| Livestock Research for Rural Development 30 (10) 2018 | Guide for preparation of papers | LRRD Newsletter | Citation of this paper |
It has been well established in the literature that weaning of offspring from their dams have several effects on both physiological states. The purpose of this 24 month experiment was to establish the earliest age at weaning of the agouti offspring. Establishing this production parameter would help an intensive agouti production system by 1) allowing offspring to be able to survive at the earliest weaning period 2) for offspring to grow and develop in the post weaning phase 3) to allow dams to not lose much body condition (negative daily gains) during the lactation phase and 4) to allow dams to reconceive as fast as possible after weaning. During the 12 week growing period postpartum, offspring grew at 18.7 g/d, 18.5 g/d, 18.4 g/d and 16.1 g/d for the weaning periods 1, 2, 3 and 6 weeks respectively, hence weaning had an effect on offspring growth (p< 0.05). Average daily gains were calculated for each dam postpartum revealing that they lost -1.5 g/d, - 1.6 g/d, - 1.6 g/d and – 4.7 g/d after experiencing the weaning periods of 1, 2, 3 and 6 weeks respectively. The weaning periods of 1, 2, 3 and 6 weeks were applied and dams had successive parturitions of 15.9, 17.9, 20.4 and 23.9 weeks after, hence weaning age also had an effect on parturition interval (p< 0.05). The average weight at birth for any offspring was approximately 5.34 % of the dam’s body weight postpartum. Weaning at 1 week old had a positive impact on offspring survivability and growth while having the least negative effect on the body condition of their dams and a faster time to conception.
Key words: body condition, conception, growth, litter size, parturition, survivability
The Agouti (Dasyprocta leporina) is a Neo-tropical rodent with the potential for domestication (Brown et al 1997; Garcia 1999; Garcia 2000; Miller and Miller 1986; Mollineau, Avril and Garcia 2013). Limited information has been reported on the growth of this neo tropical animal (Mollineau et al 2013; Kleiman 1970). An intensive production model for the Agouti was proposed by Brown-Uddenburg et al (2004), but details on pre-weaning and post-weaning growth was yet to be fully explored (Boodoo and Elliotte 1992; Mohammed 2016; Ramdial and Ramdial 1978). Symthe (1970) stated that weaning of the agouti should be at 12 weeks, while Asibey (1984) suggested 8 weeks. Brown-Uddenburg et al (2004) suggested that the weaning weight of the agouti be 1096.8 g for males and 1199.7 g for females. There has been very little information on the weaning ages of agouti offspring, hence the compilation of literature from the weaning of other domestic livestock species.
The purpose of this paper was to establish the earliest age at weaning of the agouti offspring. Establishing this production parameter would help an intensive agouti production system by 1) allowing offspring to be able to survive the earliest weaning period 2) to grow and develop in the post weaning phase 3) to allow dams to not lose much body condition (negative daily gains) during the lactation phase and 4) to allow dams to reconceive as fast as possible after weaning. Establishing the “earliest age at weaning” would allow this new production parameter to be added to a list of target performance coefficients, which is the base of all intensive livestock production systems.
The animals were housed in an intensive type system. Animals were housed individually (see Picture 1.) in steel cages (15’’ length, 18’’ width and 15’’ high) and supplied with water and food on a daily basis (Brown-Uddenburg et al 2004). Pens were cleaned and washed while animals were fed, watered and observed daily.
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| Picture 1. Showing the 3 tared battery cage system for breeding pairs |
Females were weighed daily (with extreme care) until the day of parturition and eight weeks after (during pre-wean and post wean periods). Thirteen weights per dam was collected; 4 weekly weights pre partum, on the day of parturition (1) and 8 weekly weights after parturition. Females were caught using the “bag method” of catching and restraining. This method facilitates that both the animal and the handler have a barrier between them for their protection. The empty bags were used after feeding concentrates. The bag was folder down to half its height, with both hands controlling the opening. The female was scooped into the bag gently (with experience) and then weighed.
