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Milk production potential in Maghrebi she-camels
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Milk production potential in Maghrebi she-camels Essmat Bakry Abdalla a , Abd El-Halim Anis Ashmawy a , Mohammed Hamdy Farouk b,∗ , Omar Abd El-Rahman Salama c , Farouk Abdalla Khalil a , Ahmed Fathy Seioudy c a b c
Anim. Prod. Dept., Fac. Agric., Ain Shams Univ., Cairo, Egypt Anim. Prod. Dept., Fac. Agric., Al-Azhar Univ., Nasr City, Cairo, Egypt Camel Res. Dept., Anim. Prod. Res. Institute, Agric. Res. Center, Giza, Egypt
a r t i c l e
i n f o
Article history: Received 24 August 2014 Received in revised form 4 November 2014 Accepted 5 November 2014 Available online xxx Keywords: Dairy camel Milk yield Milk composition Lactation curve Egyptian condition
a b s t r a c t Ten multiparous Maghrebi dairy she-camels (Camelus dromedarius L.) were used immediately after winter calving to study the chemical composition of milk through lactation. In addition, between 2004 and 2011, 748 records of 43 Maghrebi she-camels during 73 lactations were analyzed for evaluating their potential milk yield (MY) and lactation curve characteristics. The effects of some environmental factors on MY and milk composition was studied. The highest MY was recorded in sixth parity camels (1860 ± 54 l/lactation), which was significantly higher (P < 0.05) than MY at the first parity (1240 ± 44 l/lactation). Stillbirth was associated with a decline of 10% in MY when at 6 months of age. The highest MY was recorded at mid lactation (∼3 month in lactation), while the lowest MY was recorded at late lactation. MY of winter calving camels (December to May) was higher by 13.2% (1652–1458 l/lactation) in comparison to summer calving camels (June to November). The average content of protein in colostrum (at the first day postpartum) was 14.0% and that of fat 0.27%. The average contents of protein, fat, ash, lactose and total solids in milk were 3.01, 3.06, 0.69, 4.33, and 11.06%, respectively. Milk components were affected by lactation, except lactose, which its content was constant throughout lactation. Fat content ranged between 2.5 and 3.7%. The lowest content of fat was recorded at the 5th month of lactation, which corresponded with the lactation peak. Milk protein content ranged between 2.3 and 3.0%, with a minimal value at the 5th month of lactation. The trend in total solids content was similar to the trend in milk fat and protein contents. The wide range in MY points on the significant potential to increase the productivity of this breed. © 2014 Elsevier B.V. All rights reserved.
1. Introduction Increasing human population challenge food security and evoke the need to explore new resources of food, such as camel products (Faye and Konuspayeva, 2012). Nutritional benefits of camel milk components have
∗ Corresponding author at: Animal Production Department, Faculty of Agriculture, Al-Azhar University, Nasr City, 11884 Cairo, Egypt. Tel.: +20 1100859522; fax: +20 24011710. E-mail addresses: [email protected], [email protected] (M.H. Farouk).
