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This literature review focuses on the milk yield and milk composition of rabbits and the non-nutritional factors affecting both quantity and quality. Actual highly efficient hybrid does have an average daily milk yield of 250 g or 60 g/kg of live weight during the 4-weeks lactation period. However, compared with cow and sow milk, rabbit's milk is much more concentrated in fat (12.9 g/100 g), protein (12.3 g/100 g) and energy (8.4 MJ/kg) which explains the extremely rapid growth of the young (weight x 6 after 3 weeks). Characteristic of rabbit milk is also the nearly absence of lactose (<2 g/100 g). At peak lactation, protein output per kg metabolic weight (13.4 g/day/kg 0.75 ( exceeds even those of Holstein milk cows. The non-nutritional factors having the largest impact on the milk yield are the number of suckling kits, the parity order (primiparous vs. multiparous) and the gestation overlapping degree (rapid decline after 17-20 days of gestation). However, also through the reduction of feed intake, heat stress has a detrimental impact especially when the night temperature remains above 25°C. Rabbit milk lipids are highly saturated (70.4% SFA) due to the high content of C8:0 - C12:0 (50% of total FA) and further characterised by nearly equal quantities of oleic and linoleic acid and an w-6/w-3 ratio around 4. Finally some data about the amino acid, milk proteins including the immmunoglobulins, mineral and vitamin composition are presented
Content may be subject to copyright.
World Rabbit Sci. 2006, 14: 205-230
© WRSA, UPV, 2003
Correspondence: L.Maertens,
Received May 2006 - Accepted October 2006.
ABSTRACT: This literature review focuses on the milk yield and milk composition of rabbits and the non-nutritional
factors affecting both quantity and quality. Actual highly efficient hybrid does have an average daily milk yield of 250
g or 60 g/kg of live weight during the 4-weeks lactation period. However, compared with cow and sow milk, rabbit’s
milk is much more concentrated in fat (12.9 g/100 g), protein (12.3 g/100 g) and energy (8.4 MJ/kg) which explains
the extremely rapid growth of the young (weight × 6 after 3 weeks). Characteristic of rabbit milk is also the nearly
absence of lactose (<2 g/100 g). At peak lactation, protein output per kg metabolic weight (13.4 g/day/kg0.75)
exceeds even those of Holstein milk cows. The non-nutritional factors having the largest impact on the milk yield are
the number of suckling kits, the parity order (primiparous vs. multiparous) and the gestation overlapping degree
(rapid decline after 17-20 days of gestation). However, also through the reduction of feed intake, heat stress has
a detrimental impact especially when the night temperature remains above 25°C. Rabbit milk lipids are highly
saturated (70.4% SFA) due to the high content of C8:0 – C12:0 (50% of total FA) and further characterised by nearly
equal quantities of oleic and linoleic acid and an w-6/w-3 ratio around 4. Finally some data about the amino acid, milk
proteins including the immmunoglobulins, mineral and vitamin composition are presented.
Key words: rabbit, milk, quantity, quality, affecting factors, review.
Rabbit does are in general allowed to nurse their kits till weaning age (4-5 weeks of age). Kits are until
18-19 days of age exclusively depending from the milk of their mother (Maertens and De Groote,
1990; Fortun-Lamothe and Gidenne, 2000). Newborn rabbits have high energy requirements and a
low thermal isolation. Therefore early liveability and growth performances are closely related to the
quantity and quality of the milk ingested (Lebas, 1969 and 1976; McNitt and Moody, 1988; Fraga et
al., 1989; Szendrö and Maertens, 2001). Recently, this relationship has been stressed by Szendrö et
al. (2002) using 2 nursing does per litter.
The lactation requires a great energy effort of the doe and is closely related to some variables as
corporal condition, fecundity and foetal growth (Fortun-Lamothe and Bolet, 1995; Pascual et al.,
2003; Xiccato et al., 2004). Moreover, genetic selection in maternal lines has focussed mainly on
prolificacy resulting in parental lines with a litter size of over 10 kits (Tudela et al., 2003). Consequently,
demands and requirements of does for milk yield have increased greatly. However, strains were
primarily successfully selected for increased litter size but weaning weight of kits dropped
(Rochambeau, 1998). This indicates that the relative increase of milk yield was smaller than that of
litter size, leading to smaller amounts of milk available per kit (Szendrö and Maertens, 2001).
Maertens L.*, Lebas F., Szendrö Zs.
*Inst. for Agricultural and Fisheries Research, Animal Science Unit, 9090 MELLE, Belgium.
Cuniculture, 87a Chemin de Lasserre, 31450 CORRONSAC, France.
Univ. of Kaposvár, Faculty of Animal Science, 7400 KAPOSVAR, Hungary.
Rabbit milk is collected for the production of recombinant proteins in transgenic animals (Castro et
al., 1999; Bõsze and Houdebine, 2006). The high protein content of rabbit milk together with the high
yield/kg live weight and the rapid reproduction rhythm are attractive characteristics to use rabbits
for this purpose. Nevertheless, milking of rabbit does remain an exceptional goal. Consequently,
information relating with milk yield and composition remains relatively scarce although interesting
work was already executed, mainly in France, already 35 years ago (Lebas, 1968, 1969, 1971 and 1976;
Lebas et al., 1971). The present review intends to update this information and to discuss the main
factors influencing milk yield and milk composition of does used for meat production. Dietary effects
on milk yield and composition were recently reviewed by Pascual et al. (2003) and thus they should
be only marginally mentioned in this review.
Direct method
In larger animal species (e.g. cows, sheep), mechanical or manual milking is used as direct method to
measure milk production. Also for rabbits milking machines were developed and described (Lebas,
1970; Schley, 1975; Marcus et al., 1990). Milking or sampling is always done after a 24-hour separation
of mother and kits avoiding the free suckling of kits. Females have to be treated with oxytocine in
order to stimulate the milk ejection. When the females are fixed in a comfortable position with suitable
milking equipment, equivalent or higher amounts than that ingested by the kits at one suckling can
be collected (Lebas, 1970). This methodology is generally used for the collection of milk from transgenic
rabbits (BioProtein Technologies, 2006). However, in animal research studies, this methodology is
not used to determine the milk yield capacities during the whole lactation period.
Indirect measurement
The nursing behaviour of the rabbit is characterised by a daily short event of only 3-4 minutes
(Cross, 1952; Hudson et al., 2000). Although most does show a strong circadian basis with one
nursing event every 24 hours, a limited number of females nurse their kits more than once a day
(Zarrow et al., 1965; Hoy and Selzer, 2002; Matics et al., 2004). However, it has not been demonstrated
that more milk is produced or that kits grow faster when the doe performs (or is allowed or not) more
than one nursing a day (Hudson et al., 2000). For example Zarrow et al. (1965) have observed exactly
the same daily gain, day after day, from 2 to 30 days after kindling for kits able to suckle their mother
freely, only once or twice a day. An explanation could be found in the observations of Calvert and
Knight (1982) that milk secretion is performed at a constant speed during the 24 hours following a
nursing and thereafter dropped dramatically. Nevertheless with the double suckling method, Gachev
(1971b) observed a slight reduction of milk production during the last 6 hours fraction of the 24 hours
period (19.4% of the total yield vs 24.8% to 28.0% for the 3 others 6 hours periods).
As a consequence of the nursing behaviour, daily milk yield can easily and accurately measured by
determining the weight difference of the doe before and after nursing (Lebas, 1968). This weight-
suckle-weight method is widespread used for research purposes and has an advantage over weighing
of the kits. Kit weighing is more difficult because they are nervous and the accuracy is lower because
kits show some urine losses even during the suckling event (Lebas, 1971).
During the first stage of the lactation period, the next box can be closed and daily opened to nurse
the kits and to determine the milk yield. However, once the kits starts to consume solid feed, from day
18 onwards (Fortun-Lamothe and Gidenne, 2000), housing of the kits has to be in a separated cage or
in an adapted cage to allow both the milk yield determination as the normal development of the kits
(Fortun-Lamothe et al., 2000).
The indirect measurement of the milk yield is a time and labour consuming method. However, when
only 3 measures per week are executed, total yield can be calculated with a high accuracy (R²=0.982;
RSE=5.2) (Fernández-Carmona et al., 2004). Using a quadratic regression model obtained from 3
measurements per week (9 in total), Fortun-Lamothe and Sabater (2003) estimated daily and total milk
yield of each doe in the 0-21 days lactation period.
Estimation based on the growth of the suckling kits
There exist a high correlation between the milk production and the growth of the kits because rabbit
kits do not show significant feed intake before the age of 18-19 days (Maertens and De Groote 1990;
Fortun-Lamothe and Gidenne, 2000). The highest correlations reported are for the period between
birth and 21 days of age and amount to 0.90 (Lebas, 1969), 0.91 (Fortun-Lamothe and Sabater, 2003)
or even 0.99 (Lukefahr et al., 1983). Weight gain of the litter at a later stage is much less correlated
with the milk yield in the corresponding period (Lebas, 1969). Although litter weight at 21 days is
highly correlated with the milk yield (R²=0.917; RSE=11.5) (Fernández-Carmona et al., 2004), litter
weight gain at 21 days is a better predictor of the doe milk yield than litter weight at 21 days (Fortun-
Lamothe and Sabater, 2003).
For actual high productive hybrid does the following equation was drawn (Fortun-Lamothe and
Sabater, 2003):
Milk yield 0-21 d (g) = 1.69 × weight gain of the litter 0-21 d (g) + 362 (r=0.91)
Collection of samples
There are different methods to collect milk samples. Apart from a milking machine, samples can be
collected by manual milking by gently pushing on the mammary gland. An experienced person can
collect during 1-2 minutes easily 20 ml even without injection of oxytocin (authors’ personal
observations). Although Lebas (1971) did not find significant differences in the composition of 4
consecutive samples of 45-70 g, he recommends for analysis a sample quantity of at least a quarter of
the total amount present. However, it was never proved that the composition of the first 20 g by e.g.
hand milking is not representative for the total quantity.
Another milk collection method is to take, immediately after the nursing, a sample out of the kit’s
stomach by means of an orally introduced stomach tube (Fraga et al., 1989; De Blas et al., 1995). This
method is easy but some contamination may occur with gastric secretions and with the residual milk
still contained in the stomach even after a 24 hours period (authors’ personal observations).
The usual lactation period of does is between 4 and 5 weeks depending on the reproduction rhythm
and management system. However, mainly for experimental purposes, early weaning is sometimes
executed and a shorter lactation period is considered (Xiccato et al., 2004). In absence of a new
pregnancy, milk production can continue up to 6 weeks or even a longer period (Cowie, 1968; Lebas,
Papers dealing with milk yield of does are quite limited and most of them are linked with nutrition
experiments. In Table 1 only papers that have measured the milk yield and when does were fed ad
libitum are considered. Milk yield is often expressed in different ways: i) as the total quantity produced
in a certain period ii) as an average production during a period or iii) as the sum of a limited number
of determinations. Therefore, it is not easy to compare the data in the different papers including milk
yield data. Moreover, many of the results published are strongly influenced by diet or does genotype
but also by reproduction rhythm, environmental temperature, parity, and so on. A detailed discussion
about their impact on milk yield is presented below.
