Reduction of testicular parenchyma at marking: effect on lamb growth, carcass fatness and sexual development

1991 ◽  
Vol 31 (5) ◽  
pp. 597 ◽  
Author(s):  
DL Hopkins ◽  
RB Jackson ◽  
KL Saunders

Growth and carcass parameters were studied for 296 lambs comprising 141 males and 155 ewes. The males were either castrated (wethers) or vasectomised and hemicastrated with the parenchyma of the retained testicle reduced (cryptorchids), or they had the parenchyma of both testicles reduced (rams). Wether and ram lambs grew at a similar rate, the latter group growing significantly (P<0.05) faster to first slaughter than cryptorchid and ewe lambs. Ewe lambs grew significantly (P<0.05) slower than those from the other groups. Ewe lambs were significantly (P<0.05) fatter at slaughter than lambs in all other groups, and wether lambs were fatter (P<0.05) than the cryptorchid and ram lambs. Sexual competency of the cryptorchid and ram lambs was assessed by testicle examination, which showed that the cryptorchid lambs were not likely to produce viable sperm. In contrast, there was evidence that the treatment applied to the ram lambs would not prevent production of viable sperm, and they had the potential to sire lambs. This fertility was attributed to the retention of the scrotal sac. The technique used for the cryptorchid lambs involving scrotal ablation was deemed to offer the most potential in terms of lean tissue growth tempered against sexual competency and development of undesirable male characteristics.

1994 ◽  
Vol 58 (3) ◽  
pp. 365-372 ◽  
Author(s):  
O. Mahgoub ◽  
G. A. Lodge

AbstractForty-five local Omani ram, wether and ewe lambs were reared from birth until slaughter at 18, 28 or 38 kg live weight (five of each ‘sex’ at each weight group) on an ad libitum concentrate diet and Rhodesgrass hay.Ram lambs grew faster from birth and reached predetermined slaughter weights earlier than wether and ewe lambs. At 28 kg live weight, ram lambs had: heavier heads, feet, reticulo-rumens and livers; higher muscle and bone and lower fat proportions in the carcass; lower muscle: bone and higher muscle: fat ratios; higher proportions of carcass but lower non-carcass fat than had wether and ewe lambs. The head, feet, alimentary tract, liver and heart of Omani sheep grew at a lower rate; the skin grew at a similar rate and the carcass grew at a rate faster than empty body weight (EBW). Relative to EBW, muscle grew at a similar rate, fat faster and bone slower. Both carcass and non-carcass fats grew at a rate higher than that of the growth of EBW, with non-carcass fat growing at a higher rate than that of carcass fat. The growth rate of omental fat was the fastest followed by kidney, mesenteric, subcutaneous, tail, scrotal, intermuscular and pelvic fats respectively.This study demonstrated that Omani sheep have good potential for growth if they are managed and fed satisfactorily. Omani sheep are early maturing for which reason it is recommended that they be slaughtered at lighter weights to avoid higher fat content in the carcass. Castration in Omani sheep is not recommended for production of meat lambs under intensive systems as it resulted in reduced growth rates and deposition of excess fat at lower slaughter weights.


1996 ◽  
Vol 1996 ◽  
pp. 167-167
Author(s):  
Jennifer M.L. Anderson ◽  
G.M. Webster

Testosterone levels are generally higher in entire male sheep when photoperiod is short as this coincides with the mating period and oestrous cycles of the female. This may increase management problems of entire male sheep through augmented agonistic and sexual behaviour. By delaying puberty in the entire male lamb, management problems may be avoided, while retaining the full benefits of some testosterone secretion to promote growth and leanness. This experiment was initiated to examine the possibility that lamb growth will be enhanced under either constant long or constant short photoperiod without increased behavioural problems.At birth (mean birth date 19 March 1994 ± 3 days), 24 twin male lambs were assigned as pairs to either long (L) or short (S) photoperiod treatments alternately. One lamb from each pair was left entire (E) and the other lamb was castrated (C) at 12 hours of age using elastrator bands.


1996 ◽  
Vol 1996 ◽  
pp. 167-167
Author(s):  
Jennifer M.L. Anderson ◽  
G.M. Webster

Testosterone levels are generally higher in entire male sheep when photoperiod is short as this coincides with the mating period and oestrous cycles of the female. This may increase management problems of entire male sheep through augmented agonistic and sexual behaviour. By delaying puberty in the entire male lamb, management problems may be avoided, while retaining the full benefits of some testosterone secretion to promote growth and leanness. This experiment was initiated to examine the possibility that lamb growth will be enhanced under either constant long or constant short photoperiod without increased behavioural problems.At birth (mean birth date 19 March 1994 ± 3 days), 24 twin male lambs were assigned as pairs to either long (L) or short (S) photoperiod treatments alternately. One lamb from each pair was left entire (E) and the other lamb was castrated (C) at 12 hours of age using elastrator bands.


