Removal of Metallic Objects from Animal Feeds: Development and Studies on a new machine

^aDepartment of Clinical Sciences, College of Veterinary Medicine, Uremia University, Uremia, Iran
^bDepartment of Clinical Sciences, School of Veterinary Medicine, Shiraz University, 1731, Shiraz 71345, Iran
^cDepartment of Clinical biochemistry, College of Medicine, Tarbiat Modaress University, Tehran, Iran
^dDepartment of Clinical Sciences, Veterinary College, Science and Research Section of Azad University, Tehran, Iran

A simple machine was designed by the authors to remove different metallic objects from animal feed stuff. A series of experiments were conducted to judge the efficiency of the machine whose results revealed that the device could remove almost 100% of magnetic metallic objects and 50-62% of non-magnetic metallic material from different feed stuffs. Metallic objects were more efficiently removed from wheat, barley and alfalfa than hay. The rate of removal of nails and wire pieces was higher than that of needles.

Diet metal remover machine, Traumatic reticuloperitonitis, Iron metals, Non-iron metals.

Presence of sharp metallic objects in animal feeds causes a great economic loss to the livestock farmer. These objects once ingested by the animal especially ruminants may perforate the reticular wall causing severe ailments like vagus indigestion, diaphragmatic abscess, pneumonia, pleurisy, chronic pericarditis, and traumatic reticulo-peritonitis (TRP)[1,2]. TRP is of great economic importance as it causes severe production losses and high mortality rate in dairy cattle. Different measures are adopted to render the animal feed free from metallic objects to prevent TRP and other allied aliments. Passing of chopped feed over magnets repeatedly before being fed to cattle constitutes one of the preventive measures commonly adopted in organized dairy farms. Though, this process is time consuming and removes only a small fraction of magnetic materials, whereas non-magnetic objects are not removed at all. Similarly, the magnets administered orally to prevent or treat TRP can immobilize only those iron objects which are loose in reticulum and not embedded in to the reticular wall [3]. Rumenotomy may be the best treatment for TRP but is unnecessary in many instances because of tendency of foreign body to fall back in to the reticulum [4]. Therefore the only way to prevent TRP in dairy cattle is to make the animal feed absolutely free from metallic objects. During the present trial, an attempt was made to evolve and evaluate a device that could remove both the magnetic and non-magnetic metallic objects from different feed ingredients.

A simple machine (Fig. 1) consisting of a funnel shaped inlet (part labeled 3) attached to a tubular body (part labeled 4) equipped with an electric motor (part labeled 2) on one end, a magnet (part labeled 6) at its base and a V shaped depression (part labeled 5) towards the outlet was designed by the authors themselves.
The efficiency of this machine in removing different metallic objects from commonly used animal feeds viz. hay, alfalfa, concentrate mixtures, wheat, barley, bread, straw and pulp was evaluated by conducting a series of experiments. The various metallic objects used in the trials included nails, wires, needles, aluminum, and copper pieces. Each of the metallic objects measured about 3 cms and weights ranged from 3-10 grams.
In the first experiment nails, needles, wires and copper pieces each 50 in number and 30 pieces of aluminum were mixed separately with 1, 2 and 5 Kgs of each food stuff and loaded one by one in the machine. The motor in the machine blows air towards the feed stuff at speeds sufficient to blow the feed particles out through the outlet canal. The nails, needles and wire pieces got stuck to the floor of the canal due to magnetic attractive forces. Owing to their weight copper and aluminum pieces got trapped in the V-shaped depression towards the canal outlet. The food particles blown out through the canal were collected and loaded again in the machine. This process was repeated ten times to obtain food stuff almost free from metallic materials. The trials were conducted separately for every food stuff and each metallic material.
To make the testing conditions more realistic the number of metallic objects were decreased in the second and third experiments. The food stuffs used in the second experiment were hay, alfalfa, barley, bread and straw. Only 10 objects from each of the metallic material were mixed with the food stuff and the mixture subjected to 10 operations of the machine. Similarly, in the third experiment the number of metals in every food stuff used was reduced to 3 each and the mixture subject to only 3 operations. The food stuff used in the third experiment consisted of hay, barley bread and straw.
The data generated there upon was statistically analyzed using ‘SPSS for Windows’ statistical software.

