Implications of removing or altering the testicles of ram lambs on the financial returns from carcasses

Figures & data

Table 1  Experimental comparisons (r = ram, c = cryptorchid, w = wether, e = ewe), number of animals (n), estimated age (days, weeks or months) or liveweight target at slaughter (kg) and range of mean carcass weights collated from the scientific literature for the present study.

Study	Groups	n	Slaughter	Carcass weight (kg)
Bianchi & Garibotto (2000)	r, c, w	167	148 d	15.8–16.8
Bradford & Spurlock (1964)	r, w	141	6–8 m	18.0–30.5
Corbett et al. (1973)	r, c, w	24	21 w	14.3–14.4
Crouse et al. (1978)	r, e	138	18–66 kg	7.4–33.3
Crouse et al. (1981)	r, w	153	62, 76 kg	34.2–36.7
Dransfield et al. (1990)	r, w, e	62	20 w	17.1–18.7
Everitt & Jury (1966a, b)	r, w, e	15	28 w	14.0–16.9
Gatford et al. (1996)	r, w, e	23	187 d	18.5–23.7
Glimp (1971)	r, c, w	288	6 m	20.2–21.9
Hopkins et al. (1990)	c, w	218	137, 211 d	15.4–17.5
Kirton et al. (1982)	r, w, e	183	15, 23 w	14.6–16.0
Kromann & Ray (1967)	r, w	96	8 m	18.1–22.7
LeValley et al. (1994)	c, w	200	4, 6 m	25.5–26.4
Lirette et al. (1984)	r, w	40	120 d	11.8–17.6
Pattie et al. (1964)	r, w, e	335	4 m	15.0–16.9
Prescott & Lamming (1964)	r, w	12	10–11 m	24.3–25.9
Probert & Davies (1986)	r, c, w	170	7 m	13.5–18.1
Schanbacher & Ford (1976)	r, c, w	130	6 m	23.7–27.2
Scott Young & Dolling (1972)	r, c, w	325	4 m	17.2–19.8
Sibanda et al. (1989)	r, c, w	72	5 m	18.2–20.4
Vesely (1973)	r, c, w	101	4 m	22.3–22.4
Wilson et al. (1972)	r, c, w, e	27	6 m	19.9–24.7
Young et al. (2006)	r, w	84	122–668 d	13.7–26.1

Table 2  The effects of sex type on carcass weight of rams, cryptorchids (Crypt.) and wethers slaughtered at the same time within each experiment. S = a significant effect of sex type recorded in the original report (within rows different superscripts indicate the types that varied significantly); NS = no significant effect reported.

Study	n	Contrast	Ram	Crypt.	Wether	Breed, method, age, system
Glimp (1971)	288	S	21.5^a	21.9^a	20.2^b	Seven breeds; castration or ring-induced cryptorchidism (abdominal cavity) after birth; creep feeding then feedlot; killed at 6 months
Wilson et al. (1972)	20	S	24.7	23.9	22.2	Hampshire; knife castration or ring-induced cryptorchidism (abdominal cavity) at 25 days; pasture then feedlot; killed at 4 months
Scott Young and Dolling (1972)	85	NS	19.4	18.8	18.9	Border Leicester-Merino×Dorset Horn; castration by traction or cryptorchidism (abdominal cavity) by ring at marking; pasture; killed at 4 months
	105	NS	17.6	17.2	17.3
	135	S	19.5^a	19.8^a	18.8^b
Corbett et al. (1973)	24	NS	14.3	14.3	14.4	Corriedale; castration by ring or cryptorchidism by surgical incision of the scrotum, separation of tunica vaginalis, testis pushed through inguinal canal and ring applied to scrotum at 1–2 weeks of age; pasture; killed at 21 weeks
Vesely (1973)	101	NS	22.3	22.4	22.3	Rambouillet and Suffolk crosses; castration or cryptorchidism (abdominal cavity) by ring at birth; creep feeding then feedlot; killed 4 months
Schanbacher & Ford (1976)	130	S	27.2^a	25.9^a	23.7^b	¾-Finnish Landrace; castration or cryptorchidism (towards the abdominal cavity) by ring at 1–2 days; feedlot from weaning; killed at approximately 6 months
Probert & Davies (1986)	18	NS	17.0	16.2	18.1	Perendale; castration or cryptorchidism (located externally prior to slaughter) by ring at 4 weeks; pasture; killed at about 7 months
	26	NS	13.6	13.5	13.6
Sibanda et al. (1989)	72	NS	19.8	19.6	19.2	Merino and Dorper×Merino×Suffolk; Burdizzo castration or cryptorchidism (into the abdomen) by ring at 8 weeks; feedlot finished; killed at 5 months
Bianchi & Garibotto (2000)	167	NS	16.8	16.1	15.8	Corriedale crossbreed; knife castration or ring cryptorchidism (towards the abdominal cavity) at or within three weeks of birth; killed at 5 months

Fig. 1  Carcass weight, liveweight gain, fatness, and dressing-out% in cryptorchids (solid diamonds) and wethers (open circles) compared with rams (=100%, broken line) in individual experiments comparing all three sex types. The studies have been arranged along the horizontal axis according to the average weight of the ram carcases in each experiment.

Table 3  Mean, minimum and maximum loss or gain in financial returns resulting from producing castrate or cryptorchid compared with ram lambs, over 13–21 kg carcass weights and $2–8 payments per kg, based on the reports directly comparing rams, cryptorchids and wethers (Table 2).

	Cryptorchid			Wether
	Carcass weight (kg)			Carcass weight (kg)
Paymnent per kg ($)	13	17.5	21	13	17.5	21
Mean carcass return ($)
2	−0.52	−0.70	−0.84	−0.78	−1.05	−1.26
4	−1.04	−1.40	−1.68	−1.56	−2.10	−2.52
6	−1.56	−2.10	−2.52	−2.34	−3.15	−3.78
8	−2.08	−2.80	−3.36	−3.12	−4.20	−5.04
Minimum carcass return ($)
2	−1.30	−1.75	−2.10	−3.38	−4.55	−5.46
4	−2.60	−3.50	−4.20	−6.76	−9.10	−10.92
6	−3.90	−5.25	−6.30	−10.14	−13.65	−16.38
8	−5.20	−7.00	−8.40	−13.52	−18.20	−21.84
Maximum carcass return ($)
2	+0.52	+0.70	+0.84	+1.82	+2.45	+2.94
4	+1.04	+1.40	+1.68	+3.64	+4.90	+5.88
6	+1.56	+2.10	+2.52	+5.46	+7.35	+8.82
8	+2.08	+2.80	+3.36	+7.28	+9.80	+11.76

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