1988 ◽  
Vol 46 (3) ◽  
pp. 365-378 ◽  
Author(s):  
A. J. Kempster ◽  
G. L. Cook ◽  
J. R. Southgate

ABSTRACTCarcass characteristics, and the rate and efficiency of lean gain of purebred British Friesian and Canadian Holstein steers and of crossbred steers out of British Friesian dams by Charolais, Hereford, Limousin, Lincoln Red, Simmental, South Devon and Sussex sires were examined in two beef production systems. One was similar to the commercial 18-month grass/cereal system (16-month) and the other to a commercial 2-year system (24-month). The cattle were serially slaughtered at three pre-determined fatness levels, estimated by the Scanogram ultrasonic machine. The trial extended over 4 years and involved a total of 650 cattle, 398 of which had their left sides separated into tissues. Breeds were compared at equal carcass subcutaneous fat proportion determined by visual carcass assessment (SFe). Data for the two production systems were analysed separately.Sire breed differences were not detected in the regression on SFe for most characteristics (P > 0·05). Sire breeds differed in killing out and visual conformation score in both production systems (P < 0·001): Charolais and Limousin crosses had the highest values and purebred Canadian Holsteins the lowest. The overall range between sire breeds was 30 g carcass weight per kg live weight and five points on a 15-point conformation scale.Breeds with the higher conformation scores generally had higher carcass lean proportions and higher lean: bone ratios. Canadian Holsteins had a 20 g/kg lower carcass lean proportion than the British Friesians (P < 0·05).Breed crosses with larger adult body size tended to have higher lean tissue growth rates: the difference between mean values for Charolais crosses and Hereford crosses was 49 g/day (16-month) and 38 g/day (24-month). The lean tissue growth rates of the British Friesians and especially the Canadian Holsteins were low in relation to their adult body size.Limousin and Charolais crosses had the highest efficiency of lean gain (g lean per kg digestible organic matter intake). These and the other crosses were significantly more efficient than the purebred Canadian Holsteins (P < 0·05). The overall range between breeds was 20 g/kg.


1977 ◽  
Vol 25 (3) ◽  
pp. 331-341 ◽  
Author(s):  
M. Makarechian ◽  
A. Farid ◽  
N. Sefidbakht

SUMMARYBirth weights, weaning weights (75 days of age) and pre-weaning average daily gains of 291 lambs and post-weaning average daily gains, feed conversions and market weights of 136 ram lambs were studied. The lambs were of three fat-tailed Iranian breeds of sheep, Karakul, Mehraban and Naeini, and their crosses with Corriedale and Targhee rams.The crossbreds were significantly superior to the purebreds in all the traits studied, by approximately 7% in the pre-weaning traits and up to 18·4% in the post-weaning daily gain. Among the purebreds, Mehraban lambs were superior to the other two breeds in the preweaning traits and final weight.The progeny of the Targhee and Corriedale rams were similar in performance except for feed conversion, in which the lambs sired by Targhee rams were more efficient. Breed of dam had a significant effect on the pre-weaning traits and feed conversion. Mehraban ewes produced lambs with the highest pre-weaning average daily gain and weaning weight among the crossbreds, but they were the least efficient lambs after weaning.Age of dam significantly influenced the pre-weaning but not the post-weaning traits. Lambs born to 4-yr-old ewes were the heaviest and those born to 2-yr-old ewes were the lightest at birth. The lambs reared by 2-yr-old ewes had significantly lower rates of growth and were the lightest at weaning. Sex had a highly significant effect on the pre-weaning traits in favour of the male lambs.


1993 ◽  
Vol 71 (4) ◽  
pp. 930-938 ◽  
Author(s):  
Anders Karlsson ◽  
Ann-Charlotte Enfält ◽  
Birgitta Essén-Gustavsson ◽  
Kerstin Lundström ◽  
Lotta Rydhmer ◽  
...  

1999 ◽  
Vol 69 (1) ◽  
pp. 81-92 ◽  
Author(s):  
A. F. Carson ◽  
B. W. Moss ◽  
R. W. J. Steen ◽  
D. J. Kilpatrick

AbstractThis study investigated the effects of the percentage of Texel or Rouge de l’Ouest (Rouge) genes in lambs (0, 50, 75 or 100%; the remainder being Greyface (Border Leicester × Scottish Blackface)) on lamb carcass characteristics and meat quality. Ewe lambs were slaughtered at 34, 40, 46 and 52 kg and ram lambs were slaughtered at 40, 46, 52 and 58 kg live weight. Dressing proportion increased (P < 0·001) by 0·53 and 0·27 g carcass weight per kg live weight for each 1% increase in Texel or Rouge genes respectively. Carcass conformation classification increased (P < 0·001) by 0·016 and 0·007 units (on a five-point scale) for each 1% increase in Texel or Rouge genes respectively. Carcass fat depth measures were reduced by Texel and Rouge genes such that at a constant fat depth end point, carcass weight could be increased by 0·029 and 0·023 kg for each 1% increase in Texel or Rouge genes. Carcass lean content increased (P < 0·001) by 0·99 and 0·27 g/kg for each 1% increase in Texel or Rouge genes. Subcutaneous fat content was reduced (P < 0·001) by 0·36 and 0·29 g/kg for each 1% increase in Texel or Rouge genes. Intermuscular fat content was reduced (P < 0·01) by 0·38 g/kg per 1% increase in Texel genes, whereas Rouge genes had no effect. Similarly, bone content was reduced (P < 0·01) by Texel genes only (0·31 g/kg per 1% increase in Texel genes). Warner-Bratzler shear force values showed a quadratic effect with increasing Texel and Rouge genes, with an initial decrease from 0 to 50% followed by an increase to 100%. Cooking loss increased (P = 0·05) as the percentage of Rouge genes in lambs increased. Increasing the percentage of Texel or Rouge genes significantly increased L* values (P < 0·01 and P < 0·05 respectively), b* values (P = 0·05 and P< 0·05 respectively) and H° values (P < 0·001).


