairy herds and sufficient study power to evaluate milk production and reproductive responses to an enzyme treatment started during the precalving period. We hypothesized that the use of the enzyme treatment would increase milk production when provided to dairy cows precalving and for approximately 200 d of lactation. The study was conducted on 7,507 cows, in 8 replicates and 16 pens, at 3 dairies in the United States. Eight pens were randomly allocated as control pens and received no enzyme, and another 8 pens received enzyme treatment at a dose of 750 mL/t of dry matter feed. Milk production and energy-corrected milk yield were increased with the enzyme treatment by 0.70 and 0.80 kg/d, respectively, across a 5-month period. Milk fat percentage was not significantly increased by enzyme treatment, but milk fat yield was significantly increased by 0.040 kg/d, compared with controls. Milk protein yield increased 0.010 kg/d with enzyme treatment despite a small reduction of 0.020 percentage units in milk protein percentage. We found no evidence of an increase in the ln somatic cell count for the enzyme-treated cows. Body weight overall was not increased for enzyme-treated cows, but we did observe a numerical increase in dry matter intake (0.20 kg/head per day) for enzyme-treated cows. Most production responses to the enzyme treatment were influenced by dairy. Compared with controls, milk yield in enzyme-treated cows was significantly higher by 3.6 kg/d in dairy 2 and numerically higher by 0.60 and 0.20 kg/d in dairies 1 and 3, respectively. Reproduction, health, and risk of removal or death were not significantly influenced by treatment, apart from a reduced time to first breeding. Production responses to the enzyme treatment varied by dairy from substantial to minor increases, but variation among dairies was not evident in differences in dry matter intake or in partitioning of body weight among enzyme-treated and control pens and cows. It appears likely that the increase in production reflected increased digestibility of feed; however, further work is needed to identify factors influencing the variation in production responses to enzymes.


Assuntos
Ração Animal , Bovinos/fisiologia , Enzimas/administração & dosagem , Ração Animal/análise , Animais , Peso Corporal , Contagem de Células , Indústria de Laticínios , Dieta/veterinária , Digestão , Feminino , Lactação , Leite/química , Proteínas do Leite/análise , Distribuição Aleatória , Reprodução
20.
J Dairy Sci ; 102(9): 7970-7979, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31301837

RESUMO

This study was designed to evaluate the effects of substituting corn grain with nonforage fiber sources in diets containing soybean meal (SBM) or canola meal (CM) as the primary protein source. Sixteen Holstein cows were assigned to a replicated 4 × 4 Latin square design with 4 periods of 28 d each. Treatments were arranged as a 2 × 2 factorial with 2 protein sources (SBM and CM) and 2 dietary starch concentrations (21 and 27% dry matter, DM). Diets were formulated to contain 16.5% CP, and the 21% starch diets were obtained by replacing corn grain with soybean hulls and beet pulp. Protein source × starch interactions were observed for DM intake (DMI), milk fat and protein concentrations, milk protein yield, milk urea nitrogen, and feed efficiency. Cows fed CM diets had a higher DMI when dietary starch concentration was 27% compared with 21%, but those cows had DMI similar to that of cows on SBM diets regardless of the starch concentration. Milk fat percentage was decreased in cows fed CM with 27% starch compared with cows fed CM with 21% starch and cows fed SBM with 27% starch. Milk protein percentage and yield and milk lactose percentage were least in cows fed CM with 21% starch compared with the other 3 diets, but feed efficiency was greater for cows fed CM with 21% starch. Milk urea nitrogen was least in cows fed CM with 27% starch compared with the other 3 diets. Cows fed diets with 27% starch produced 2.5 kg/d more milk and 1.9 kg/d more energy-corrected milk compared with cows fed 21% starch. Digestibility of DM and organic matter was higher in cows fed SBM diets than in cows on CM diets, and cows fed 27% starch showed greater DM and organic matter digestibility than cows on 21% starch. Digestibility of neutral detergent fiber and acid detergent fiber was greater in diets with SBM than in those with CM. Molar proportion of acetate was the lowest for cows fed CM with 21% starch compared with cows fed SBM with 21% starch, with the remaining cows fed being intermediate and similar. However, propionate was highest for cows fed CM with 21% starch than for cows fed SBM with 21% starch, but the remaining treatments were intermediate and similar. Isobutyrate was greater for cows fed CM with 21% starch, which resulted in the lowest acetate:propionate ratio compared with cows fed the remaining treatments. Overall, we confirmed that the interaction of protein with starch in CM diets can sustain similar cow performance as with the SBM diets. Those making decisions about starch concentration and protein source should consider feed price when SBM or CM and different starch levels are being formulated in diets for lactating dairy cows.


Assuntos
Ração Animal , Brassica napus , Bovinos/fisiologia , Proteínas na Dieta/administração & dosagem , Soja , Amido , Ração Animal/análise , Animais , Indústria de Laticínios , Dieta/veterinária , Fibras na Dieta , Feminino , Lactação , Lactose/metabolismo , Leite , Proteínas do Leite , Distribuição Aleatória , Silagem/análise , Amido/análise , Zea mays/metabolismo
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