Based on the data of Table 1, actual strains used for commercial meat production have a 28-days milk
yield in their first lactation of about 5.5 kg (Xiccato et al., 1995; Pascual et al., 2002b, Maertens et al.,
2006). Multiparous hybrid does, nursing 9-10 kits, have a yield that exceed 7.0 kg during a 28-days
lactation period or 250 g/d or around 60 g/d when expressed per kg of live weight (LW) (Fortun-
Lamothe and Sabater, 2003; Xiccato et al., 2005; Maertens et al., 2006).
Table 1: Descrip tion o f the p ap e r s d e a ling with milk yield.
Reference Diet
Strain/ Line Parity
No. of
lacta t io ns
Milk yield
Tota l
Lebas, 1968 Reproduction diet Fauve de
Different 8-9 143 0-42 7090 242 169 42.3
Partridge and
Allen, 1982
a) Low protein diet
b) Medium protein diet
c) High protein diet
New Zealand
x C a lifo r nia n
2+ 8 6
Luke fahr et al.,
Reproduction diets NZW
Cal x NZW
NZW x Cal
Different NSLS1In total:
Maertens and De
Groote, 1988
Low energy diet
Medium energy diet
High energy diet
Hybrid (Elco) 2-5 8 15
Fraga et al.,
Different reproduction
Californian x
New Zealand
McNitt and
Lukefahr, 1990
Reproduction diet Californian
New Zealand
White Satin
Different NSLS 19
Mohamed and
Szendrö, 1992
Reproduction diet Californian
(3.8 kg)
Khalil, 1994 Commercial diet Giza White
(3.2 kg)
Different 222 0-35 3493 100 31.3
Taboada et al.,
L-lysine level:
a) 0.64%
b) 0.68%
c) 0.71%
d) 0.76%
e) 0.82%
New Zealand
x C a lifo r nia n
2+ NSLS 14
De Blas et al.,
Lactation diets with
different starch and fat
New Zealand
x C a lifo r nia n
2+ NSLS 16
Xiccato et al.,
Medium ene rgy level
High energy level
High fat level
De Blas et al.,
Threonine le ve l:
a) 0.54%
b) 0.58%
c) 0.63%
d) 0.68%
e) 0.72%
2+ NSLS 16
Continuation Table 1.
Pascual et al.,
a) Starch rich
lac tation diet
b) Soy oil rich
lac tation diet
(V x A rabbit
191 236 50.7
Pascual et al.,
a) Control
reproduction diet
b) With added
vegetable fat
c) With added animal
(V x A rabbit
2+ 8 or 11 40
Pascual et al.,
a) Low energy diet
b) Medium energy diet
c) High energy diet
(V x A rabbit
± 8 21-46
Xiccato et al.,
Lactation diet Hybrid
1 8 23 0-30 6150 205 52.6
Fraga et al.,
Different reproduction
Californian x
New Zealand
Pascual et al.,
a) Reproduction diet
b) Alfalfa based diet
c) Alfalfa based +
animal fat
(V x A rabbit
1+2 8 51
Pascual et al.,
a) Animal fat enriched
b) Vegetable oil
enriched diet
c) Starch rich diet
(V x A rabbit
Pascual et al.,
a) Control
reproduction diet
b) High fibre fo llowe d
by control diet
(V x A rabbit
Fo rtun-Lamothe
and Sabater,
Standard reproduction
2+ 10 50 0-21 5300 315 252 62.2
Khalil et al.,
not defined Ga bali x
Spanisch V
line crosses
(3.5 kg)
1-2+ NSLS 2141 0-28 4331 155 44.3(3)
Xiccato et al.,
Lactation diet Hybrid
1; 2; 3 922
Xiccato et al.,
Lactation diet Hybrid
2+ 10 31 23 0-21
Zerrouki et al.,
Reproduction diet Kabylian
(2.8 kg)
1-4+ 2-8 299 0-21 2180 147 104 37.2(3 )
Maertens et al.,
a) Lactation diet
b) w-3 lactation diet
(4.2 kg)
1-6 8-9 179
Maertens et al.,
Lactation diet Hybrids 1 2 7.4
1 NSLS : no t sta nd a rdise d litte r size; 2 Recalculated using the given average doe live weight (LW); 3 Recalculated using average strain LW if
data were lacking
Average peak lactation of multiparous commercial hybrids is around 320 g/d (Fortun-Lamothe and
Sabater, 2003; Xiccato et al., 2005; Maertens et al., 2006). Expressed per kg LW, peak yield is around
75 g/d and exceeds those of milk cows (Kay et al., 2005) or sows (Lauridsen and Danielsen, 2004)
(Table 2). When expressed per kg of metabolic weight, which is preferred by some scientists because
of its physiological basis (but not really accurate because it is a production of a milk mass by a body
mass), milk production of rabbit is still lower than that of productive Holstein cows or hybrid
sows.(Table 2).
Lactation stage
Average lactation curves of multiparous hybrid does at different physiological status are presented
in Figure 1 (adapted from Lebas, 1968; Szendrö et al., 1985; Xiccato et al., 1995; Maertens et al.,
The top lactation is situated on day 18-19 after kindling (Lebas, 1968; Maertens and De Groote, 1991;
Fortun-Lamothe and Sabater, 2003; Casado et al., 2006). However, in case of deficiencies in amino-
acid supply (De Blas et al., 1995; Taboada et al., 1994) or when primiparous does are submitted to the
intensive reproduction rhythm, the lactation peak is reached 2-3 days earlier (Maertens and De
Groote, 1991; Xiccato et al., 1995; Pascual et al, 1999b). Moreover, Lebas (1968) observed a breed
difference; Fauve de Bourgogne does reached top lactation 3-4 days (day 21) later than Californian
The lactation curve of rabbits is asymmetric with a convex ascending and a concave descending
period (Lebas, 1968). The principle component analysis executed by the same author (Lebas, 1976)
using 975 lactation curves, revealed that 74.3% of the variability between lactation curves could be
explained by 3 main factors. The most important was the total daily amount, followed by a factor
expressing the asymmetry of the curve and finally a factor determining the amplitude of the curve,
explaining respectively 58.3, 10.1 and 5.8% of the variability.
Table 2: Comparison of daily milk yield, fat and protein output at lactation peak between multiparous
high productive rabbit does, cows and sows.
Hybrid rabbit does1Holstein cows2Hybrid sows3
Live weight (kg) 4.2 650 230
Peak milk yield (kg) 0.320 47.5 8.9
Milk fat (g/100 g) 12.9 3.7 6.5
Milk protein (g/100 g) 12.3 2.84 5.1
Output/kg live weight (LW)
Milk (g/d) 76 73 39
Fat (g/d) 9.8 2.7 2.5
Protein (g/d) 9.4 2.1 2.0
Out p ut/k g metabolic weight (LW0.75)
Milk (g/d) 109 369 151
Fat (g/d) 14.1 13.7 9.8
Protein (g/d) 13.4 10.5 7.7
1Based on data of Table 1 and Table 5; 2Kay et al. (2005); 3Lauridse n and Danielsen (20 04)
Recently Casado et al. (2006) proposed different empirical models for the 28-day lactation curve,
based on 550 lactation records. The beta-modified equation had a better fit suitability than the
quadratic model and the advantage of a greater biological interpretation of its parameters. The
following prediction model is proposed (Casado et al., 2006):
Milk yield (g/day) = k × (day/30)a × (1 (day/30))b
where k regulates the height of the curve and a and b regulate the milk yield of the ascending and
descending period, respectively. In the equation given by these authors, values for the parameters k,
a and b are respectively 470.156; 0.489 and 0.371 (R²=0.986, RSD=5.648).
There are only few data available concerning the weekly yields of does. When we recalculate the
data of Lebas (1968) based on 143 lactations, on a 4 weeks lactation basis, 15.9, 24.4, 32.0 and 27.3%
were produced in weeks 1 till 4, respectively. The analysis of Fernández-Carmona et al. (2004), based
on 943 records obtained in their experimental farm, revealed a similar weekly partition of 18, 27, 30 and
25%, respectively for weeks 1-4. However, the partition between lactation weeks is strongly dependent
if the doe is concurrent pregnant or not (Lebas, 1972; Xiccato et al., 1995). According to Lebas
(1968), if the litter weaning is delayed to 35 or 42 days post parturition, and if the doe is not pregnant,
the milk production during the 5th or the 6th week represents 19.5% or 12.9% respectively of the 0-28
days milk production.
Gestation overlapping degree
The negative impact of the gestation overlapping on milk yield was already clearly demonstrated by
Lebas (1972) and confirmed in several other studies. In practise only 3 reproductive rhythms are
frequently used: intensive with complete overlapping, semi-intensive with overlapping from 11 days
after parturition and a rhythm without significant overlapping. Does submitted at the intensive
reproduction rhythm (mating or artificial insemination (AI), within 48 h after kindling) begin showing
decreased milk production after 17 days (Maertens and De Groote, 1991; Fraga et al., 1989; Xiccato
et al., 1995 and 2005; Pascual et al. 2002a) to 19 days (Lebas, 1972; Partridge et al., 1986a; Szendrö et
al., 1985; Kustos et al., 1996; Xiccato et al., 1995) of lactation with a sharp and quite linear decrease
during the last 10 days of pregnancy (Figure 1). However, in primiparous does that are concurrently
pregnant shortly after parturition, this decline starts already at day 16-17 of the lactation (Maertens
and De Groote, 1991; Xiccato et al., 1995; Pascual et al., 2002a). Moreover in some experiments peak
yield was lower in does pregnant immediately after parturition compared to does not pregnant before
day 11 post parturition (Szendrö et al., 1985; Xiccato et al., 1995).
Milk yield (g/d)
Figure 1. Lactation curve
of multiparous does
according to their
physiological status.
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35
lactation day
Not pregnant
PP pregnant
11d PP pregnant
The decrease in milk yield due to the gestation overlapping during the entire 28-day lactation period
was between 19-22% according to the diet (Maertens and De Groote, 1988) and in line with the 20%
decrease determined by Xiccato et al. (1995). Although the milk yield decrease between 21 and 28
days was 38% in the experiment of Pascual et al. (2002a), for the whole lactation period only a 9%
lower yield was determined in post-partum pregnant females compared to does without gestation
overlapping. When compared to females pregnant from day 9 post parturition off, total milk yield was
9% lower in females with complete gestation overlapping (Fraga et al., 1989).
When females are submitted to the usual semi-intensive reproductive system with AI 11 days
postpartum, the milk yield is only slightly decreased from day 25 off compared to females inseminated
after weaning (Szendrö et al., 1985; Casado et al., 2006). The decrease is limited to around 25 g during
the last days of a 28-day lactation period. If weaning is performed later, a sharp decline of the milk
yield is observed with virtual dried up does after 35 days of lactation (Figure 1). However, when no
concurrent gestation occurs, still a significant (70 g) yield was measured at day 38 (Szendrö et al.,
The decline in milk yield due to the gestation overlapping is a result of the pregnancy requirements
that consistently increase with the exponential foetal development (Parigi-Bini and Xiccato, 1998),
the increasing volume of the uterus reducing the voluntary feed intake and due to hormonal changes
caused by the imminent kindling contrasting with those for lactation.
