Milk Fat Depression in Dairy Cows: Role of Particle Size of Alfalfa Hay

Grant, Rick; Colenbrander, V.F.; Mertens, D.R.

doi:10.3168/jds.s0022-0302(90)78862-5

Cited by 79 publications

(49 citation statements)

References 17 publications

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“…However, Krause and Combs (2002) found that decreasing forage particle size tended to increase milk production despite the decrease in DMI. Grant et al (1990) and Teimouri Yansari et al (2004) reported that milk fat (g/kg) decreased with decreasing particle size due to the decrease of rumination time and rumen pH. Milk fat percentage is commonly used as an indicator of effective fibre, as it is often a good indicator of optimal rumen fermentation and ruminal pH levels.…”

Section: Effect Of Alfalfa Particle Size and Reconstitutionmentioning

confidence: 99%

Effect of particle size of alfalfa hay and reconstitution with water on intake, digestion and milk production in Holstein dairy cows

Yansari

Primohammadi

2009

Animal

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Twenty-four lactating Holstein dairy cows (12 first lactation and 12 multiparous; day in milk 5 11 6 5 days) were allotted to a randomised complete block design in a 2 3 3 factorial with four replicates per treatment to evaluate the effects of two methods of alfalfa feeding (dry and reconstituted to achieve a theoretical dry matter (DM) content of 350 g/kg) and three geometric mean (GM) particle sizes of alfalfa (9.13, 4.51 and 1.20 mm) on performance of dairy cows for a period of 28 days. Diets were offered for ad libitum intake as total mixed rations (TMR). The GM particle size, its standard deviation, and the values of physical effectiveness factor of alfalfa and TMR decreased as alfalfa particle size decreased. Reduction of particle size and reconstitution of alfalfa increased the bulk density and the functional specific gravity of alfalfa and rations. Reduction of particle size decreased insoluble dry matter, water-holding capacity, and hydration rate of alfalfa. As particle size decreased, the amount of physically effective NDF in the ration (g/kg) decreased but the daily intake of physically effective NDF (kg/day) increased. Reduction of particle size and reconstitution increased dry matter intake (DMI) and ruminal passage rate, but reduced NDF and ash digestibilities, ruminal pH, N-NH 3 , milk fat, total chewing activity, rumination and eating time, total and ruminal mean retention time, and time delay of marker. Increased functional specific gravity, from reduced forage particle size and the reconstitution of alfalfa, was the most important factor influencing DMI, milk composition, and chewing activity.

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Section: Effect Of Alfalfa Particle Size and Reconstitutionmentioning

confidence: 99%

Effect of particle size of alfalfa hay and reconstitution with water on intake, digestion and milk production in Holstein dairy cows

Yansari

Primohammadi

2009

Animal

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“…Grant et al, 1990a and1990b;Beauchemin and Yang, 2005), most of the studies used single forages in the diet, mainly silages with a relatively low dietary fiber content (23% to 32% NDF on dry matter (DM) basis). In a meta-analysis, Tafaj et al (2007) concluded that digestive effects of PS should be -E-mail: smnasrolahi@gmail.com considered in relation with particularly forage NDF in the diet.…”

Section: Introductionmentioning

confidence: 99%

Grain source and marginal changes in forage particle size modulate digestive processes and nutrient intake of dairy cows

Nasrollahi

Khorvash

Ghorbani

et al. 2012

Animal

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This study investigated the effects of, and interactions between, dietary grain source and marginal changes in alfalfa hay (AH) particle size (PS) on digestive processes of dairy cows. A total of eight Holstein dairy cows (175 days in milk) were allocated in a replicated 4 3 4 Latin square design with four 21-day periods. The experiment was a 2 3 2 factorial arrangement with two levels of theoretical PS of AH (fine 5 15 mm or long 5 30 mm) each combined with two different sources of cereal grains (barley grain alone or barley plus corn grain in a 50 : 50 ratio). Results showed that cows consuming diets supplemented with corn had greater dry matter and nutrient intakes (P , 0.01), independent of forage PS. In addition, the apparent digestibility of fiber fractions was greater for diets supplemented with corn (P 5 0.01). The feeding of barley grain-based diets was associated with greater apparent digestibility of non-fiber carbohydrates, and this variable was even greater when long AH was fed (P 5 0.04). Moreover, the feeding of long AH resulted in longer time spent eating (P 5 0.03) and higher pH (P , 0.01), as well as a tendency for higher acetate-to-propionate ratio in the rumen fluid (P 5 0.06) at 3 h post feeding. In conclusion, the results indicated that the marginal increase of PS of AH may prolong eating time and improve rumen fermentation, particularly in diets based on barley grain. Partial substitution of barley grain by corn can improve feed intake and fiber digestibility in mid-lactation dairy cows.Keywords: physically effective NDF, hay particle size, barley, corn ImplicationsThis study tested the hypothesis that grain fermentability and particle size (PS) of alfalfa hay have the potential to modify rumen conditions, digestion and performance of mid-lactation dairy cows. Indeed, the results showed an improved rumen environment and nutrient digestibility in cows fed a diet containing corn grain and long forage PS, respectively.