The results of the various experiments are depicted in tables 1 to 4. It was observed that the machine could on an average remove 97.6%, 99.5% & 98.8% of needles, nails and wire pieces respectively. The rate of removal of copper was 50.2% while that of aluminum was 62.1%. The overall rate of removal got significantly increased on reducing the number of metallic objects mixed per unit quantity of the food stuff. The efficiency of the machine improved significantly when the number of each metallic objects mixed per unit quantity of feed was reduced from 50 to 10 and then to 3, making its use under actual field conditions a pragmatic possibility as incidence of metal impurities in common animal feeds is not as high as was used in experiment 1. These result are highly encouraging and favour the use of this cheap and easy to handle machine for preventing TRP especially at organized farms, since the disease is much more common in cattle fed on stored feeds especially those penned up inside far part of the year and rarely encountered in animals kept on free range grazing [1]. None the less this machine could be customized and sized to meet the requirements of not only the organized farms but also of a farmer with a small herd as well as at the feed manufacturing plant itself. Metallic objects were more efficiently removed from wheat, barley and alfalfa than from hay. The machine is able to remove up to 100% of magnetic objects and 52%-62% of non-magnetic metals. More research and further improvement in the design of the machine will increase its efficiency in removal of non-magnetic metals from feed stuff to a satisfactory level.

Table 1: Mean ± SE and percentage of removal rates of different metallic objects from 1 kg of various food stuffs subject to 10 consecutive operations of the machine

Aluminum^Y		Copper^X		Wire^X		Nail^X		Needle^X		Feed
%	mean±SE	%	mean±SE	%	mean±SE	%	mean±SE	%	mean±SE	Feed
70.6	21.2±1 c	22	11±0.7 d	95.4	47.7±0.4 a	96.2	48.1±06 a	94.4	47.2±0.9 a	Hay
82.6	24.8±0.7 c	42.2	21.3±1.7 b	100	50 a	100	50 a	98.6	49.3±0.2 a	Alfalfa
81.6	24.5±0.6 c	45.6	33.8±0.9 b	100	50 a	99.8	49.9±0.1a	99.2	49.6±0.2 a	Concentrate
28.3	8.5±0.4 c	77.4	38.7±1.4 b	100	50 a	100	50 a	100	50 a	Wheat
33.6	10.1±0.5 c	72	36±0.7 b	100	50 a	100	50 a	100	50 a	Barely
58.3	17.8±0.9 d	31.8	15.9±0.9 c	100	50 b	99.8	49.9±01 b	96	48±0.9 a	Bread
78.6	23.6±0.9 d	42.2	21.1±0.8 c	100	50 b	100	50 b	97	48.5±0.3 a	Straw
53.9	16.2±1.5 c	34.8	17.4±1.1 b	100	50 a	100	50 a	98.8	49.4±0.3 a	Pulp
60.9	18.4±0.8 c	46	24.4±0.1 b	99.4	49.7±0.1 a	99.5	49.7±0.1 a	98	49±0.4 a	Total

^X= 50 numbers; ^Y= 30 numbers; Significant difference between different letters (a, b, c, d) in rows (P < 0.05)

Table 2: Mean ± SE and percentage of removal rates of different metallic objects from 2 kg of various food stuffs subject to 10 consecutive operations of the machine

Aluminum^Y		Copper^X		Wire^X		Nail^X		Needle^X		Feed
%	mean±SE	%	mean±SE	%	mean±SE	%	mean±SE	%	mean±SE	Feed
74.6	22.4±0.6 e	30	15±0.9 d	91.2	45.6±0.7 c	96.4	48.2±0.3 b	87.4	43.7±0.6 a	Hay
81.2	24.4±0.6 b	49	24.5±2.1 b	100	50 a	100	50 a	98.6	49.3±0.2 a	Alfalfa
82.9	24.9±0.4 c	69.6	34.8±0.6 b	99.8	49.9±0.1 a	100	50 a	99.4	49.7±0.2 a	Concentrate
35	10.5±0.6 c	80.2	40.1±1.5 b	99.6	49.8±0.1 a	99.8	49.9±0.1 a	100	50 a	Wheat
46.3	13.9±0.5 c	75.6	37.8±0.6 b	100	50 a	100	50 a	99	49.5±0.2 a	Barely
63.6	19.1±1.3 b	37	18.5±1.1 b	99.4	49.7±0.2 a	99.4	49.7±0.2 a	98.8	49.4±03 a	Bread
71.6	21.6±3.3 d	28.8	14.4±0.9 c	98.8	49.9±0.1 b	100	50 b	99	48.5±0.3 a	Straw
69.3	20.8±0.8 c	66	33±0.6 b	100	50 a	100	50 a	98.8	49.4±0.3 a	Pulp
65.6	19.7±1 c	54.5	27.3±1 b	98.6	49.4±0.2 a	99.5	49.7±0.1 a	97.6	48.7±0.3 a	Total