Number of suckling kits
In various studies it has been demonstrated that the number of suckling kits is the main factor
affecting milk yield of does and by consequence the intake of the suckling kits (Lebas, 1969; Torres
et al., 1979; Partridge and Allen, 1982; McNitt and Lukefahr, 1990; Pascual et al., 1996 and 1999a). In
Figure 2, the relationship between the number of suckling kits and the milk yield is presented (Lebas,
1987). Based on these data, the following quadratic model was fitted between milk yield and number
of suckling kits:
Milk yield (g/day) =37.47x -1.56N² (R²=0.999, RSD=3.77)
where N is the number of kits (range=5-11).
In the experiments of Partridge and Allen (1982), does allowed to nurse 8 kits had a 24.1% higher yield
compared to does with only 4 kits. Mohamed and Szendrö (1992) found an increase with 3.3% and
5.4% of the milk yield with increasing litter sizes from 6 to 8 and 10 kits, respectively. Pascual et al.
Milk yield (g/d)
Figure 2. Relationship between the number of suckling kits and milk yield (Lebas, 1987).
N° of suckling kits
(1996) determined even a difference of 32% in milk yield in favour of litters of more than 10 kits
compared to litter sizes of 7-8 kits.
The effect of the number of suckling kits on milk yield was even clear if litter size was reduced from
10 to 4 kits at day 16 of the lactation (Fortun-Lamothe and Gidenne, 2000). Milk yield between 16 and
32 days of lactation dropped by 45% in does nursing only 4 kits. This indicates that the intake
capacity of the kits, suckling only once a day, is limited because in the experiments of Szendrö et al.
(2002) kits that nursed in morning and evening by 2 different does had a 89% higher intake compared
to single nursed kits.
However, not only an increasing number of suckling kits favours milk yield but also an increasing
litter weight at birth increases milk production as consequence of the uterine induction. Vásquez
Martínez et al. (1999) studied the interaction between both factors using a complete kit exchange at
birth and standardized litter sizes of 7, 8 or 9 suckling kits (Figure 3). Does with low litter weight (<450
g) showed no increase in milk yield with increasing number of suckling kits. On the contrary, does
with medium and high litter weight at birth (>450 g) had a significant higher yield by assigning
additional kits. Due to the limited number of kits born or suckling kits in some non selected lines or
populations, maximum milk production can therefore not be reached as demonstrated by Bolet et al.
(1996). However, Zerroucki et al. (2005) demonstrate in a local population that maximum does milk
production capacity can be reached for a number of kits lower than the maximum litter size naturally
observed in this population: in theses author’s observations milk production increases regularly
with the suckling kits number until a maximum (7 in the present case) above which a plateau production
is observed whatever the kits number (7, 8 or 9).
Both for experimental purposes as under commercial field conditions, due to the common practise of
cross fostering between does littering on the same day, the effect of litter size on milk yield is
minimised. Nevertheless when comparing does milk production published in the literature, attention
must be paid to the number of kits to which the litter size was adjusted in each case.
Parity order
The milk yield of does has a curvilinear relationship with parity (Khalil, 1994) and increases until the
third lactation and stabilizes thereafter (Casado et al., 2006). McNitt and Lukefahr (1990) reported
even an increase till the 7th litter; however because less productive females were progressively culled
out, their selection policy has favoured the milk yield with increasing parity order.
Figure 3. Effect of number of assigned kits on the milk yield of does dependent of the initial litter weight at
birth (Vásquez Martínez et al., 1999).
Milk yield 0-21d
<450 450-600 >600
Initia l litte r birth weig ht (g)
Assigned kits
The highest difference is found between the 1st and 2nd lactation. Even at standardised litter size,
Xiccato et al. (2004) reported an increase of 10% and 8% of the milk yield during lactation 2 and 3,
respectively. Pascual et al. (1999b) found a much more modest increase between primiparous and
multiparous does, on average only 3.6%. This difference was more pronounced (6.3%) when using a
low energy diet. Based on the litter weight at 3 weeks, Vicente and Garcia-Ximénez (1992) report a
difference of 14% in favour of multiparous does. Maertens et al. (2006) determined a 19.9% higher
yield in lactation 2 compared to lactation 1 even after a correction for the difference in litter size. Part
of this great difference could be explained by the early first insemination (15-16 weeks) compared to
the aforementioned studies.
The milk production increase is a response to the higher live weight and feed intake capacity of
multiparous does (Pascual et al., 1999b; Xiccato et al., 2004). Parigi-Bini and Xiccato (1998) mentioned
an increase of the voluntary feed intake of 10-20% from the first to the 2nd lactation and 7-15% from
the 2nd to the 3rd lactation. Moreover, primarily primiparous does have to share the energy between
the demands for milk (and eventually concurrent pregnancy) with those for body accretion because
they have not yet reached their adult weight (Parigi-Bini and Xiccato, 1998).
Number of nipples
A majority of does has 8 to 10 productive teats with independent mammary gland, although there is
a variation between 6 and 12 (Szendrö and Holdas, 1984; Fleischhauer et al., 1985). Nevertheless in
lines selected for litter size, teats number was increased as a passive answer to selection, and females
with 10 nipples may become the most numerous: 37% to 51% in 2 selected lines vs 27% in the control
line (Rochambeau et al, 1988). Females with less than 8 teats have a significant lower milk yield than
those with 8 or more teats (Fleischhauer et al., 1985). However, in this study, females with 6 teats
were obtained after surgically removing of 2 mammary glands. In the same study, females having
more than 8 teats showed a slightly higher milk yield (+2.2%). Szendrö and Holdas (1984) as did not
found significant differences in weight gain of kits till 21days of age between does having 8, 9 or 10
productive teats, although the highest value was obtained for does with 10. However Rochambeau et
al. (1988) considering only litters with more than 10 kits born alive, i.e. with kits number exceeding
that of nipples, observed higher litter weaning weights (28 days) for does having 10 nipples compared
to 8 (+13.2%), which implies a higher milk production.
Later on, limited attention has been putted on this factor. Only Mohamed and Szendrö (1992) compared
females with 8 and 10 nipples and determined a 4.8% higher milk yield in does having 10 nipples.
According to the observations of Petersen et al. (1989), milk secretion is higher in the middle pairs of
teats than in pairs 1 and 4.
In the intensive rabbit meat production, pure breeds are still seldom used and replaced by specialised
strains or lines selected for a higher litter size and therefore indirectly for a higher milk yield (Garreau
et al., 2004). The populations originating these actual selected strains or lines belonged near
exclusively to breeds of medium size, as mainly the New Zealand White or/and Californian. Usually,
the females on commercial rabbit farms are obtained by crossbreeding of these strains or lines to gain
the heterosis effect. These females are named crossbreds or “commercial hybrids”.
Literature data comparing milk yield of different breeds are scarce. Lukefahr et al. (1983) demonstrated
that New Zealand White does are superior (+ 30%) to Californian does and that crossbred rabbits of
both breeds are superior than the pure breeds. However, in another study, the same team determined
a comparable milk production for the 4 breeds tested (Calfornian, New Zealand White, Palomino and
White Satin) (McNitt and Lukefahr, 1990), which indicate that the genetic background of the particular
populations is perhaps more important than the breed itself.
Vicente and Garcia-Ximénez (1992) found significant higher litter weights after the 2nd and 3rd lactation
week in 2 synthetic lines compared with purebred New Zealand White and Californian. Native breeds
as Giza White (Khalil, 1994) or Kabylian rabbit population (Zerrouki et al., 2005) have a modest yield
(average over the whole lactation period of 100 and 104 g/d, respectively) compared to the actual
production level of over 200 g/d for commercial parental does (Fortun-Lamothe and Sabater, 2003;
Xiccato et al., 2005; Casado et al., 2006). However, these native breeds have a low adult weight.
When their milk yield is expressed per kg LW, the difference with medium-size breeds or hybrids is
less pronounced (Table 1). Moreover, comparing milk yield between different experiments (and strains)
remains difficult because especially for these native breeds temperature conditions were not
favourable. Under favourable housing conditions, recent reported data of multiparous females of
hybrid dam lines demonstrate an average daily yield of 250-260 g during the 4-weeks lactation period
(Xiccato et al., 2005; Maertens et al., 2006).
Even in the same population a large individual variability has been observed. Fernández-Carmona et
al. (2004) used the records of 943 lactations of crossbreds from 2 lines selected for litter size (V x A)
and milk yield ranged between 46 and 306 g/d during the 28 days lactation period. Also Khalil et al.
(2004) obtained, using a large data set, a variation coefficient of 38% for milk yield (0-21 d). Moreover,
heritability of milk production is low and amounts only 0.14 (Lukefahr et al., 1996) or 0.18 (Khalil et
al., 2004) for the cumulative 1 to 21 days of lactation. However, under current field conditions, litters
are equalised at parturition and by consequence milk yield is much more homogeneous with the
exclusion of the initial litter size effect (Casado et al., 2006).
Finally, in a study using transgenic does (for obtaining the presence of human clotting factor VIII,
hFVIII in their milk) milk yield was not significantly different from non-transgenic does descending
from the same founder females (Rafay et al., 2004). However, as the authors pointed out, it is necessary
to verify these preliminary results on a larger set of animals before to generalize this observation for
all transgenic does.
High environmental temperatures have a detrimental effect on milk yield of does. Several studies
have clearly demonstrated that the effect of high temperature can be explained by the drop in feed
intake which is in the same range as the drop in milk yield (Rafai and Papp, 1984; Maertens and De
Groote, 1990; Pascual et al., 1996; Szendrö et al., 1999a).
Under constant ambient temperatures, Rafai and Papp (1984) found a decrease of 7.7 g/d with each
centigrade of temperature rise above 20°C. Moreover, the relative decrease is depending from the
lactation stage, being largest in the week with the highest yield (3rd week) (Rafai and Papp, 1984;
Pascual et al., 1996; Szendrö et al., 1999a). The detrimental effect of high temperature on milk yield
was also clearly observed by Fernández-Carmona et al. (2000). When housed in a climatic chamber at
30°C, milk yield dropped with 30-40% according to diet compared with housing under conventional
circumstances (Pascual et al., 2000b).
In the study of Szendrö et al. (1999a) the heat stress was not yet pronounced on milk yield when
housed at 23°C (Figure 4). However, at 30°C, average daily milk yield was reduced with 29% (114 g vs.
161 g/d).
Under natural housing conditions, with varying temperature between day and night, heat stress is
less pronounced and seems to be linked with the minimal temperature during the active feeding
period (Maertens & De Groote, 1990). However, when the minimum temperature was above 24°C total
lactation yield was reduced with 17.3% compared to conditions below 24°C (Pascual et al., 1996).