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“…Os consumos relativos ao peso vivo dos animais variaram de 3,35 a 3,75%, ficando dentro de uma faixa considerada normal para essa categoria animal, nas condições fisiológicas e de peso em que se encontravam, segundo os padrões de alimentação para gado leiteiro (Hoden et al, 1988;NRC, 1989;AFRC, 1993). Na Tabela 4 encontram-se os dados de consumos médios diários de proteína bruta (PB), FDN, FDA, matéria orgânica (MO) e CNF, expressos em valores absolutos (kg/cab/dia) e em relação ao peso vivo metabólico (g/kg PV 0,75 ).…”

Section: Consumo E Conversão Alimentarunclassified

“…Tendência semelhante foi observada por Mooney & Allen (1997) ao verificarem que o comprimento da partícula de silagem não influenciou a ingestão nem de matéria seca nem dos nutrientes por vacas holandesas em lactação. Grant et al (1990a) também não verificaram efeito do tamanho da partícula de feno sobre as ingestões de matéria seca e dos nutrientes das rações por vacas leiteiras em início de lactação.…”

Section: Consumo E Conversão Alimentarunclassified

“…Esses resultados são consistentes com a tese de que o tamanho da partícula dietética exerce efeito marcante sobre o teor de gordura do leite de vacas de alto desempenho (O'Dell et al, 1968;Varga, 1997). Alteração na concentração de propionato no pool ruminal possivelmente pode ser um dos principais responsáveis por esse resultado (Grant et al, 1990a). Dietas com baixa efetividade física diminuem a atividade de ruminação e o pH ruminal (Welch, 1982), aumentam a concentração ruminal de propionato e podem desencadear a queda na concentração de gordura do leite mediante mudanças nas concentrações séricas de insulina (Grant et al, 1990a,b).…”

Section: Consumo E Conversão Alimentarunclassified

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Efeito do Perfil Granulométrico das Partículas Dietéticas sobre Parâmetros de Desempenho de Vacas Leiteiras em Lactação

Bezerra¹,

Queiróz

Maldonado

et al. 2002

R. Bras. Zootec.

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RESUMO -O objetivo deste experimento foi avaliar o efeito do perfil granulométrico das partículas dietéticas sobre o desempenho de vacas leiteiras em lactação. Dez vacas leiteiras da raça Holandesa (média de 550 kg) foram distribuídas em um delineamento em switchback, em três períodos consecutivos. Os animais foram estabulados individualmente e receberam rações em mistura completa, constituída de feno de capim Tifton (50,4%) e concentrado (49,6%). O feno foi triturado em moinho comercial com peneiras de malhas de 3,2; 4,8; 7,9; 15,9; e 25,4 mm, e amostras de cada moagem foram submetidas ao separador de partículas modelo Penn State, para determinação do perfil de distribuição das partículas. Constituíram-se cinco tratamentos: T1 -100% das partículas abaixo de 8 mm; T2 -76% abaixo de 8 mm e 24% entre 8 e 19 mm; T3 -36,7% abaixo de 8 mm, 26,6% entre 8 e 19 mm e 36,7% acima de 19 mm; T4 -32% abaixo de 8 mm, 28% entre 8 e 19 mm e 40% acima de 19 mm; e T5 -26% abaixo de 8 mm, 28% entre 8 e 19 mm e 46% acima de 19 mm. Os resultados indicaram que os consumos de ração e nutrientes e a conversão alimentar não foram influenciados pelos diferentes perfis granulométricos das dietas, mas observaram-se variações na produção e na composição do leite. Verificou-se que vacas leiteiras alimentadas com dietas com perfis granulométricos intermediários produziram mais leite. A quantidade de gordura do leite produzida não foi afetada pelo perfil de distribuição das partículas dietéticas da dieta, porém vacas leiteiras alimentadas com dietas de maior granulometria produziram leite com maior teor de gordura. O processamento dos ingredientes das dietas com reduções do tamanho da partícula deve ser considerado criteriosamente, já que melhor desempenho ocorreu quando os animais foram submetidos às dietas de perfil granulométrico intermediário.Palavras-chave: fibra, consumo alimentar, conversão alimentar, granulometria, desempenho Effect of the Physical Profile of the Dietary Particles on Intake and Production Parameters of Dairy CowsABSTRACT -The objective of this experiment was to evaluate the effects of different dietetic physical profile on the performance of lactating dairy cows. Ten Holstein dairy cows (avg. 550 kg) were allotted to a switch back experimental design in three successive periods. The animals were individually housed in a tie stall and fed with total mixed rations constituted by Tifton hay (50,4%) and concentrated (49,6%). The Tifton hay was ground in commercial miller and sieved at 3,2; 4,8; 7,9; 15,9 and 25,4 mm mesh and samples from each grinding were screened through the Particles Separator Model Penn State for the determination the profile of particle distribution. Five treatments were constituted: T1-100% of particles below 8 mm; T2-76% below 8 mm and 24% between 8 and 19 mm; T3-36,7% below 8 mm, 26,6% between 8 and 19 mm and 36,7% above 19 mm; T4-32% below 8 mm, 28% between 8 and 19 mm and 40% above 19 mm; T5-26% below 8 mm, 28% between 8 and 19 mm and 46% above 19 mm. The results indicated that diet and nutrient...

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Milk Fat Depression in Dairy Cows: Role of Particle Size of Alfalfa Hay

Cited by 79 publications

References 17 publications

Effect of particle size of alfalfa hay and reconstitution with water on intake, digestion and milk production in Holstein dairy cows

Effect of particle size of alfalfa hay and reconstitution with water on intake, digestion and milk production in Holstein dairy cows

Grain source and marginal changes in forage particle size modulate digestive processes and nutrient intake of dairy cows

Efeito do Perfil Granulométrico das Partículas Dietéticas sobre Parâmetros de Desempenho de Vacas Leiteiras em Lactação

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