Utilization of nutrients by sheep as affected by diet composition and solar radiation

Muna, M.M. Ahmed; Abdelatif, A.M.

doi:10.1016/0921-4488(92)90054-8

Cited by 7 publications

(2 citation statements)

References 21 publications

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“…Thus, an effect of the increase in milk neutrophil leucocyte concentration and bacteria counts on the reduced content of oleic acid in the milk of the exposed ewes cannot be excluded. Conversely, a solar radiation effect on milk fatty acid composition, through a change in the amount of lipid precursors produced in the rumen, probably can be excluded because Muna & Abdelatif (1992) did not find significant differences in the concentration of volatile fatty acids in the rumen of shaded and non-shaded adult desert rams.…”

Section: mentioning

confidence: 99%

“…Reduced feed consumption is considered one of the most noticeable reactions of livestock to heat exposure, leading to reduced yield and poor quality of milk. However, Muna & Abdelatif (1992) and Brosh et al (1998) found that giving highenergy diets minimized the adverse effect of hot weather on feed intake in adult desert rams and in growing heifers. In addition, there is evidence that water availability and minimum night-time temperatures are critical to livestock in hot weather (Scott et al 1983 ;Aganga et al 1990).…”

Section: mentioning

confidence: 99%

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Fatty acid composition of ewe milk as affected by solar radiation and high ambient temperature

Sevi

Rotunno

Caterina

et al. 2002

Journal of Dairy Research

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Forty lactating Comisana ewes were either exposed to or protected from solar radiation and fed either in the morning or afternoon during summer in a Mediterranean climate. Individual milk samples were taken on days 7, 21 and 42 of the study period to determine fatty acid composition by gas chromatography. Exposure to solar radiation resulted in higher proportions of short-chain and saturated fatty acids in milk, primarily because of increased contents of caproic, capric, lauric, myristic and stearic acids (by 3–18%), and decreased contents of oleic, linoleic and linolenic acids (by 2–9%). As a consequence, the long to short chain and the unsaturated to saturated fatty acid ratios were significantly higher by 4 and 13% respectively in the milk of the protected ewes compared with that of the exposed animals. Provision of shade also led to an increase in the 18[ratio ]0+18[ratio ]1 to 16[ratio ]0 ratio, and to a decrease in the 12[ratio ]0+14[ratio ]0+16[ratio ]0 fatty acid group, which are regarded as reliable indexes of the nutritional property of dietary fat in reducing cholesterol levels in human plasma. Feeding time had little impact on milk fat. Our findings suggest that high ambient temperature may markedly modify the lipid composition of ewe milk and that provision of shade, but not feeding management, can improve the milk fatty acid profile in dairy sheep raised in hot climates.

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Section: mentioning

confidence: 99%

Section: mentioning

confidence: 99%

Fatty acid composition of ewe milk as affected by solar radiation and high ambient temperature

Sevi

Rotunno

Caterina

et al. 2002

Journal of Dairy Research

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Impact of heat stress on milk production, immunity and udder health in sheep: A critical review

Sevi

Caroprese

2012

Small Ruminant Research

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Effects of ventilation regimen on the welfare and performance of lactating ewes in summer1

Sevi¹,

Albenzio²,

Annicchiarico

et al. 2002

Journal of Animal Science

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A 6-wk trial was performed with thirty-six lactating Comisana ewes during the summer of 2001. The animals were divided into three groups of 12, which were designated low (LVR), moderate (MVR), and programmed (PROGR) ventilation regimens. In LVR and MVR rooms, fans provided 10 ventilation cycles of 12.5 and 25 min/h, respectively, whereas in the PROGR room, the fan was programmed to operate at 30 degrees C air temperature and 70% relative humidity. Mean ventilation rates were 33, 66, and 173 m3/h per ewe in LVR, MVR, and PROGR rooms. Air concentrations of microorganisms and dust and of gaseous pollutants were measured twice weekly. Respiration rate and rectal temperature were monitored throughout the trial at 1430. Behavioral traits of ewes were recorded once per week from 0930 to 1230. Cell-mediated immune response to phytohemagglutinin at d 3, 20, and 40 and humoral response to chicken egg albumin at d 11, 21, 30, and 40 were determined. At d 37, ewes were injected with 2 IU porcine ACTH/kg body weight(0.75) and subjected to blood sampling for evaluation of cortisol concentrations immediately before and 1, 2, and 4 h after ACTH injection. Milk yield was recorded daily. Individual milk samples were analyzed weekly for composition and renneting parameters and fortnightly for bacteriological characteristics. Averages of temperature-humidity index values were 78.9, 76.8, and 74.5 in LVR, MVR, and PROGR rooms, respectively. The LVR and MVR treatments resulted in higher NH3 and CO2 air concentrations than PROGR treatment (P < 0.05). The LVR and MVR ewes had higher rectal temperatures than PROGR ewes (P = 0.001). LVR animals also exhibited higher idling compared to PROGR (P < 0.01) and lower feeding times than MVR (P < 0.05) and PROGR animals (P < 0.01). Ewes under the LVR treatment displayed significant lower averages of antibody titers and higher plasma cortisol levels than PROGR (P < 0.01) and MVR ewes (P < 0.05) 60 min after ACTH injection. The LVR treatment resulted in lower yields of milk (P < 0.01) and reduced feed efficiency (P < 0.01) than PROGR treatment. Results suggest that a fan-ventilated system, providing ventilation cycles during the warmest hours of the day and the night at a mean ventilation rate of 66 m3/ewe per hour, may sustain the performance and welfare in lactating ewes raised in warm climates during summer. A ventilation regimen, programmed to operate over upper critical air temperature and relative humidity, may be economically unattractive under these conditions.

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Utilization of nutrients by sheep as affected by diet composition and solar radiation

Cited by 7 publications

References 21 publications

Fatty acid composition of ewe milk as affected by solar radiation and high ambient temperature

Fatty acid composition of ewe milk as affected by solar radiation and high ambient temperature

Impact of heat stress on milk production, immunity and udder health in sheep: A critical review

Effects of ventilation regimen on the welfare and performance of lactating ewes in summer1

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