Rearing, feeding, body weight and body condition
The litter size in which does were raised in before weaning did not influence their later milk yield
(Rommers et al., 2001). However, it has been shown that the feeding regime during the rearing period
has an influence on the subsequent litter weight (milk yield) of primiparous does and even in
multiparous does. Primiparous does fed restrictively during rearing and ad libitum later had an
increased litter weight at 16 days (Rommers et al., 2004) or 21 days (Gyovai et al., 2004) compared to
always ad libitum fed young does. The significant increased feed intake during the subsequent
lactation observed in previously restricted reared does seems responsible for this effect in primiparous
does (Rommers et al., 2004). However, in the 2 following lactations an effect on the feed intake was
not more clear in this study indicating that some other factors could be involved, such as higher
body weight and/or appropriate body condition. Gyovai et al. (2004) observed higher body weight
(at 1st kindling and maintaining during the successive cycles) in does reared under feed restriction. In
contrast, Rommers et al. (2004) reported higher body weight in ad libitum reared does but their lower
milk yield fall essentially on the very heavy young does (>4,5 kg at first insemination at 17.5 weeks
of age), perhaps excessively fatty (Rommers, 2004). In earlier experiments, Coudert and Lebas (1985)
did not observe any significant effect of feed restriction during rearing on does LW measured 7 days
after the kindling in the 3 first lactations. Thus some factors other than rearing conditions seem to be
as well important for milk production or does body weight as the feed restriction itself.
Complementarily, in ad libitum reared does inseminated at early age (14.5 weeks), small young does
(<3.5 kg, averaging 3.18 kg at insemination) had significant lower litter weight at 16 days (milk yield)
than heavier, in their two first lactations (Rommers et al., 2002).
Milk yield (g)
Figure 4. Effect of temperature ( ) on milk yield of does (Szendrö et al., 1999a).
0 3 6 9 12 15 18 21 24 27 30
Days after kindling
Body weight of different dam lines did not have a significant effect on milk yield although their
weight differed by 10% at their first parturition (Fortun-Lamothe and Bolet, 1998). However, Pascual
et al. (2002a) observed that does presenting a better body condition at partum showed higher milk
yield. Perirenal fat thickness at parturition used as indicator for body condition revealed to be
positively correlated (r=+0.36) with the subsequent milk yield. However, the change of the body
condition during the lactation is negatively correlated with milk yield (r=0.24 and 0.61, Fortun-
Lamothe and Lebas, 1996 and Pascual et al., 2002a, respectively). This shows that does exhibiting
higher body-fat losses during the lactation have also a higher milk yield. This relation could be
reinforced or reduced according to diet’s composition as demonstrated by Pascual et al. (2003) in
their review.
Major components
The average chemical composition of rabbit milk is presented in Table 3 and Figure 5. In total 20
original publications were found with determined data of the macro nutrient composition from does
fed a standard diet. Data referring to experimental diets with high fat content were excluded from the
dataset used for this review. Literature data are grouped per lactation week.
The lactose content of doe milk was determined only in few experiments because of the minor
importance due the low content (<2 g/100 g) especially at a later stage of the lactation (Lebas, 1971).
Moreover, in several experiments the content was calculated by difference with the other nutrients.
As a result, the variation coefficient is high for lactose (Table 2).
There exists little information concerning the composition of the colostrum of does (Lebas, 1971; El-
Sayiad et al., 1994; Christ et al., 1996). Based on these data the colostrum DM is higher than milk DM
(33 vs. 30 g/100 g) due to a higher protein content and fat content. However, this composition has to
be taken with caution because the samples were collected on the day after kindling. The real colostrum
is already consumed by the kits during the initial suckling which takes place during the parturition
(Hudson et al., 2000).
Based on the overview of literature data (Figure 5), the composition of rabbit milk is quite stable
during the 2nd and 3rd week of the lactation, except for the protein content which shows a decreasing
trend (from 12.8 till 11.9 g/100 g) with increasing daily milk yield. This quite constant composition
during the 3 first weeks of the lactation (with exception of the first days) is remarkable because milk
yield increases in that period with a factor of 2 till 3.
Already in week 4, the DM content is on average 2.6 points (+ 8.7%) higher and the fat and protein
content increase by 1.1 g/100 g (+ 8-9 %) compared to the average of the first 3 weeks (Table 3). In
week 5, a strong concentration of the milk is observed which results in a DM, fat and energy content
of 36.9 g/100 g, 18.7 g/100 g and 10.5 MJ/kg, respectively. Ash and protein increase more slowly in the
final week of the lactation.
The changes in composition in the later stage of the lactation period are closely related with the
decrease in milk yield (Lebas, 1971; Partridge at al., 1986a). The dramatic reduction of the lactose
content is even higher than the corresponding drop in milk yield (Lebas, 1971). In does immediately
pregnant after parturition, dry matter, protein and fat increases one week earlier than in does not
concurrently pregnant (Kustos et al., 1996). An interruption of the lactation by omission of one
suckling leads to changes in milk composition similar to those observed with declining milk yield
(Szendrö et al., 1999b). However, some days later the composition returns to levels approaching the
original values.
Table 3: Che mic a l co mp o s it io n of rabbit milk dep e nding o f the lactatio n st a ge
Lactation week Mean Range CV(%) n1
Dry matter (g/100 g) Colostrum 32.6 31.4-33.7 5 2
1 29.8 25.6-31.4 9 5
2 30.0 25.7-33.1 9 9
3 29.5 25.8-33.2 7 19
4 32.4 29.8-33.7 5 6
5 37.7 34.2-42.1 7 6
Ash (g/100 g) Colostrum 1.8 1.7-2.0 18 2
1 1.9 1.8-2.0 6 3
2 1.9 1.3-2.2 16 7
3 2.2 1.5-2.6 13 13
4 2.4 1.8-2.6 15 5
5 2.4 2.0-2.8 12 5
Protein (g/100 g) Colostrum 14.7 13.5-15.9 12 2
1 12.8 11.2-14.8 11 6
2 12.2 10.1-14.1 10 11
4 13.4 10.6-15.5 12 7
5 14.1 12.4-16.9 11 6
Fat (g/100 g) Colostrum 16.3 13.7-20.4 22 3
3 12.9 10.0-16.6 16 19
4 14.0 12.2-15.7 11 5
5 18.9 16.9-21.4 9 6
Lactose (g/100 g) Colostrum 1.9 1.6-2.1 18 2
1 1.6 1.0-2.0 36 3
2 1.4 1.0-1.9 33 3
3 1.9 0.3-3.2 50 8
4 1.8 0.8-2.6 51 3
5 1.0 0.2-1.8 9 2
Energy (MJ/kg) Colostrum 9.3 - - 1
1 8.4 8.4-8.4 0.1 3
2 8.5 7.5-9.6 10 6
3 8.3 7.1-9.2 7 9
4 9.2 8.5-10.0 8 3
1n= number of literature references used to calculate the values in table.
References: Castellini et al. (2004), Christ et al. (1996), Cole et al. (1983), El-Sayiad et al. (1994), Fraga et al. (1989), Kowalska
and Bielanski (2004), Kustos et al. (1999), Lebas (1971), Lebas et al. (1996), Maertens et al. (1994, 2005 and 2006), Partridge
and Allan (1982), Partridge et al. (1983, 1986a and 1986b), Pascual et al. (1996, 1999a and 2000a) and Xiccato et al. (1999)
Figure 5. Milk composition changes during the lactation period (literature compilation, see Table 3).
Milk composition did not vary significantly between New Zealand White and Duch rabbits (Cowie,
1968) or between commercial hybrids (Maertens et al., 2006). However, El Sayiad et al, (1994) found
significant higher crude protein levels in Californian does (12.02 g/100 g) than in New Zealand
females (11.02 g/100 g) The effect of temperature or the feeding level seems not very outspoken.
Only at 30°C a trend to decreasing fat, protein and especially lactose content was observed (Kustos
et al., 1999).
In general, rabbit milk can be characterised as a very protein and fat rich milk (12.3 and 12.9 g/100 g,
respectively) but with low lactose content (1.7 g/100 g). Compared to cow and sow milk, rabbit milk
is respectively 2 and 3 times more concentrated in fat and protein (Table 5). The lactose content is
only one third of the 2 other species. Remarkable is also the high energy content of rabbit milk (8.4
MJ/kg) which explains the rapid growth of the kits (LW x 6 after 3 weeks).
At peak lactation, fat and protein output per kg LW are 3 to 4 times higher in rabbits compared with
cows and sows (Table 2). This explains why rabbits are searched as bioreactor for the production of
recombinant proteins. The fat production per kg metabolic weight at peak lactation equals (14.1 g/
kg0.75) that of high productive Holstein cows and exceeds that of hybrid sows (Table 2). The protein
production (13.4 g/kg0.75) exceeds largely those of both cows and sows.
Milk lipids
With an average lipid content of 12.9 g/100 g (Table 5), it is clear that the greatest energy source
quantitatively for the suckling kit is the fat component. The milk lipids are composed mainly of
triglycerides with small proportions of di- and monoglycerides, phospholipids, cholesterol, fat-soluble
vitamins and free fatty acids (Smith et al., 1968; Perret et al., 1977; Demarne et al., 1978; Christie,
1985). Triglycerides of acyl carbon number less than 42 made up about 75% of the total glycerides in
rabbit milk (Smith et al., 1968).
The fatty acid (FA) profile of rabbit milk is characterized by a very high content of short-chain FA,
mainly caprilic (C8:0), capric acid (C10:0) and, to a smaller extent, lauric acid (C12:0), which represent 50%
of the total FA (Table 4). Consequently, milk fat of rabbits differ very markedly from the carcass depot
fats. On average 70% of the milk FA are saturated (SFA), 13% monounsaturated (MUFA) and 16%
polyunsaturated FA (PUFA). Nevertheless it must be pointed out that in the suckling kit, the fate of
the saturated FA is very different according to the carbon chain length: short chained FA (70.0% of
saturated FA) are almost exclusively used as energy source (or basis for length elongation) and only
the longer ones are transferred in the body fat (Ouhayoun et al, 1985).
The milk contains nearly equal proportions of oleic and linoleic acid, and some ù-3 linolenic acid.
Concerning the longer w-3 FA searched for their potential as beneficial for health, small amounts of
C20:5,w-3 (EPA: 0.04%) and C22:6,w-3 (DHA: 0.06%) are mentioned by Castellini et al. (2004) and Kowalska
and Bielanski (2004). Moreover, these last authors found also a small amount of conjugated linoleic
acid (CLA) (0.08%). The proportions of these polyunsaturated FA are mainly dependent of the
lactation diet.
Fatty acids in milk are derived from blood triglycerides and de novo synthesis in the mammary gland.
Short-chain FA are synthesized within the mammary gland rather than by FA uptake from circulating
blood or by oxidation of long-chain FA (Carey and Dils, 1972). Acetate is an important precursor of
both C8:0 and C10:0 (Jones and Parker, 1978).
