La sous-alimentation chez les ruminants : ses effets sur la digestion

Doreau, M.; Grimaud, Patrice; Michalet-Doreau, B.

doi:10.20870/productions-animales.2000.13.4.3784

Cited by 9 publications

(3 citation statements)

References 39 publications

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“…This, combined with the decrease in DMI, would explain the decreased milk yield for these cows [12]. Evaluation of various studies under field conditions shows that there is an increase in digestibility in response to high temperature that may be explained by reduced DMI [16] [17] and a prolonged retention of feed in the gastrointestinal tract [18].…”

Section: Heat Stress Effectsmentioning

confidence: 99%

A Complex Interrelationship between Rectal Temperature and Dairy Cows’ Performance under Heat Stress Conditions

Rejeb

Sadraoui

Najar

et al. 2016

OJAS

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Upper limit of thermal stability and subsequent rise of thermoregulatory functions are affected by body temperature. This study was designed to determine the effects of rectal temperature (RT) on dairy cows' performance (heart rates (HR), respiratory rates (RR), milk yield (MY), dry matter intake (DMI), digestibility, plasma concentration of vitamin C under hot climate. This study was carried out in 2009, in northwest of Tunisia using 30 Holstein cows in mid lactation. The experiment was performed in spring (15th of February-15th of March: P1) and summer (1st-30th of August: P2). On each test day, temperature-humidity index (THI), RT, HR, RR, MY, DMI, digestibility and plasma VC concentration were determined. All this parameters were affected (P < 0.001) when the THI increased from 65.62 (P1) to 83.27 (P2). Regression analyses were carried out between THI index and some parameters (HR, RR, MY, DMI, digestibility, plasma concentration of vitamin C) and between RT and same parameters (HR, RR, MY, DMI, digestibility, plasma concentration of vitamin C). Characteristics of regression analyses in the two modes were different as also were R2 and r (correlation coefficient) of the regressions. R 2 in regressions on RT (R 2 (RT, DMI) = 0.92 (P < 0.01); R 2 (RT, MY) = 0.91 (P < 0.001)) was markedly higher relative to R 2 in regressions on THI (R 2 (THI, DMI) = 0.76 (P < 0.001); R 2 (THI, MY) = 0.63 (P < 0.001)). The two regressions modes suggest that increasing R 2 in regressions on RT confirms that rectal temperature constitutes a larger component of total variance of responses in dairy cows to hot environmental temperature.

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Section: Heat Stress Effectsmentioning

confidence: 99%

A Complex Interrelationship between Rectal Temperature and Dairy Cows’ Performance under Heat Stress Conditions

Rejeb

Sadraoui

Najar

et al. 2016

OJAS

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“…However, the field conditions under which the present study was carried out did not allow for indepth studies of the mechanisms underlying the observed changes in gut fill and the physiological consequences for the animal. Reviewing a number of controlled experiments, Doreau et al (2000) concluded that the physiological mechanisms that induce the changes at the level of the digestive system still need to be clarified.…”

Section: On CL U S Io Nsmentioning

confidence: 99%

Seasonal variations in gastrointestinal tract fill of grazing Zebu cattle in the Sahel

2003

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SU MMARYThe gastrointestinal tract (gut) contents of male Zebu cattle (Bos indicus) were studied in the southern Sahelian zone of Mali. Measurements were carried out on 39 animals in mid-dry season (MDS) and 15 at the end of the dry season (late dry season, LDS).After overnight fasting, the animals were weighed and then slaughtered. The different gut compartments were emptied and representative samples of their fill were analysed for contents of dry matter (all) and NDF (reticulo-rumen only).Related to fasted live weight (FLW), gut fresh matter (FM) fill (g FM/kg FLW) increased from 165 . 7¡4 . 81 g in MDS to 227 . 5¡3 . 05 g in LDS (Pf0 . 001), liquid gut contents (g fluid/kg FLW) increased from 138 . 9¡4 . 65 to 193 . 5¡2 . 49 g (Pf0 . 001) and gut dry matter fill (g DM/kg FLW) increased from 26 . 8¡0 . 88 to 34 . 0¡0 . 97 g (Pf0 . 001). Fresh matter content of the reticulo-rumen accounted for 77 % and 80 % of the entire gut FM fill in MDS and LDS, respectively. While the NDF component in reticulo-rumen fill (g NDF/kg DM) increased from 778 . 5¡5 . 63 g in MDS to 836 . 6¡6 . 37 g in LDS (Pf0 . 001), the ratio between dry matter and fluid in the reticulo-rumen (g DM/g fluid) decreased from 193 . 2¡10 . 17 g in MDS to 169 . 0¡5 . 54 g in LDS (Pf0 . 05).The data support the notion that African breeds of Zebu cattle adjust to deteriorating feeding conditions by increasing reticulo-rumen dry matter and fluid contents. In-depth studies are needed to quantify the physiological benefits resulting from this strategy.

