No vitamin A in cattle meat?

[Guest guest]

Hi All, &

cited Paul Bergner's article:

> Today, no cut of beef contains vitamin A, which a grass fed animal

> converts from the beta-carotene in the plants.

 

IMO, that is not correct.

 

Well formulated beef diets, even for finishers on ad-libitum concentrate

diets, contain Vitamin A supplements. Meat from cattle on good diets

has some vitamin A.

 

I agree that meat from grass-fed cattle usually has higher levels of

vitamin A than meat cattle fed high concentrate diets.

 

Vitamin A is a FAT-soluble vitamin; it tends to concentrate in FAT.

Indeed, the yellow colour of fat in grass-fed cattle comes mainly from

vitamin A.

 

Some effects of diet on beef meat and fat attributes. Source New

Zealand Journal of Agricultural Research, 1999, vol. 42, no. 3, p. 279-

287, 43 ref., ISSN: 0028-8233. Author(s) Daly-C-C, Young-O-A,

Graafhuis-A-E, Moorhead-S-M, Easton-H-S. Author affiliation MIRINZ

Food Technology and Research, PO Box 617, Hamilton, New Zealand.

Abstract Steers were fed for 9 weeks on ryegrass/clover pasture or

maize (n=6 /group), to evaluate the effects of diet on attributes of meat

and fat. Feed intake was restricted in the grain-fed group with the

intention of producing equivalent growth rates in the two treatment

groups, but this resulted in significantly slower weight gain, reduced

carcass weight, and reduced subcutaneous and intramuscular fat.

Nevertheless, the glycolytic potential (an estimate of pre-slaughter

glycogen) in the M. longissimus dorsi lumborum was approximately 20%

higher (P<0.05) in the grain-fed cattle, while the ultimate pH of the meat

was equivalent for both groups. The results suggest that grain- based

diets can increase muscle glycogen concentrations independent of the

higher calorific intake normally associated with grain diets, probably in

response to changes in rumen fatty acid production. Compared with

grain diet, pasture diet resulted in higher (P<0.01) muscle tocopherol

content, but did not influence meat colour. The dietary treatments

influenced fat colour, but both carotene content and energy intake may

be responsible for this effect. The microbiological profile of meat during

chilled storage was not affected by diet.

 

J Anim Sci. 1997 Nov;75(11):2950-4. Concentrations of selected

vitamins and selenium in bison cuts. Driskell JA, Yuan X, Giraud DW,

Hadley M, Marchello MJ. University of Nebraska, Lincoln 68583-0806,

USA. We analyzed individual cuts from clod (Triceps brachii), ribeye

(Longissimus thoracis), top round (semimembranosus), and top sirloin

(Gluteus medius) from 12 fed bison bulls for content of selected

vitamins and selenium. The bulls came from producers in the United

States and Canada and had consumed concentrate diets plus hay free

choice for at least 180 d. The mean nutrient concentrations of all of the

bison cuts combined were as follows (per 100 grams of wet weight):

..045 mg thiamin, .253 mg vitamin B6, 2.131 microg vitamin B12, no

detectable vitamin C, .848 microg vitamin A, .047 mg alpha-tocopherol,

..013 mg tau-tocopherol, and 25.464 microg selenium. The nutrient

content values did not differ (P > .05) among the cuts of meat. Cuts

from individual bulls were different (P < .05) with regard to alpha- and

tau-tocopherols, selenium, and vitamin A but not with regard to thiamin,

vitamin B6, and vitamin B12. Nutrient concentrations, with the exception

of one nutrient, of five bison from the same producer were similar. Great

variation was observed between the alpha- and tau-tocopherols,

selenium, and vitamin A contents among bison bulls but not among cuts

of meat. PMID: 9374309 [PubMed - indexed for MEDLINE]

 

Effect of grain feeding on fat colour and other carcass characteristics in

previously grass-fed Bos indicus steers. Source Australian Journal of

Experimental Agriculture, 1993, vol. 33, no. 3, p. 269-273, 23 ref., ISSN:

0816-1089. Author(s) Strachan-D-B, Yang-A, Dillon-R-D. Author

affiliation Queensland Department of Primary Industries, Animal

Research Institute, Yeerongpilly, Qld. 4105, Australia. Abstract 100

Brahman cross steers were removed from pasture and fed on a high

grain diet (80% sorghum grain) for a finishing period of 0, 35, 70, 105 or

175 days. The steers were then slaughtered and assessed for

subcutaneous fat depth, fat colour, meat colour, marbling and beta-

carotene and lutein concentrations in the fat and blood serum. The

average weight gain was 0.7 kg/day. After 35 days of grain feeding, fat

colour was decreased (P<0.05) from a score of 3.9 to 2.4 when

assessed on a scale from 0 (polar white) to 9 (creamy yellow). There

was a trend for a further decline in colour score over longer finishing

periods (averaging 1.7 after 105 days and 2.0 after 175 days), although

2 steers had a score of 6 and another had a score of 4. Steers finished

for 175 days had a higher marbling score but darker meat than those

fed for other periods (P<0.05). Subcutaneous fat depth at 105 and 175

days (17.3 mm) was greater than at 35 and 70 days (14.5 mm) and

significantly greater than at 0 days (12.5 mm). In the fat, colour score

was correlated with beta-carotene (0.61 and 0.55 in subcutaneous and

intermuscular fat, respectively) and lutein ( 0.53 and 0.52)

concentrations. Fat colour score was correlated with beta-carotene

concentration in serum (0.49). An objective assessment of fat colour

(Minolta b* value) was also correlated in the subcutaneous and

intermuscular fat with beta-carotene (0.85 and 0.80, respectively) and

lutein (0.74 and 0.73) concentrations and was correlated with beta-

carotene concentrations in the serum (0.61). It was concluded that grain

feeding reduced the fat colour in cattle, and although beta-carotene was

the predominant pigment in serum, both beta-carotene and lutein

contributed to the yellowness of the fat.

 

Short-term grain feeding and its effect on carcass and meat quality.

Source Proceedings of the New Zealand Society of Animal Production,

1997, vol. 57, p. 275, 15 ref., ISSN: 0370-2731. Author(s) Morris-S-T,

Purchas-R-W, Burnham-D-L. Author affiliation Department of Animal

Science, Massey University, Palmerston North, New Zealand. Abstract

45 Aberdeen-Angus crossbred steers weighing 540-580 kg were

assigned to 3 treatment groups. Group 1 received pasture only for 58

days; group 2 grazed pasture + 4 kg/day of a barley based concentrate

ration; group 3 were on a feedlot and fed 8 kg/day of concentrate

together with 2.0 kg/day of straw. Groups 2 and 3 each had a 28 day

preconditioning period followed by a 30 day concentrate feeding period.

Final fasted liveweights for groups fed concentrate, concentrate +

pasture and pasture alone were 546±9, 548±9, 547±8 kg respectively,

liveweight gains were 0.33±0.09, 0.42±0.09, 0.05±0.09 kg /day and

carcass weights were 293±7, 315±4 and 313±4 kg. The concentrate +

pasture and pasture only groups had greater fat depth than the

concentrate group (P<0.05). Ultimate pH was slightly lower in

concentrate fed than pasture fed cattle but there were no differences in

fat colour or meat tenderness. Plasma carotene levels were lowered by

a factor of 10 in the concentrate fed group compared to the pasture fed

group, but this did not affect fat colour.

 

 

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