been demonstrated by many authors (Kenzhebulat et al., 2000; Mal et al., 2006; Lorenzen et al., 2011). Milk of camel have several positive nutraceutical characteristics, such as anti-cancer (Magjeed, 2005), anti-diabetic (Agarwal et al., 2003; Agrawal et al., 2011) and hypo-allergic properties (Shabo et al., 2005). Milk yield (MY) in the dromedary camels has range widely (3.5–20 kg) (Jianlin, 2005). It has been suggested that MY and composition in camels is influenced by environmental conditions, time of milking and number of milking (Iqbal et al., 2001; Ayadi et al., 2009; Al Haj and Al Kanhal, 2010; Aljumaah et al., 2011). However, there is a debate regarding the relative importance of those factors. Production management was considered by Aljumaah et al. (2012) as one of the most important factors that affect MY, whereas Khaskheli et al. (2005) argued that seasonal variations in environmental conditions and geographical
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Please cite this article in press as: Abdalla, E.B., et al., Milk production potential in Maghrebi she-camels. Small Ruminant Res. (2014), http://dx.doi.org/10.1016/j.smallrumres.2014.11.004
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origins of the camels are the most important factors that affect camel MY and milk composition. Owing to the remarkable adaptation of camels to arid environment, large quantities of milk can be produced by she-camels under desert conditions for a long time. Milk yield of the Maghrebi shecamels under traditional extensive conditions averages 2.0 l/d though, under more favorable conditions, it ranges between 6 and 12 l/d (Ayadi et al., 2009), which suggest that the MY potential of this breed is greater than that recoded under the traditional extensive conditions. In a recent experiment, an average MY of 2200 ± 925 l/12.5 month of lactation (390–5310 l in 6–19 month) were recorded in Saudi Arabian camels that were exploited under intensive conditions (Musaad et al., 2013). Lactation curve and milk production performance in camels are not well characterized, unlike the situation in dairy cattle (Adediran et al., 2012; Musaad et al., 2013). The aim of this study was to evaluate the factors which affect MY and composition of the Maghrebi dairy she-camels under typical Egyptian conditions as a basis for future improvement of the MY by genetic selection and improved management. 2. Material and methods The current study was jointly planned by the Department of Animal Production, Faculty of Agriculture, Ain Shams University and the Department of Camel Research, Animal Production Research Institute, Agricultural Research Center. The study was carried out in the Center of Studies and Development of Camel Production, Marsa Matrouh Governorate (Northwest Egypt, 500 km from Cairo), belonging to the Animal Production Research Institute, Dokki, Giza, Egypt through a period from 2004 to 2012. 2.1. Animals and management The data on MY was collected between 2004 and 2011 and included 748 records of 43 Maghrebi she-camels during 73 lactations. In addition, 100 records of ten multiparous Maghrebi dairy she-camels (9.3 ± 2.6 years of age at their 3.6 ± 1.7 parity) were used directly after winter calving in season of 2011/2012 to study the effects of month of lactation, month of calving, mortality of calf, parity and milk yield on the chemical composition of milk.
over the period from 2004 to 2011. At each milking in season (2011/2012) from the ten she-camels, the MY was recorded using hand milking and milk samples (100 ml) were collected from each camel in the morning, once daily throughout the first week after parturition for analysing colostrum and early lactation milk composition and then once monthly until the end of lactation. Whole milk samples were stored frozen at −20 ◦ C without adding preservatives for chemical analysis (total solids, fat, protein, ash, and lactose). 2.5. Milk composition analysis Milk samples were analyzed as follows: total solids and ash contents were determined according to the method described by the Association of Analytical Communities (AOAC, 1990). The total nitrogen content of milk was measured by the Kjeldahl method according to the International Dairy Federation (IDF, 1993) instructions, where a nitrogen conversion factor of 6.38 was used to calculate total protein content. Milk fat content was determined by the Gerber method according to Ling (1963). Lactose was analyzed by an enzymatic assay (Lactose/d-Galactose UV-method; Boehringer Mannheim/R-Biopharm, Darmstadt, Germany). 2.6. Statistical analysis The data of milk production were statistically analyzed according to Statistical Analysis System (SAS, 1996) using general linear model (GLM) procedure by using the following model: Yijklmn = + Pi + Gj + CMk + CSl + CYm + b(x − x¯ ) + eijklmn where Yijklmn = an observation (total milk yield); is the overall mean; Pi = the fixed effect of ith parity, i = 1, 2, . . ., 8; Gj = the effect of jth gender, j = male or female; CMk = the effect of kth calf mortality, k = dead at stillbirth, 2, 4, 6 months of age and live; CSl = the effect of lth calving season, l = first interval (December to May) and second interval (June to November); CYm = the effect of mth calving year, m = 2004, 2005, . . .., 2011; b = partial regression coefficient of total milk yield (y) on lactation period (x), x¯ = average of lactation period and eijklmn = residual term and∼NID (0, 2 e). The data of milk composition was statistically analyzed by using the following model:
2.2. Feeding system
Yijklmn = + Pi + Gj + CMk + Cmol + LMm + b(x − x¯ ) + eijklmn
According to the management system applied in the farm, ration was offered to each animal twice daily at 8 a.m. and 5 p.m. The ration consisted of 4.5 kg DM of a forage mixture (Berseem clover hay, Trifolium alexandrinum; and rice straw) with some of fresh Mediterranean saltbush, Atriplex halimus L. and 3.5 kg DM of a commercial feed concentrate mixture (Ministry of Agriculture, Al-Salam, Cairo, Egypt) based on wheat bran, yellow corn, decorticated cotton seed, cane molasses, salt and minerals. The composition on a dry matter basis was dry matter, 11.0%; total digestible nutrients, 62%; crude protein, 12%; crude fiber, 15%; total fat, 4%. Free access to clean water was provided at all times by a water tanks.