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“…Según señalan Tyrrell y Moe (1975), la depresión de la digestibilidad con el incremento del nivel de alimentación se hace claramente patente para las dietas con alto contenido en concentrado, mientras que cuando los forrajes se ofrecen como único alimento los cambios en la eficiencia digestiva con el incremento del nivel de alimentación son más reducidos. De la revisión efectuada por Doreau et al, (2000), en la que se examinan unas 70 publicaciones que estudiaron la variación de la eficiencia digestiva en ovinos y bovinos con el incremento del nivel de alimentación en dietas de diferente contenido en concentrado, se deduce que para dietas con menos del 20% de concentrado, a una variación del nivel de alimentación entre una y dos veces mantenimiento le correspondería una disminución de la digestibilidad de la materia orgánica (%) de 2 a 3 unidades.…”

Section: Determinación De La Digestibilidad In Vivo De Forrajesunclassified

Factores que afectan a la calidad del ensilaje de hierba y a la planta de maíz forrajero en Galicia y evaluación de métodos de laboratorio para la predicción de la digestibilidad in vivo de la materia orgánica de estos forrajes ensilados

Calvete¹

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A survey was conducted in a sample of galician dairy farms from 1991 to 2002 with teh objective of studying the relationships between the ensiling techniques and herbage silage quality, being analysed about 2,600 silage samples of first and second cuts from which information about herbage types, practise of wilting and additive use, presence of rain during ensiling operations, harvester and type of silo was obtained at farm. Samples were anlysed by refemce methods for dry matter (MS), organic matter (MO), crude protein (PBt, expressed as total nitrogen x 6.25) and acid detergent fiber (FAD) contents by reference methods until 1996. Organic matter digestibility was estimated by regression using an equation based on PBt and FAD. From 1997 onwards, PBt, FAD and DM0 were estimated by NIRS. Preservation quality was estimated comparing the pH as measured on the sample and the reference pH for a good fermentation based on the equation of Haigh (1987), which relates pH to MS concentration. Valúes are not corrected for volatile losses during oven drying. The average valúes of the sample were: MS (%) 26.5±9.4, MO (%MS) 89.5±1.9, PBt 13.4±2.3, DM0 (%) 66.8±5.2 and pH 4.6±0.42. The average frequency of poor fermentation quality (42%) almost doubles that of low energy or protein content indicating that the improvement of fermentation quality of herbage silages in galician dairy farms is one of the critical points to be focused by farmers, extensionists and researchers. Year, harvest date and cut number were the known factors that explained a higher proportion of the variance of silage protein content and digestibility. Year, location, harvester type and wilting were the factors which most contributed to explain fermentation quality variability. A trend was observed towards an improvement of energy valué and preservation quality of silages from 1991 to 2002, which is positively correlated with earlier VII Summary cutting, an increase in the silage dry matter content (19.8% and 33.7 % in 1991 and 2002, respectively) and the frequency of wilting practise (40.2% of the samples in 1991 and 85.4% in 2002). It was nevertheless observed a marked dependence of silage quality on weather conditions, indicating a deficiency in wilting programming operations. It was observed that, in practice, increasing herbage dry matter content by wilting to MS levéis of 30% and higher is a most powerftil tool than additive use for a correct fermentation quality. Although, on average, one out of three silages were additive-treated, the effectiveness of its use was low, with the exception of wilted silages treated with inoculants. The lack of effect of additive use (from which formic acid was the most popular) is related, basically, to the low dosing of the product and poor homogenisation in the forage mass, since applicators were no used for the liquid additives distribution. Farm silage harvesting systems tended clearly to shorter-chop and higher performance machinery. The frequency of silage samples harvested with long-chop forage wagón (5-11 knives)...

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La sous-alimentation chez les ruminants : ses effets sur la digestion

Cited by 9 publications

References 39 publications

A Complex Interrelationship between Rectal Temperature and Dairy Cows’ Performance under Heat Stress Conditions

A Complex Interrelationship between Rectal Temperature and Dairy Cows’ Performance under Heat Stress Conditions

Seasonal variations in gastrointestinal tract fill of grazing Zebu cattle in the Sahel

Factores que afectan a la calidad del ensilaje de hierba y a la planta de maíz forrajero en Galicia y evaluación de métodos de laboratorio para la predicción de la digestibilidad in vivo de la materia orgánica de estos forrajes ensilados

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