The weighing process was done by taring the bag (103g) and then weighing the females individually (AMIR Digital Kitchen Scale, 5000g, in increments of 1g). Females’ weights were recorded and stored on a spread sheet from the time of observed pregnancy to eight weeks after parturition.
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| Picture 2. Isolation of a pregnant agouti female into a maternity cage |
All young were sexed on the day of birth. Sexing entailed restraining the animal with one hand and using the thumb finger of the other hand to differentiate (see Picture 5). After sexing was done, weights were recorded on the day of birth. Animals that had more than two young and were of different and same sexes, a differentiation method was developed to identify offspring within each litter. Tagging/tattooing may have been stressful for new born offspring hence the differentiation method was developed. Mothers’ with more than two offspring of the same sex, “the hair cut method” was developed. In the case of the quadruplets, hair was cut on the shoulders and hind legs for identification purposes. Aerial right shoulder cut (male 1), aerial left shoulder cut (male 2), aerial right hind leg cut (male 3) and aerial left hind leg cut (male 4).
Weighing of young on a weekly basis required restraining, weighing and then subtracting the weight of the holding cage (502.5g) (see Picture 4) from the total weight. Offspring were left with their dams’ until the weaning ages were applied (see Picture 3).
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| Picture 3. Maternity cage with twins 10 days old | Picture 4. Restraining cage for agouti offspring before weight collection |
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| Picture 5. Sex identification of a 3 week old male agouti |
Pre-weaned data collection required young to stay with their mothers for their allotted weaning period. Mothers were fed 1000g of fresh fruit per day, usually the fruit in season or abundance (farm grown). The fruits fed were mangoes (Mangifera indica), pumpkin (Cucurbita), cucumbers (Cucumis sativus) and papaya (Carica papaya). Tropical forages such as Trichanthera (Trichanthera gigantea) and Leucaena (Leucaena leucocephala) were also fed when fruits were not available.
Dams were allowed 100g of concentrate per day (Ration 17% CP) during the gestation and lactation period. Offspring were observed on a daily basis and records of weights were taken on the same day every week at the same time, by the same person using the same scale (Etekcity 500g Digital Pocket scale, 0.01 OZ Resolution; scale: increments of 1g).
Post-weaned data collection required for all young to be separated into different cages with a feeder bowl and water container in each. All cages were of the same size (18’’ long, 15’’ width and 15’’high). Each animal was given 50g of (Ration 17% CP) and fed fruits of 500g per day for the post weaning period. All data was collected in the same fashion as the pre-weaned data collection protocols.
The data set consisted of 80 parturitions with 13 weights for each dam, and 136 offspring were born with 13 weights for each. The first test was done using the Statistical Package for Social Sciences (SPSS V.24). A general linear model (GLM) was used to predict if weaning age had any effects on offspring weight (at 12 weeks old), on dam’s body weight (8 weeks after parturition) and time to the next parturition (weeks). The second test used was the Chi square test of association to see if there were any relationships between dams’ age, parity number, successive parturition, birth weight, litter size and sex determination of offspring at birth.
There were 141 offspring born from 83 parturitions of which 136 survived from 80 parturitions. However, the 5 animals were stillborn (from 3 parturitions), which indicated that they were not subjected to any pre weaning periods, hence 100 % survivability even at the earliest time of 1 week (objective 1).
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Table 1. Effect of weaning age on offspring growth, dams body weight and time to next parturition |
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Age of weaning, weeks |
SEM |
p |
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1 |
2 |
3 |
6 |
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12 wk LW of offspring, g |
1759a |
1736a |
1733a |
1542b |
33.4 |
<0.001 |
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Dam LW 8 wk after parturition, g |
3431 |
3435 |
3448 |
3384 |
39.8 |
0.79 |
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Wks to next parturition |
15.9d |
17.9c |
20.8b |
23.9a |
0.174 |
0.0001 |
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abcd Means without common superscript differ at p<0.05 |
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The first objective was to observe if the earliest weaning time (1 week) had any effect on the survivability of the offspring. There were 141 offspring born (in 24 months) from 83 parturitions of which 136 offspring survived from 80 parturitions. However, the 5 animals were stillborn (from 3 parturitions), which indicated that they were not subjected to any pre weaning periods, hence 100 % survivability even at the earliest time of 1 week. The Agouti is very precocial and is able to survive without extensive parenting.