Diet has a very strong influence on the FA profile of rabbit milk especially on the medium and long-
chain FA (see the review of Pascual et al., 2003), but only little information exists concerning the non-
nutritional factors affecting FA composition. Perret et al. (1977) determined an increase of short
triglycerides (C<36) at the expense of long triglycerides (C>46) after the 10th day of lactation and the
same effect but less pronounced for FA (Hall, 1971). Significant changes of the FA profile during the
lactation stage were confirmed by Pascual et al. (1999a). Short-chain FA and by consequence SFA
showed a significant increase at the 21st and 28th day. The trend for medium-chain FA was opposite,
showing the highest proportions on day 7 of the lactation except for C15:0 and C17:0 that remained
constant during lactation (Pascual et al., 1999a; Christ et al., 1996).
The FA profile of rabbit milk is strikingly different from cow and sow milk (Table 5). Data refer to a
standard feeding of these species because especially fat-enriched diets manipulate to a large extend
the FA profile (Pascual at al., 2003). The high concentration of short-chain FA (C6:0 to C12:0) results in
a more saturated milk compared to especially sow milk. On the contrary, medium-chain FA (C14:0 to
C17:1) are nearly three times as high in cow and sow milk. Due to the low content of C18:1, rabbit milk
has a rather low MUFA content MUFA (12.8%) compared to cows (30.1%) and sows (41.5%). The
PUFA content is comparable with sows and much higher than in cow milk. The ratio w-6/w-3 FA
(around 4) is intermediate between sows and cow milk.
The FA profile is also remarkable different from the hare or rodents fed the same diet. The concentration
of short-chain FA are 2.1 times lower in hare milk compared to rabbit milk (Demarne et al., 1978).
Short-chain FA are even absent in guinea pig milk, and to a much lesser extent are present in mouse
(one third of rabbit) or rat milk (half of rabbit) (Smith et al., 1968).
Rabbits are known for their sensitivity to dietary-induced hypercholesterolemia but their milk
cholesterol levels can be normally maintained unless the maternal plasma cholesterol concentration
is extremely elevated (Whatley et al., 1981). Milk cholesterol concentration increases from 28.0 (day
5) till 89.7 mg/100 ml (day 35 of the lactation) in close correlation with the milk triglycerides and
drying up of the females (Whatley et al., 1981). In the mammary gland the cholesterol excretion in
milk is regulated but without local synthesis: nearly all the milk cholesterol derived from the blood
plasma cholesterol (Connor and Lin, 1967).
Milk protein composition
Rabbit milk proteins have been studied intensively in view of biomedical research for e.g. the production
of recombinant proteins in the milk or serum. A recent successfully example is the human a-glucosidase
produced in the milk of transgenic rabbits to treat the Pompe´s disease (Van den Hout et al., 2001).
However, in this review the information will be limited to the composition of the main constituents,
referring for specific information to other reviews (Fan and Watanabe, 2003; Bõsze and Houdebine,
Table 4: Fatty acid comp o s itio n of rabbit milk.
Fatty acids (% of total fatty acids)
Mean CV(%) n1
C4:0; C5:0; C7:0 Traces - 1
C6:0 0.4 20 3
C8:0 26.3 27 6
C10:0 20.1 21 6
C12:0 2.9 30 5
C14:0 1.6 39 6
C15:0 0.8 79 3
C16:0 12.8 23 6
C17:0 0.7 55 3
C18:0 2.9 11 6
C20:0; C22:0 Traces - 2
Total saturated fatty acids (%) 70.4 14 7
C14:1;C17:1; C20:1 Traces - 2
C16:1 1.5 59 6
C18:1 11.3 18 6
Total monounsaturated fatty acids (%) 12.8 17.6 7
C18:2 12.8 37 7
C18:3 2.5 36 7
CLA 0.08 - 1
C20:4 0.5 49 2
EPA (C20:5 w-3) 0.04 47 2
DHA (C22:6 w-3) 0.06 64 2
Total polyunsaturated fatty acids (%) 15.6 35 7
1n= number of literature references used to calculate the values in table.
References: Caste llini et al. (2004), Christ et al. (1996), Fraga et al. (1989), Kowalska and Bielanski (2004), Lebas
et al. (1996), Maertens et al. (2005), Pascual et al. (1999a).
The protein-rich milk of rabbits provides primarily the amino acids essential for tissue growth and
maintenance but also to continue a certain degree of immune protection through the presence of
specific whey proteins. Information concerning the amino acids composition is given in Table 6.
However, the data of rabbit milk have to be taken with caution because the total sum of amino acids
expressed per 100 g amino acids is 118.6 g (recalculated data from Uribe et al., 1980) or only 76.9 g
(Kustos et al., 1999).
Rabbit milk proteins as for other mammals, are grouped in two main types: caseins which precipitate
in the isoelectric conditions (pH 4.6) and represent about 70% of the total milk proteins and whey
proteins which do not precipitated in these conditions (Dayal et al, 1982). After numerous attempts
to identify the various types of casein present in rabbit milk (Allais and Jollès, 1970; Majumder and
Ganguli, 1970; Testud and Ribadeau-Dumas, 1973; Al Sarraj et al., 1978; Dayal et al., 1982; Baranyi et
al., 1995; Grabowski et al, 1991, Virag et al., 1996), 4 types can be clearly distinguished now: aS1-
casein, aS2-casein, a-casein and k-casein. Total of caseins represent about 90 g/l with a specific
contribution for example of 45 g/l of b-casein and 16 g/l of aS1-casein (Grabowski et al, 1991). Virag et
Table 5: Comparative composition of milk from rabbits, cows and sows.
Rabbit does1Cows2Sows3
Dry matter (g/100 g) 29.8 12.5 - 13.5 17.9
Protein (g/100 g) 12.3 3.0 - 4.0 5.1
Fat (g/100 g) 12.9 3.5 - 5.0 6.5
Lactose (g/100 g) 1.7 4.5 - 5.0 5.7
Energy (MJ/kg) 8.4 2.7- 3.2 4.5
Fatty acids (% of total FA) C6:0 0.4 1.5 n.r.
C8:0 26.3 0.9 n.r.
C10:0 20.1 2.0 0.4
C12:0 2.9 2.4 0.5
C14:0 1.6 14.3 5.6
C16:0 12.8 24.4 29.4
C16:1 1.5 1.7 13.7
C18:0 2.9 11.9 6.3
C18:1 11.3 27.5 27.6
C18:2 12.8 1.6 13.3
CLA 0.08 1.26 n.r.
C18:3 2.5 0.71 1.4
C20:1 n.r.4n.r. 0.2
C20:4 0.5 0.04 0.09
C20:5 (EPA) 0.04 0.01 0.16
C22:6 (DHA) 0.06 0.04 0.20
Other 4.2 6.3 1.2
Total SFA 70.4 60.0 42.2
Total MUFA 12.8 30.1 41.5
Total PUFA 15.6 3.6 16.3
Ratio w-6/w-3 4.1 2-3 7.2
1Average composition of lactation weeks 1-3 (Table 2). 2
FA adapted from Rego et al. 2005 (Control diet, pasture). 3
and Danielsen, 2004 (Control diet). 4Not reported.
al. (1996) mentioned a micelles size of skimmed rabbit milk varying from 210 to 230 mm in relation with
the 8 patterns of aS2-caseins observed in the milk of New Zealand White does. One of the functions
of the k-casein is the formation, stabilisation and aggregation of the micelles (Gerencsér et al, 2002).
In addition some hydrolysed fractions of aS1 and b-casein have a clear antibacterial activity which
most probably participate in the protection of digestive tract of suckling kits (Baranyi et al., 2003).
The main types of whey proteins are a-lactalbumin, tranferrin, serum albumin, whey acidic protein
(WAP) and immunoglobulins (Baranyi et al; 1995). Transferrin is present at 17 to 23 g/l (Jordan and
Morgan, 1970) and is an iron binding protein identical to the serum transferrin (Baker et al., 1968)
which has no immunological reaction with the classical lactoferrin (Lyster, 1967). This specificity
explains for example why Masson and Hermann (1971) failed to find lactoferrin in the rabbit milk in an
extensive study of lactoferrin in different species conducted with an immuno-methodology. Despite
its identity with serum transferrin, the milk transferrin is almost exclusively synthesised and secreted
in the mammary gland (Jordan and Morgan, 1970). This protein has an in vitro antibacterial activity
against Escherichia coli, but it is not clear if this function is still active in vivo in the kits digestive
tract (Baker et al., 1968).
As previously mentioned, other whey main proteins detected in rabbit milk are serum albumins (4-5
g/l), different lactalbumins, WAP (15 g/l) (Jordan and Morgan, 1970; Grabowski et al, 1991; Baranyi
et al., 1995) and different immunoglobulins but no protein resembling to the cow b-lactoglobulin (the
main whey protein in cow milk) was detected (Lyster, 1967). Nevertheless this affirmation disagrees
with the results of Stambolova and Gachev (1972) which have identified a rabbit whey protein with an
electrophoretic pattern identical to that of the bovine b-lactoglobulin.
The g-globulin concentration is around 10 g/l and increases in milk during lactation (Jordan and
Morgan, 1970; Maertens et al., 1994). According to Berthon and Salmon (1993), the specific
immunoglobulins concentration decreases from colostrum to milk. They are represented mainly by
the IgG form, which represents 95.2% of the total immunoglobulins of colostrum (30 g/l) and 98% of
milk ones (5 g/l). The IgA represent a higher proportion in colostrum (4.7%) than in milk (2.0%). In
addition the presence of few IgM can be noticed in colostrum (0.1% of the total) but only traces are
present in milk. During g-globulin secretion in the mammary gland, the initial serum IgA is modified
and T-Chains are added (Asofsky and Small, 1967). The immunoglobulins present in the first suckled
colostrum seem to be transferred to the kit serum (Goszinska et al, 1969). But later, absorption
Table 6: Amino acid compo sition o f rab b it a nd sow milk .
Amino acid
g/100 g amino acid
Amino acid
g/100 g amino acid
Lysine 9.0-7.6 7.5 Valine 8.0-5.9 4.7
Methionine 3.0-1.6 1.7 Tryptophan 1.3 -3 1.4
Cysteine -31.5 Arginine 6.4- 4. 8 5.2
His tidine 5.3 - 2.3 2.4 Proline 3. 2 - 3 11.3
Phenylalanine 4.9-3.3 3.9 Glycine 1.5-3.7 2.8
Tyrosine 6.2-2.6 4.2 Glutamic acid 25.0-12.7 21.6
Threonine 7.3-4.1 3.9 Aspartic acid 8.1-4.0 7.9
Isoleucine 4.2-3.6 3.8 Serine 5.6-6.1 5.2
Leucine 11.9-8.9 8.8 Alanine 7.7-5.7 3.2
1Left values from Uribe et al. (1980); right values from Kustos et al. (1999). 2
Acc ording to Dar ra gh and M oughan (19 98). 3Traces
for Ur ibe et al. (1980) and not determined by Kustos et al. (1999).
throught the intestinal epithelial cells of the kits in direction of blood is generally stopped inside the
enterocytes (Krahenbuhl and Campiche, 1969).
