4 results
Slaughter traits of adult coypus grown in captivity
- C. FAVERIN, P. M. CORVA, F. A. HOZBOR
-
- Journal:
- The Journal of Agricultural Science / Volume 138 / Issue 1 / February 2002
- Published online by Cambridge University Press:
- 05 February 2002, pp. 115-120
-
- Article
- Export citation
-
The objective of the current study was to undertake a preliminary characterization of liveweight components in adult coypus at slaughter. Greenland (14 females, 7 males) and Silver (78 females, 36 males) breeds were grown on a farm south-east of Buenos Aires, Argentina. The animals were slaughtered aged 419±22 days. Liveweight at slaughter was measured and the weights of hot carcass, fur, head, liver, lungs plus heart, digestive tract (with contents) plus reproductive organs and fur length were recorded. The weights of these body components were also expressed as proportion of liveweight, except for the fur length. Data were analysed and the effects of sex, variety, reproductive state within sex and rearing management within sex were included in the model. The age of the animals at the time of slaughter was used as covariate. Breeds differed only in liver weight (P<0·05), where Greenland was 15·9% heavier than Silver; however when comparisons were made as proportion of liveweight, no differences between breeds were found in the variables analysed. Sexual dimorphism was evident in almost all of the characteristics analysed, values for males being higher than for females. Males were 29% heavier at slaughter than females and their carcasses 31·7% heavier. When body components were expressed as proportion of liveweight, male heads were heavier but fur was lighter compared to females. In conclusion, there were differences in body components due to sex but not due to breed. However, most body components when expressed as proportion of liveweight showed no significant differences.
Productivity of grazing Angus steers of different structural size
- A. J. Romera, C. A. Mezzadra, E. L. Villarreal, M. A. Brizuela, P. M. Corva
-
- Journal:
- Animal Science / Volume 67 / Issue 3 / December 1998
- Published online by Cambridge University Press:
- 02 September 2010, pp. 455-460
- Print publication:
- December 1998
-
- Article
- Export citation
-
With the objective of studying the response patterns of two biotypes of different body (structural) size to stocking rate (SR) in terms of individual growth rate (ADG), meat production per ha (PROD) and backfat thickness (BFT) under grazing conditions, 64 steers of two biotypes of the Angus breed of different body size were used: small-sized (SB: frame score of 1·3 (s.d. 0·7)) and medium-sized (MB: 2·9 (s.d. 0·6)). Four levels of SR were applied (1·8, 2·3, 2·8 and 3·3 steers per ha). The experiment lasted 241 days (April to December). Animals were weighed every 14 days, forage availability (FA) was estimated on four occasions and BFT was recorded at the end of the experiment (between 12th and 13th ribs). There were no differences between biotypes in ADG. SB tended to be earlier maturing showing higher BFT (4·39 v. 3·97 mm; P = 0·22). ADG was affected by SR and was higher at lower SR (0·612, 0·529, 0·414 and 0·375 kg/day, for 1·8, 2·3, 2·8 and 3·3 steers per ha, respectively). Individual average daily gain of the MB was more variable across the seasons of the year. None of the variables showed effects of the biotype × SR interaction but differences in ADG between biotypes as a function of the SR were observed as a trend (P = 0·29). Despite the difference in frame score between biotypes it was not possible to associate it with consistent differences in the response variables. Individual productivity (potential) of MB was not reflected in a greater productivity per surface unit. The data from this experiment do not allow the choice of a particular biotype in order to optimize the productivity of the pastoral production systems.