Of the 136 offspring there were 27 single births, 45 twin births, 5 triplet births and 1 quadruplet birth. Singles were born approximately 210 g (Brown-Uddenburg 2001) reported females being born with this weight), twins 179 g, triplets 179 g and quadruplets 174 g. Dollinger et al (2001) also reported birth weights of 80-195 g which was seen for the twins, triplets and quadruplet in this experiment. Average daily gains were calculated by using the final weight at 12 weeks old minus the weight on the day of birth divided by the number of days. Singles grew at 18.3 g/d, twins 18.1 g/d, triplets 15.3 g/d and quadruplets at 14.1 g/d. The final weight at 12 weeks of age for singles were 1992 g, twins 1695 g, triplets 1463 g and quadruplets 1363 g.
This 12 week weight collection period for dams was done to get the full range of each physiological stage from mid to late pregnancy (4 weeks before), through parturition (day of birth) to pre weaning (post parturition) and post weaning to union to possible conception. Results showed that dams that experienced weaning periods of 1, 2, 3 and 6 weeks lost – 1.5 g/d, -1.6 g/d, - 1.6 g/d and -4.7 g/d respectively though not significant (p > 0.05). This may have been so because at 8 weeks after parturition, most dams were able to regain most of their original body condition. This indicated that the earliest weaning period of 1 week had the least impact on weight loss as compared to other pre weaning periods.
The fourth objective was to observe the successive parturition of dams after experiencing the weaning periods of 1, 2, 3 and 6 weeks. This was done by applying 1 weaning period (1, 2, 3 or 6 weeks) to the dam and observing her time of possible conception and next parturition. The weaning periods of 1, 2, 3 and 6 weeks were applied and dams had successive parturitions 15.9, 17.9, 20.4 and 23.9 weeks after. These parturition intervals were also suggested by Roth-Kolar (1957) and Merit (1983). This showed that the earliest weaning period had the shortest time to next parturition (p < 0.05) leading to the conclusion that weaning at 1 week has the shortest interval between parturitions.
This experiment also contributed to the collection of other valuable data for intensive agouti production. The average litter size per dam was 1.7 offspring per litter (136 offspring/ 80 parturitions). This average litter size was also found by Weir (1974), Clark and Olfert (1986), Asibey (1984) and NRC (1991). This was a “low number” because the animal has 8 functional teats which lends to the idea that they can produce up to 8 offspring. From the 136 offspring born and survived, 75 were males and 61 were females, hence 55% of each litter were males. Males were born at 184 g while females were born slightly heavier at 187 g (Brown-Uddenburg 2001 reported females being born slightly heavier as well). Males grew at 18.1 g/d while females grew at 18.4 g/d in the first 3 months of life.
The experiment also yielded a new production factor for intensive agouti production; litter size as a percentage of dam “normal” body weight. Two important calculations were made for each litter size. The weight/s of the offspring were taken as a percentage of the maternal body weight on the day of birth and the last day of weight collection at 12 weeks old. Single born offspring weighed 5.45 % at birth and 51 % of their dams’ body weight 12 weeks after. Twins were born 10.5 % at birth and were 99.5 % after 12 weeks. Triplets were born 16.47 % at birth and were 134.3 % at 12 weeks old. Quadruplets were born at 20.6 % and were 161.3 % at 12 weeks old. From the data, it can be seen that the average weight at birth for any offspring was approximately 5.34 % of the dam’s body weight after parturition. This information was very beneficial for an intensive production system since it showed that having multiple born offspring per litter has a bigger impact on animal numbers and possible meat production.
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Received 13 January 2018; Accepted 4 September 2018; Published 1 October 2018