The immunisation of does against specific agents such as E. coli or Vibrio cholerae induce the
presence of specific IgA antibodies in the milk during the whole lactation (Yoshiyama and Brown,
1987; Milon and Camguilhem, 1989). These IgA can be immediately locally active in the kit digestive
tract. But their short half-life (3 days) makes them ineffective after weaning (Milon and Camguilhem,
Also prolactin and growth hormone binding proteins have been identified in rabbit milk (Postel-
Vinay et al., 1991) as well as thyroid hormones (Slebodzinski and Gawecka, 1983). In addition a lot of
active enzymes are detectable in rabbit milk (Hellung-Larsen, 1968).
Mineral content
The ash content of rabbit milk (Table 3) increases from about 1.8% during the first weeks of the
lactation till 2.4% in the 4th and 5th week of the lactation. This increase can partly be ascribed to the
drying up of the does and as consequence of the higher dry matter content with declining milk yield.
Rabbit milk is rich in calcium although its concentration varies according to the source (Table 7).
Also sodium and potassium concentration is high compared to sow milk (Darragh and Moughan,
1998). Since lactose and sodium are two of the main constituents concerned in maintaining the
constancy of the osmotic properties of milk it is not surprising that the low level of lactose in rabbit
milk is compensated by a sodium concentration higher than in cow milk (Coates et al., 1964). The
reduction of milk lactose concentration observed after the lactation peak is clearly associated with a
decrease of sodium and a correlative increase of potassium content because of the osmolarity
regulation (Gachev, 1971a)
As for the major components, mineral composition changes substantially after lactation peak
especially when does are concurrently pregnant and a very rapid drying up of their milk yield occurs.
Calcium concentration and to a lesser extend phosphorus increase with progressing lactation stage
(Lebas et al., 1971; Perret et al. 1977; Kustos et al., 1996) while the effect for potassium and sodium
is less clear. Potassium concentration drops dramatically with decreasing milk yield according to
Kustos et al. (1996) but this was not very outspoken in earlier work of Lebas (1971), Gachev (1971a)
and El-Sayid et al. (1994). El Sayid et al. (1994) reported a gradual increase of the sodium content
Table 7: Mineral compo sition (g/kg milk) of ra b b it milk 1.
Lebas et al.
Perret et al.
El-Sayid et al.
Kustos et al.
Kustos et al.
Sodium 1.03 0.82 1.16 0.84
Potassium 1.981.771.682.01
Calcium 5.36 3.64 4.82 2.76 2.71
Magnesium 0.35 0.36 0.45
Phosphorus 3.28 2.61 2.44
Chlorine 0.66
Zinc 0.02 0.021 0.034
Iron 0.003 0.003
Copper 0.002 0.002
Manganese 0.0001 0.0002
1Average value determined during lactation (colostrum excluded).
while Lebas et al. (1971) and Kustos et al. (1996) mention a tendency to a higher content at the
beginning and near the end of the lactation period. Magnesium content increases with lactation
stage (Lebas et al., 1971; Kustos et al., 1999) while the microelements (zinc, copper, iron and
manganese) decrease gradually in concentration as lactation progressed (Kustos et al., 1996 and
1999). For example, Tarvydas et al. (1968) observed a reduction of iron content from 3.9-4.6 mg/l 3-4
days after kindling down to 2.3 mg/l on day 17.
Phosphorus concentration decreases in pregnant does at the end of the lactation period probably
due to more phosphorus being derived to foetal growth (El-Sayid et al., 1994; Kustos et al., 1996).
However, the pregnancy effect was much less clear in the work of El-Sayid et al., (1994), because
females were not remated immediately after parturition. Calvert et al. (1985) observed a rise in milk
sodium and chlorine concentration and a decline in potassium and lactose during the milk accumulation
24 h after the last nursing.
Vitamin content
Few data can be found about the vitamin content of rabbit milk. The research done by Coates et al.
(1964) can therefore still be considered as basic information although only 1 or 2 samples per lactation
day were analysed. Rabbit milk is richer than cow milk in all the water-soluble vitamins and vitamin A
(Coates et al., 1964). The high level of vitamin A in the colostrum (6-7 mg/ml) was confirmed by El-
Sayiad et al. (1994) and also the gradually decreasing levels as the lactation proceeds. This fits with
the function of retinol being important for the kit eye development. Basic level of vitamin D3 is fairly
low in milk (0.6 mg/l or 24 IU/l), but very sensitive to doe circulating vitamin D3 level, since a single
injection of a massive vitamin D3 dose increases the milk vitamin D3 for minimum 5 days (Hidiroglou
and Williams , 1985)
The following levels for biotin (0.45 mg/ml), folic acid (0.30 mg/ml), niacin (4.9 mg/ml), pantothenic acid
(14.5 mg/ml), riboflavin (4.6 mg/ml), thiamin (1.6 mg/ml), pyridoxine (B6) (3.6 mg/ml) and B12 (0.07 mg/ml)
were determined on the 18th day of the lactation (Coates et al., 1964). However, some effects of stage
of lactation were observed e.g. an increase for biotin between 1st and 40th day of lactation (multiplied
by 2.7), and simultaneously a decrease of pyridoxine (divided by 6) (Gogeliya, 1970). More recently,
Cole et al. (1983) determined comparable levels for folic acid and vitamin B12 as the aforementioned
Some other components
It has been shown that rabbit milk has antibacterial effects (Canas-Rodriguez and Smith, 1966;
Marounek et al., 2002). When rabbit milk is added in cultures of rabbit caecal contents, a significantly
decreased production of microbial metabolites was determined, whereas no inhibitory effect of a
corresponding mixture of cow milk fat, casein and lactose was observed (Marounek et al., 1999).
The bactericidal effect is linked to the short-chain FA (C8:0 and C10:0) which make that suckling rabbits
are unique amongst other species in the contents of the stomach and small intestine that are almost
completely sterile. This is a natural protection against the risks of the very high milk intake in only
one meal a day. In rabbit milk triglycerides, C8:0 and C10:0 are mainly in the external position on the
glycerol molecule while C16:0 is mainly in the central position (Demarne et al., 1978; Christie, 1985).
This explains the quickly hydrolysis in the stomach which enables their antibacterial role in this gut
segment. In addition and as shown in the protein section, some proteic milk components have their
own anti-bacterial activity such as aS1 and b-casein fractions or transferrin, in addition to the classical
immunoglobulins activity. However, rabbit milk contains only few orotic acid (0.5 mg/l, compared to
the 18 mg/l of cow milk; Gajos and Krêzlewicz, 1974), a residue of arginine catabolism sometimes used
in human medicine in diarrhoea control.
Finally, rabbit milk can contain undesirable components transferred from contaminated diets or
treatments. For example an effective transfer of ochratoxin A from plasma to milk has been
demonstrated (Galtier et al., 1977; Ferrufino-Guardia et al., 2000). Also antibiotic residues are found
in milk as has been demonstrated after a tilmicosin treatment of does (Saggiorato et al., 2004).
Due to the time consuming determination of the milk yield and the divergent methodology used,
published data concerning the production capacities of does are quite scarce and difficult to be
compared. However, the production level of actual highly efficient hybrids used for commercial
rabbit production can be situated around 250 g/d (or 60 g/d/kg LW). By consequence, during a 30
days lactation period, total milk yield exceeds 7 kg in multiparous does.
There are much more data available of the macro nutrient composition of rabbit milk. Both the macro
composition as the fatty acid composition is widely different from cow or sow milk. Due to the high
yield of does and their concentrated milk, at peak lactation protein output per kg LW and even per
kg0.75 exceeds those of Holstein cows.
Rabbit milk distinguishes from other milks by its extremely high content of short chain FA. Their
antibacterial effects in the gut protect the kits against enteritis risks which are high due to the natural
suckling behaviour (only one daily quantitatively rich meal).
The non-nutritional factors having the largest impact on the milk yield are the lactation stage, the
number of suckling kits, the gestation overlapping degree (rapid decline after 17-20 days of gestation),
the parity order and heat stress (through feed intake depression for the later factor). However, due to
the common practise of equalizing the litter size at parturition, commercial strains are capable to
express their maximal yield aptitude.
Milk production has had little attention in selection programs in spite of its large importance in kit
survival and post-weaning growth.
Acknowledgment: The authors are very grateful to Andre Vermeulen for the help with literature search and data
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... Diante disso, a composição própria do leite da coelha é de suma importância para o ótimo desenvolvimento dos láparos, possuindo algumas particularidades nutricionais em relação ao leite de outros mamíferos domésticos, como é o caso do leite bovino, sendo o leite das coelhas 2,9 vezes mais concentrado em energia . Segundo Maertens et al. (2006), o leite das coelhas, quando comparado com o leite de porcas ou vacas, se mostra 2 a 3 vezes mais concentrado em gordura e proteína; porém, o seu conteúdo de lactose é de apenas um terço em relação ao desses animais. Além disso, os autores afirmam que, no pico de lactação desses três animais, a produção de gordura e proteína do leite da coelha, em relação ao kg de peso vivo, é 3 a 4 vezes maior do que aquela relacionada a bovinos e suínos, sendo o kg de peso metabólico semelhante ao de uma vaca holandesa de alta produção. ...
... Além disso, os autores afirmam que, no pico de lactação desses três animais, a produção de gordura e proteína do leite da coelha, em relação ao kg de peso vivo, é 3 a 4 vezes maior do que aquela relacionada a bovinos e suínos, sendo o kg de peso metabólico semelhante ao de uma vaca holandesa de alta produção. Em geral, o leite da coelha é rico em gordura e proteína e pobre em lactose (Tabela 1), o que garante rápido crescimento e desenvolvimento dos láparos (Maertens et al., 2006;Leite et al., 2022). Tabela 1. Composição química do leite da coelha (fêmea híbrida, com 4,2 kg de peso vivo). ...
... São poucos os trabalhos que estudam a composição do leite da coelha, pois diferentemente de outros mamíferos, em relação às coelhas, há grande dificuldade na coleta desse leite para a realização de análises químicas. Contudo, há alguns métodos para tal finalidade, como máquinas de ordenha (Marcus et al., 1990), indução pelo hormônio da ocitocina com método manual de coleta e também a coleta diretamente do estômago do láparo, sendo realizada via oral (de Blas et al., 1995;Maertens et al., 2006). Leite et al. (2022) desenvolveram um método para coleta de leite de coelha em que separaram a fêmea durante 24 horas dos filhotes e aplicaram duas doses de ocitocina com intervalos de 10 minutos entre elas, sendo a primeira dose 0,01 mL/kg de peso vivo e a segunda dose 0,005 mL/kg de peso vivo. ...