Energy expenditure of cattle walking on a flat terrain
- D. G. Méndez, O. N. di Marco, P. M. Corva
-
- Journal:
- Animal Science / Volume 63 / Issue 1 / August 1996
- Published online by Cambridge University Press:
- 02 September 2010, pp. 39-44
- Print publication:
- August 1996
-
- Article
- Export citation
-
A study was carried out to evaluate the effect of horizontal walking upon CO2 production rate by the carbon dioxide dilution rate technique. This was used as an indicator of animal energy expenditure. Two groups of three 18-month-old Aberdeen-Angus steers were assigned to two experiments. Average weights were 290 (s.e. 7·6) kg and 285 (s.e. 1·0) kg for experiments 1 and 2 respectively. Animals were allocated to individual pens and given 5·0 and 4·5 kg dry matter of a mixed diet for experiments 1 and 2 respectively. After a 45-day training period they were assigned to three walking treatments: 0 (T0), 3 (T3) and 6 (T2) km at 3 km/hfor 3 days in a Latin square design (3 × 3). 14C labelled sodium bicarbonate (5·4 μCi/h), diluted in carbonate-bicarbonate buffer sterile solution 0·1 mol/l, was infused for 92 h intraperitoneally with portable peristaltic pumps carried by the animals. The CO2 production rate was calculated as the ratio between the rate of infusion (μCi/h) and the specific activity of CO2 (μCi/ml CO2) in saliva samples, which were taken, in experiment 1, as an average of the day (09.00 to 16.00 h) and the night (16.00 to 09.00 h of the following day). In experiment 2 the day was divided as follows: prior to activity (09.00 to 13.00 h), activity (14.00 and 15.00 h) and post activity (16.00 h). CO2 production rate (ml CO2 per h per kg M0·75) at resting was 817 (412 kj/kg M0·75), increasing during walking to 1·46 of the resting level (T1 and T2, experiment 2) with no differences between the 1st and 2nd h of activity. One hour post activity, the CO2 production rate returned in T2 to the level of T0 but in T2 remained at 1·28 times that of T0. The average CO2 production rate during a complete day or night (experiment 1) was not affected significantly by the activity. Assuming that CO2 production rate during walking is 1·46 of resting (experiment 2) and remains at that level even at lower speeds, it can be estimated that a daily 6 km walk would increase resting energy expenditure from 1·04 when walking takes 2 h, as in this experiment (3 km/h), to 1·11 when the animal spends 6h(1 km/h).
Reproductive traits of Angus, Criollo and reciprocal crossbred females in the temperate area of Argentina
- P. M. Corva, E. L. Villarreal, C. A. Mezzadra, L. M. Melucci
-
- Journal:
- Animal Science / Volume 61 / Issue 2 / October 1995
- Published online by Cambridge University Press:
- 02 September 2010, pp. 241-249
- Print publication:
- October 1995
-
- Article
- Export citation
-
Reproductive performance of purebred Angus (A) and Criollo (C) cows and crossbred CA and AC cows in the temperate area of Buenos Aires, Argentina, was assessed through the study of reproductive rates, calving date, first insemination date, number of inseminations and weight related variables. The herd was grazed on pastures all year round. Matings were by artificial insemination with visual oestrus detection, from October to December. Heifers first calving was at 3 years of age. All traits were analysed with general linear models including, as corresponded, fixed effects of dam and calf genetic groups, calving year and month, dam physiological status, calving age and first order interactions. Female genetic group adjusted means were used to estimate direct (gl) and maternal (gM) breed differences and heterosis (hl) effects on reproductive traits. Weaning rate was mostly determined by oestrons detection rate. Due to the inhibitory effects of nursing on reproduction, female genetic group effects were significant for suckling cows only: mean oestrous detection rate was higher (P < 0·05) for crossbred cows (AC: 91·2 (s.e. 5-1) %; CA: 88·4 (s.e. 2·9) %) than for A (76·3 (s.e. 2·0) %) and C (49·9 (s.e. 3·3) %); direct breed effects favoured A (glA - g1c = 26·4 (s.e. 3·7) %; P < 0·001) and h1 was 26·7 (s.e. 3·4) % (P < 0·001). When only oestrous-detected cows were considered, direct breed effects were significant only for pregnancy rate fg1A —g1c = 8·5 (s.e. 4·4) %) whereas h1 was significant for pregnancy (8·3 (s.e. 3·8) %), calving (9·3 (s.e. 4·1) %) and weaning (10·1 (s.e. 4·1) %) rates (P < 0·05). Criollo cows calved later than crossbred (≍19 days) and A (≍15 days) cows mainly due to longer post-partum anoestrous. For calving date, direct breed effects favoured A (g1A — g1c = 20·8 (s.e. 5·9) days; P <0·0·001) and h1 was 11·4 (s.e. 2·8) days (P < 0·001). Low reproductive performance in C was not associated with live iveight at the beginning of mating. This genetic group was the latest in showing oestrous behaviour, even when not suckling. Number of inseminations was similar for the four genetic groups. These results sustain the principle of utilizing Fl Criollo-Angus cows to improve beef herd productivity, whereas they do not support the recommendation of using purebred Criollo females under this type of production system.