^X= 50 numbers; ^Y= 30 numbers; Significant difference between different letters (a, b, c, d) in rows (P < 0.05)

Table 3: Mean ± SE and percentage of removal rates of different metallic objects from 5 kg of different food stuffs subject to 10 consecutive operations of the machine

Aluminum†		Copper‡		Wire‡		Nail‡		Needle‡		Feed
%	mean±SE	%	mean±SE	%	mean±SE	%	mean±SE	%	mean±SE	Feed
83.6	25.1±0.6 e	30.2	15.1±0.9 d	90.2	45.1±0.7 c	95.4	477±0.6 b	82.2	41.1±0.9 a	Hay
84.9	25.5±0.6 c	41.2	20.6±1.9 b	100	50 a	100	50 a	98.2	49.1±0.2 a	Alfalfa
77.9	23.4±0.6c	64.6	32.3±1.3 b	99.8	49.9±0.1 a	99.6	49.8±0.1 a	99.2	496±0.2 a	Concentrate
63.7	19.3±1.3 c	73.8	36.9±2.3 b	100	50 a	100	50 a	100	50 a	Wheat
29.7	9.2±0.6 c	57.2	28.6±1.2 b	100	50 a	100	50 a	99.8	49.9±0.1 a	Barely
26.3	17.9±1.2 c	36.6	18.3±0.8 c	100	50 b	100	50 b	96.4	48.2±04 a	Bread
76.6	20.3±1.7b	38	19±1.9 b	98.2	496±0.2 a	99.4	49.7±02 a	98.4	49.2±0.3 a	Straw
35	10.5±1 c	58.8	29.4±1.5 b	100	50 a	100	50 a	99	49.5±0.2 a	Pulp
59.7	18.9±1 d	50.1	24.8±1.5c	98.5	49.3±0.1 b	99.4	49.7±0.1 b	96.7	48.3±0.3 a	Total

^X= 50 numbers; ^Y= 30 numbers; Significant difference between different letters (a, b, c, d) in rows (P < 0.05)

Table 4: The percentage of removal rates of different metallic objects from 1, 2, 5 kg of different food stuffs by the diet metal remover machine subject to 10 and 3 consecutive operations of the machine

3 numbers, 3 replicates			10 numbers, 10 replicates			Food weight (kg)	Food
Aluminum	Copper	Iron	Aluminum	Copper	Iron	Food weight (kg)	Food
56	55.6	100	60	66	100	1	Hay
78	77.8	100	36	38	100	2
88.9	77.8	100	61	73	100	5
ND	ND	ND	62.8	44.4	100	1	Alfalfa
ND	ND	ND	100	77.8	100	2
ND	ND	ND	100	100	100	5
78	78	100	76	70	100	1	Barely
66.7	78	100	75	68	100	2
55.6	88.9	100	80	58	100	5
66.7	77.8	100	59	74	78	1	Bread
89	33.3	100	52	59	100	2
56	88.9	100	77	65	99	5
33.3	44.4	100	54	63	100	1	Straw
62.8	44.4	88.9	58	77	89	2
44.4	33.3	100	64	83	100	5

Fig. 1: Different parts and their function of the diet metal remover machine, large black arrows show the direction of food movement: 1) Electrical motor and blower fan: provided the blowing force of the machine; 2) Spiral part: increases the safety of machine; 3) Funnel shape part: for entering foods into machine; 4) Passing canal: the length changeable exiting place of food; 5) V shape curve: traps the non-iron metals that can not be removed by the magnet; 6) Magnet: absorbs the iron pieces;
7) Wheel: for carrying the machine; 8) Plug, wire and switch: connect to electricity and turns on and off the machine;
9) Metal surface and mounts