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Esta revisão objetivou levantar informações sobre o aleitamento artificial, abordando os tipos de sucedâneos mais aproveitados pelos produtores e também as estratégias utilizadas com o auxílio do aquecimento suplementar nos ninhos para reduzir a mortalidade dos láparos no período pré-desmame. Atualmente, a cunicultura tem seguido majoritariamente dois caminhos distintos, a produção voltada para carne e a criação de coelhos como animais de companhia, os denominados coelhos pets, e ambas necessitam de um programa de reprodução bem estabelecido para que se tenham láparos para comercialização. Todavia, o período do nascimento até o desmame compreende a fase mais crítica e que mais acomete os filhotes durante seu período na granja, estando isso associado a diversas causas e fatores. O aleitamento artificial é pouco utilizado na cunicultura, principalmente por não haver ainda, no Brasil, um sucedâneo específico para o coelho, que, em conjunto com o aquecimento suplementar dos ninhos, poderia representar uma importante estratégia para redução da mortalidade pré-desmama desse animal.
... Therefore, the change in doe's weight before and after suckling corresponds to the daily milk production weight. This method was described in the review of Maertens et al. (2006) as the optimal estimation of milk production (Tables 3 and 4). Samples of milk were first collected one day before lactation peak (MB+16), at lactation peak (MB+17) and one day after lactation peak (MB+18). ...
... This was due to milk and feed. According to Maertens et al. (2006), there is an increase of the daily feed intake of young rabbits starting between 18 and 19 days during the suckling period. ...
... However, Maertens et al. (2006) reported that the number of suckling kits is the main factor affecting milk yield but if the litter weight is less than 450 g, as it is the case in the present study, there is no increase in milk yield when the number of kits increases. ...
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Rabbit production is increasing in developing countries and can play a crucial role in the fight against poverty. The current work assessed the effect on rabbit does’ reproduction and young kits’ growth when either Panicum maximum, common name Guinea grass, or Desmodium tortuosum, common name Beggarweed is included in their diet. Diets ReC and GrC (standard granulated diets) served as control diets, formulated for doe Reproduction and kit Growth respectively. The trial diets were diets RePan/GrPan (diet ReC/GrC supplemented with dry Panicum maximum) and diets ReDes/GrDes (diet ReC/GrC supplemented with dry Desmodium tortuosum). Thirty-six primiparous local breed five-month old rabbit does were randomly allocated to each one of the three dietary treatments. After a 15-day dietary adaptation period, does were each bred to one of 12, related, breeding males. Does were then assigned to individual maternity cages maintaining the same dietary treatment for the ensuing 65 days of the trial (30 days of gestation + 35 days of suckling). Thus, there was a total of 12 replicates per treatment: diet ReC, diet RePan or diet ReDes. At weaning, seventy-two kits, from the three adult feed treatment groups, were, while maintaining the integrity of the feed group of their individual mothers, divided to twelve blocks with six weaned kits per block, with each block allocated one of the three diets. Thus, for each of the three diets there were four separate blocks, i.e. four replicates, each with six group-housed weaned kits that received a growth diet which contained the same supplement or not as their mother diet to which they had access prior to weaning; the control diet GrC (Composition slightly different from Diet ReC composition) and trial diets GrPan and GrDes over a 3-day transition phase were adapted to the weaned kits physiological state and fed for a total of 56 days. The results indicated that the use of Desmodium tortuosum significantly improved (P < 0.05) litter size, milk quantity, and kit survival rate from birth to weaning as compared with both control and RePan diets. The study showed that after weaning, compared with control and GrPan diets, the use of Desmodium tortuosum increased (P < 0.05) the growth performance of weaned kits, improved meat nutritional quality by reducing (P < 0.05) cholesterol concentration and increasing (P < 0.05) the n-3 fatty acid proportion, and also reduced the individual kit feed cost to slaughter weight.
... The doe was then only brought to the nest in the morning for 15-20 minutes to suckle the kits. 38,39 Milk yield was estimated once every week by the difference in the doe weight before and after suckling. This methodallows the accurate milk yield determination than the difference of kit weight to avoid the urination of its kits during suckling according to. ...
... This methodallows the accurate milk yield determination than the difference of kit weight to avoid the urination of its kits during suckling according to. 39,40 The total milk yield during lactation was estimated by multiplying the average daily milk yield during lactation by 28 days. The total feed intake during lactation/total milk yield per lactation ratio was calculated according to. ...
... From this study, we found that milk components in terms of fat, protein and lactose were affected by adding turmeric, MOS and Biostrong to rabbit diets during pregnancy and lactation. The percentage of fat and lactose in the milk components increased, especially in the mixed groups between turmeric and MOS or between MOS and Bostrong, and the protein of the milk components decreased in all treatments this result agreement with Maertens et al. (2006) who reported that the protein content gradu-ally decreased during the lactation weeks with increasing daily milk yield. Rabbits in group 5, especially in the third parity recorded high milk yield, this increase may be due to the interactive effect of turmeric and MOS to stimulate milk production while reducing oxidative stress caused by high temperature or physiological processes of rabbits, and it was evident in the third parity over the second and the first, to highlight the cumulative effect of additives. ...
... The level of milk production defines the growth of kits during the nursing period, thus affecting their later performance (Maertens et al., 2006). According to the literature, the milk yield increases from 50 g on the day of birth to 240 g on the 21st day of lactation and decreases after reaching this lactation peak. ...
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This study aimed to examine the effect of mastitis incidence on the litter size, litter birth weight, and milk composition of Hycole does on a commercial rabbit farm during their third and fourth parity. At third parity does were assigned to the “No mastitis” (n = 30) and “Mastitis” (n = 28) groups on the basis of visible abscesses in the mammary gland area. The microbiological analysis revealed the presence of different pathogenic bacteria. At third parity, “Mastitis” females had fewer kits than the “No mastitis” group, and the average birth weight was lower. On day 2 of the third lactation, “Mastitis” does produced significantly less milk daily compared with the “No mastitis” group. A significant effect on the incidence of mastitis on the litter size and litter weight during the growth of kits up to the 35th day was also observed. The effect of the incidence of mastitis on milk chemical composition was limited. At the fourth parity, the litter characteristics and daily milk yield were leveled in “Mastitis” and “No mastitis” females. To conclude, our study showed that mastitis negatively affects litter size, birth weight, and daily milk yield in the current parity. However, early detection and proper treatment allowed to obtain good reproductive results and healthy kits in the next parity.
... Later on, Lukefahr (1990) Genotype of doe tended (P > 0.07) to be important for milk yield; Californian does had higher production than does of other breeds Schlolaut (1998) In Angora rabbits, the longer the hair grows, the less feed they ingest and the milk yield is lowered El Nagar et al. (2014) Differences among three Spanish maternal lines (A, V, LP) Ludwiczak et al. (2020) Does of large and heavy breeds produce more milk than those of small, light breeds Week of lactation Schley (1985) Milk yield of the doe increases to around 100-150 g per day in the first 2 weeks of life of the kits. It doubles by the third week, reaching its peak (up to 300 g) between the 18th and 23rd day after the birth of the kits Maertens et al. (2006) In multiparous does subjected to intensive reproduction rhythms (mating within 3 days after parturition), the milk output peaks 2-3 days earlier Lebas et al. (1972) From the 22nd day postpartum, and especially after the 28th day of lactation, the milk yield of pregnant does decreased very rapidly Lebas et al. (1972), Xiccato et al. (1995 The intensive reproduction rhythm (mating the does within 3 days postpartum) decreases the production of milk even after 17-19 days of lactation. A semi-intensive reproduction rhythm (mating on postpartum day 11) allows them to maintain high production of milk even after 25 days Seitz (1997) Individual milk intake of kits per suckling event increases up to the 2nd week of lactation and decreases until the 4th week El Nagar et al. (2014) Milk output: grams/week Line ...
Direct care of offspring by the father (sire) is relatively rare in primates. Besides humans, there are a number of species where the male is essential for the survival of offspring: marmosets, tamarins, titis and owl monkeys, some lemurs, and siamangs. All these species show reduced sexual dimorphism, territoriality, and biparental care. However, timing and levels of direct care may vary among these species. Here, relying on both lab and field data, we address the variability found in father's involvement with his infants, the behavioral, neuroendocrine and sensory systems that are a cause and consequence of paternal care, and social bonds between the breeding pair. We integrate studies of laboratory animals (where detailed observations and experimentation are possible) with field studies (which illuminate the ecological and evolutionary functions of paternal care) and discuss the future directions for examining the proximate and ultimate mechanisms of paternal care in nonhuman primates.
We explored a possible role of oxytocin (OXT) for the onset and maintenance of rabbit maternal behavior by: a) confirming that a selective oxytocin receptor antagonist (OTA) widely used in rodents selectively binds to OXT receptors (OXTR) in the rabbit brain and b) determining the effect of daily intracerebroventricular (icv) injections of OTA to primiparous and multiparous does from gestation day 29 to lactation day 3. OTA efficiently displaced the high affinity, selective oxytocin receptor (OXTR) radioligand, 125I‐labeled ornithine vasotocin analog (125I‐OVTA), but was much less effective at displacing the selective V1a vasopressin receptor radioligand, 125I‐labeled linear vasopressin, thus showing high affinity and selectivity of OTA for rabbit OXTR as in rodents. Further, ICV OTA injections did not modify nest‐building, latency to enter the nest box, time spent nursing or the amount of milk produced, relative to vehicle‐injected does. The percentage of mothers suckling the litter was also similar between both groups, regardless of parity. Together, our results do not support a role of OXT for the initiation or maintenance of rabbit maternal behavior. Future studies are warranted to determine if OXT participates in fine‐tuning additional aspects of the maternal ethogram, e.g., circadian periodicity of nursing and nest defense.
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Cet article présente une synthèse bibliographique sur la cuniculture en Afrique subsaharienne et les valeurs nutritionnelles de la viande de lapin. La cuniculture constitue l’une des alternatives exploitées par les pays de l’Afrique subsaharienne pour réduire l’insécurité alimentaire grandissante. La viande maigre de lapin possède un taux élevé de acides gras insaturés et faible en cholestérol, une richesse en protéines de haute valeur biologique, en potassium, phosphore et magnésium. Pour des lapins aux âges et poids commerciaux d’abattage, les teneurs en protéines, eau et minéraux totaux sont respectivement de 21 %, 72,5 et 1,2 % de viande fraîche. La viande de lapin est pauvre en sodium, mais riche en phosphore. La viande de lapin montre un profil global en vitamines proche de celui du poulet. Par ailleurs, cette viande présente un ratio en acides gras oméga 6 / oméga 3 avantageux de 5,9. Du point de vue sensoriel, la viande de lapin appartient aux viandes "blanches". Elle est parmi les plus tendre mais sa jutosité est parfois limitée. Sur le plan zootechnique, le poids moyen d’un lapereau à 28 jours d’âge est de 396±132 g. Le poids moyen par lapereau sevré varie entre 483 g et 650g à 35 jours d’âge type. Le gain moyen quotidien varie de 17,95 g à 28,5 g/j. Le poids moyen des lapins en engraissement pour une durée de 56 jours varie de 1,92 kg à 2 kg. Les lapins de race commune élevés au Bénin ont une moyenne de 5 à 6 portées par an. Le taux de fertilité varie entre 50% et 95%. La taille de la portée à la mise-bas varie de 5,7 à 6,6 lapereaux nés totaux. Au sevrage, la taille moyenne varie de 4,8 à 5,7 lapereaux par portée née.