2002 ◽  
Vol 75 (3) ◽  
pp. 459-468 ◽  
Author(s):  
L. E. R. Dawson ◽  
A. F. Carson ◽  
L. O. W. McClinton

AbstractAn experiment was undertaken to compare the productivity of crossbred ewes, produced by crossing Texel sires with Rouge de l’Ouest (Rouge) dams and Rouge sires with Texel dams, relative to purebred Texel and Rouge ewes. The purebred and crossbred ewes were crossed with Rouge and Texel sires. The proportion of productive ewes was similar in the purebred and crossbred ewes with an average figure of 0·92. Irrespective of crossing sire, Rouge ewes produced 0·48 more lambs per ewe lambed than Texel ewes (P < 0·001). The two crossbred ewe types (Texel ✕ Rouge and Rouge ✕ Texel) each produced similar numbers of lambs (on average 1·92 lambs per ewe lambed). Individual heterosis values for ewe fertility and prolificacy were small and not significant (–1·67 for the proportion of productive ewes and –3·14 for the number of lambs born per ewe lambed). Maternal heterosis values were also not significant but were of larger magnitude (6·26 for ewe fertility and 3·12 for prolificacy). Lamb mortality (number of lambs born dead per ewe lambed) at birth was similar for purebred Rouge (0·44) and Texel (0·30) ewes and was significantly reduced by crossbred matings and mating the crossbred ewes (individual heterosis –30·68, P < 0·10; maternal heterosis –80·23, P < 0·001). Individual and maternal heterosis values for lamb growth rate from birth to six weeks were 8 (P < 0·05) and 4 (P > 0·05) respectively. Lamb growth rate from birth to weaning was significantly lower in lambs from Texel ewes compared with those from the other genotypes (P < 0·05). Individual and maternal heterosis values for live-weight gain from birth to weaning were 5 (P < 0·10) and 5 (P < 0·01). The results of the current study demonstrate the superior performance of purebred Rouge ewes compared with purebred Texel ewes in terms of prolificacy and lamb growth rate from birth to weaning. However, both breeds had high lamb mortality at birth. Crossbreeding led to the production of hybrid ewes which had relatively high prolificacy with low levels of dystocia and lamb mortality.


2016 ◽  
Vol 37 (4) ◽  
pp. 2123 ◽  
Author(s):  
Sérgio Carvalho ◽  
Luana Cortes Zago ◽  
Cleber Cassol Pires ◽  
Andressa Ana Martins ◽  
Rafael Sanches Venturini ◽  
...  

In this study, we evaluated the tissue composition, the ratios between different issues, and the allometric growth of tissues from the commercial cuts neck, shoulder, rib, and leg, and of the carcass of Texel lambs. Thirty uncastrated male lambs born from single calvings were used in this experiment. Lambs were weaned, confined individually, and distributed into five treatments with six replications. Each treatment consisted of a predefined slaughter weight (T23 – initial slaughter, T25, T30, T35, and T40). The proportion of bone decreased linearly in the shoulder, rib, and legs, but remained constant in the neck. The proportion of muscle decreased in the rib, whereas in the other cuts it remained constant. The percentage of fat increased as the slaughter weight of the lambs was increased, for all cuts. In all cuts and in the carcass, bone and muscle showed early growth (b &lt; 1), whereas fat displayed late growth (b &gt; 1). The proportion of bone decreased and fat increased linearly in the carcass, and the proportion of muscle was not influenced by the slaughter weight of the lambs. The muscle/fat ratio decreased in all cuts, and consequently in the half-carcass, as the slaughter weight was increased. The muscle/ bone ratio increased in the shoulder, rib, leg, and half-carcass, but there was no significant effect on the neck. The bone and muscle tissues showed early growth, whereas the fat had late growth in the different commercial cuts and carcass of Texel lambs. The tissue growth pattern of the shoulder may be representative of the allometric growth of the different carcass tissues. An increase in the slaughter weight of Texel lambs leads to a reduction of the muscle/fat ratio, due to the higher deposition of fat in the carcass of these animals.


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