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Objective: The primary objective of this study was to investigate how varied levels of Amino Acid-rich Composite Sweet potato affected lactating performance and overall Reproductive Cycle Outcomes in does. Materials and Methods: The crude protein content and amino acid profile of leaf, roots and composite meal produced from 65% root and 35% leaves for two varieties of sweet potato (Ipomoea batatas Lam.) namely, TIS 87/0087 white flesh sweet potato (WFSP) and CIP 440293 orange flesh sweet potato (OFSP), were analyzed. Twenty-five rabbit does of mixed breeds (New Zealand White×California×Chinchilla) aged 6-7 months were assigned randomly to one of five experimental diets: T1 (control), T2 and T3 contained 25 and 50% orange-fleshed CSPM and T4 and T5 contained 25 and 50% white-fleshed CSPM. The diets comprised 10.6-12.6% crude fibre, 16.4-17.6% crude protein and metabolizable energy of 2610-2788 kcal kgG1. Results: The crude protein content in roots of 87/0087 (WFSP) and CIP 440293 (OFSP) were 3.32 and 8.04%, respectively. There was an appreciable higher value of crude protein in the leaf of TIS 87/0087 (11.18%) and CIP 440293 (11.26%), respectively. The crude protein content was least in composite WFSP (6.13%) and higher in composite OFSP (14.8 %). Total amino acid content ranged from 7.704 to 18.35 and 23.717 to 23.863 g/100 g protein for root and leaf samples, respectively. The overall feed intake of does in all the treatments was not significantly different (p>0.05). Does fed on diets T4 and T5 had the largest litter size at birth (5.00) compared to the other treatments. In different treatments, there was no significant difference in initial average body weight, gestation duration, or litter weight of does at birth. Conclusion: The high content of crude protein and its quality amino acids in the two varieties of the sweet potato composite meals placed it on a commensurate level for consideration as a potential replacement for expensive conventional protein sources in livestock diets.
Rabbit maternal behavior (MB) impacts meat and fur production on the farm, survival of the species in the wild, and pet welfare. Specific characteristics of rabbit MB (i.e., three-step nest building process; single, brief, daily nursing bout) have been used as models for exploring particular themes in neuroscience, like obsessive-compulsive actions, circadian rhythms, and cognition. Particular hormonal combinations regulate nest building by acting on brain regions controlling MB in other mammals. Nonhormonal factors like type of lodging and the doe's social rank influence nursing and milk production. The concurrency of pregnancy and lactation, the display of nonselective nursing, and the rapid growth of altricial young - despite a minimal effort of maternal care - have prompted the study of mother-young affiliation, neurodevelopment, and weaning. Neurohormonal mechanisms, common to other mammals, plus additional strategies (perhaps unique to rabbits) allow the efficient, adaptive display of MB in multiple settings.
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Experiment 1. One hundred and twenty-five lactations from 88 New Zealand × Californian does were used to study the influence of high fat diets on the performance and milk yield of multiparous rabbit does in two high productivity situations: housed in hot conditions (minimum temperature above 24 °C) with eight pups (group H8), or housed in warm conditions (minimum temperature under 21 °C) with 11 pups (group W11). Starting from a control diet (diet C) with 26 g ether extract (EE) per kg dry matter (DM), two isoenergetic diets were formulated adding fat from vegetable sources up to 99 g EE per kg DM (diet V) or animal sources up to 117 g EE per kg DM (diet A). The lactating does showed similar food daily intakes (≃105 g DM per kg), therefore digestible energy intake of does on high fat diets was significantly higher (P < 0.001). The addition of fat to the diets increased (P < 0.001) milk yield of does (+21 and 24 g/day for diets V and A, respectively) and litter weight at weaning (P < 0.05), and decreased the number of pups replaced (P < 0.01) during lactation. Group H8 does had significantly lower DM intakes, litter growth rates and milk production levels than group W11 does (P < 0.001). Experiment 2. The effect of these diets on milk composition was determined in 62 lactations from 28 multiparous rabbit does, in which litter size was maintained at eight pups. Milk samples were collected manually on the 7th, 21st and 28th days of lactation. Milk of does given high fat diets, especially diet A, had higher fat and energy contents (P < 0.001) and a lower protein content (P < 0.001) than those given diet C. Milk of does given diet A had a greater DM content than those given the diets C or V (P < 0.001). There was a correlation between the fatty acid composition of milk and dietary fat. The proportion of odd chain fatty acids in the milk fat was lower for does given diet V (P < 0.05) than those given diet A. In conclusion, high fat diets were related to a higher milk yield and energy content of milk, allowing a higher litter weight gain and a lower mortality of sucking pups.
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La lapine peut être fécondée aussitôt après la mise bas ou tout au long de la lactation, et être simultanément gravide et allaitante. Néanmoins, la réceptivité des femelles est variable au cours de la lactation : elle est maximale aussitôt après la mise bas (proche de 100 %) et minimale 3-5 jours après (40-65 %). Bien que les résultats expérimentaux concernant les effets de la lactation sur le taux d’ovulation et la mortalité embryonnaire soient parfois contradictoires, la fertilité et la prolificité des lapines allaitantes sont globalement plus faibles que celles des lapines non allaitantes. En effet, la lactation a, d’une manière générale, un effet négatif sur le pourcentage de femelles ovulant (-26 %), le taux de gestation (-33 %), et la viabilité foetale (-10 %). De plus, la lactation entraîne une diminution de la croissance pondérale des foetus (-20 %). L’hyperprolactinémie et la faible progestéronémie chez les lapines simultanément gravides et allaitantes, ainsi que le déficit nutritionnel engendré par la production laitière, semblent être les principaux facteurs responsables des effets observés.
The main energy diets developed and evaluated in recent decades for reproductive rabbit does are reviewed, with the emphasis on the effect of the energy source (animal fat, vegetable oil, and cereal starch) used. During gestation, energy supplementation of diets usually produces a decrease in feed intake due to energy intake regulation, but in some cases females are unable to regulate their feed intake with high-starch diets, leading to excessive energy intake. This overfeeding can cause fattening of does, sometimes related to greater pup mortality at birth. During lactation, reproductive rabbit does clearly increase their energy intake when fed with fat-enriched diets. This energy supplement is mainly utilized to increase their milk energy production (higher milk yield with a higher energy content), and higher litter growth and survival is consequently observed with fat-enriched diets. However, higher milk yield of these does is usually related to a greater negative energy balance and lower fertility values. In lactating does given cereal starch-enriched diets, primiparous rabbit does, whose voluntary intake is physically limited, usually show a higher energy intake, whereas multiparous does even decrease their energy intake. In any case, milk yield and composition of does given starch-enriched diets are not improved and may even worsen, negatively affecting litter performance and survival. However, does fed high-starch diets frequently present better energy balance during lactation as a consequence of their lower milk yield (lower lactation strain). Therefore, the addition of animal fat to the diet seems to improve the utilization of ingested energy for milk production, whereas the inclusion of higher dietary starch content can decrease the negative energy balance that reproductive rabbit does usually experience. The results obtained with vegetable oil-added diets are between those observed for animal fat- and starch-supplemented diets, showing similar milk production and litter performance but with lower body reserve depletion.
New Zealand × Californian rabbit does were offered ad libitum three diets: diet A, with 960 g lucerne per kg dry matter (DM), having 8•7 MJ digestible energy (DE) and 108 g digestible protein (DP) per kg DM; diet AF with 920 g lucerne and 50 g animal fat per kg DM, having 9•6 MJ DE and 105 g DP per kg DM; and diet C, as a control diet having 12•0 MJ DE and 122 g DP per kg DM. Productive parameters were measured for the first five parities, and food intake and milk yield during the first two parities. In experiment 1, 79 does (342 parities) were housed in a cooled building, litters were standardized to eight kits and weaned at 28 days of age. DM intake during lactation was lower (P < 0•001) but DE intake, milk yield and litter growth were higher for group C. Values for does on diet AF generally were between those of groups A and C. Average results for groups A, AF and C were respectively: 59, 65 and 51 days for the parturition interval; 160, 170 and 193 g for daily milk output in the first two lactations; 3•7, 4•0 and 4•5 kg for litter weight at weaning. In experiment 2, 64 does (294 parities) were housed in a climatic chamber at a constant temperature of 30oC, litters were standardized to six kits and weaned at 35 days of age. DM intake during lactation was lower (P < 0•001) but milk yield and litter growth were higher (P < 0•001) for C does. Average results for groups A, AF and C were respectively: 70, 70 and 56 days for parturition interval; 106, 128 and 128 g for daily milk output in the first two lactations; 3•7, 4•4 and 4•4 kg for litter weight at weaning. Lucerne-based diets allowed a reasonable performance of reproductive rabbit does in the long term, even under hot conditions.
In a search for alternatives of in-feed antibiotics, the antimicrobial activity of caprylic (C8:0), capric (C10:0) and oleic (C18:1) acid was investigated in pure cultures of 19 strains of rumen and rabbit caecal bacteria, and in incubations of the rumen and rabbit caecal contents. In glucose-grown bacterial cultures the minimum inhibitory concentration (MIC) of caprylic acid ranged from 1 to 3 μl·ml-1. Two strains of Bacteroides ovatus were less susceptible to capric than to caprylic acid. In other strains, the MIC of capric acid was 0.25-0.50 μl·ml-1. The growth of most strains was not much affected by oleic acid. An exception to this were rumen bacteria Butyrivibrio fibrisolvens (MIC from < 0.05 to 1 μl·ml-1) and Lachnospira multiparus (MIC of 0.25 to 1 μl·ml-1). In incubations of the rumen and caecal contents caprylic and capric acid decreased the production of volatile fatty acids and gas, and increased production of lactate. In latter incubations the inhibitory effects of caprylic and capric acid were similar. In incubations of the rumen contents, capric acid was more efficient than caprylic acid when supplied at low concentrations (<1.25 μl·ml-1), but less efficient when supplied at 2.5 and 5 μl·ml-1. Effects of oleic acid in rumen and caecal cultures were not significant, except the increase in production of lactate by rumen microorganisms. It can be concluded that microorganisms of the animal digestive tract are susceptible to inhibition by caprylic and capric acid added to microbial cultures at fairly low concentrations. Oleic acid was far less effective.
A two factorial experiment using 88 hybrid does of different age was undertaken to quantify the effects of litter weight at birth (<450, 450-650 vs. >650 g) and number of kids assigned (7, 8 or 9 kids per doe) on milk performance of the does and milk intake and growth performance of the kids. Litters were exchanged and balanced out completely. Milk performance of the does were measured by weighing the does before and after sucking twice per week during the first three weeks of lactation. Body weight development and milk intake of the kids were measured by weighing the kids weekly. Litter weight at birth and number of kids assigned significantly influenced milk performance of the does. Special attention is given to a significant interaction between both factors under investigation. Milk performance of does with high litter weight at birth (≥450 g) was strongly influenced by the number of kids assigned, whereas no effect was found in does with litter weight at birth below 450 g.