where Yijklmn = milk component (total solids, protein, fat, ash or lactose); is the overall mean; Pi = the fixed effect of ith parity, i = 1, 2 and 7; Gj = the effect of jth gender, j = male or female; CMk = the effect of kth calf mortality, k = dead and live; Cmol = the effect of lth calving month, l = January, February, March and April; LMm = the effect of mth lactation month, m = 1, 2, . . ., 10; b = partial regression coefficient of milk component (y) on total milk yield (x), x¯ = average of lactation period and eijklmn = residual term and∼NID (0, 2 e). The data of milk composition of colostrum was statistically analyzed by using the following model:
2.3. Routine milking During the first 3 months, the calves were with their mothers and exclusively suckled their milk. After the 3rd month, the calves were separated and fed alfalfa hay and concentrate ad libitum. The camels were milked twice-daily (08:00 and 20:00 h) by hand milking. Milk let-down was induced by bringing individually the calves to their mothers and allowing them to suckle only the two right teats of the udder, whereas the two left teats were hand milked by an experienced farmer. The calves were weaned at sixth month of age, and the lactating camels were handmilked twice daily at 8:00 and 20:00 h without calf suckling until being dried off at month 12 of lactation. After calves’ separation, Milk let-down was induced by bringing calves to their mothers for sucking the teats to stimulate the milk let-down then the mothers were milked for the whole udder by hand milking. However, lactation curve data were collected from animals that were milked for 45–707 days using the records. 2.4. Experimental design Milk production of the she-camels was obtained from the 748 milk records of 73 lactations of 43 Maghrebi she-camels during 73 lactations
Yijkl = + Pi + Gj + LDk + eijkl where Yijkl = milk component (protein or fat); is the overall mean; Pi = the fixed effect of ith parity, i = 1, 2 and 7; Gj = the effect of jth gender, j = male or female; LDk = the effect of kth lactation day, k = 1, 2, . . ., 6 and eijkl = residual term and ∼NID (0, e 2 ). The differences between means of experimental groups were separated by protected Least Significant Difference (LSD) using 5% as a level of significance.
3. Results and discussion 3.1. Lactation curve 3.1.1. General description of milk productivity One of the many factors that affect MY is lactation length (Musaad et al., 2013). Lactation length in the present study ranged between 45 and 707 days, with an average of 353 ± 152 days (approximately 12
Please cite this article in press as: Abdalla, E.B., et al., Milk production potential in Maghrebi she-camels. Small Ruminant Res. (2014), http://dx.doi.org/10.1016/j.smallrumres.2014.11.004
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Fig. 1. Lactation curve of she-camels based on weekly data (n = 73 lactations) for 101 weeks of lactation.
months). Considering the total length of lactation, the mean MY ranged from 201 to 3197 l/lactation with an average of 1612 ± 710 l/lactation. The MY at start of lactation was 34.3 ± 3.5 l/week and peak MY was 55.0 ± 3.5 l/week; 12 weeks were needed to rich peak MY. After the peak was reached, MY decreased gradually until it leveled at 19.4 ± 12.3 l/week at the end of lactation in the 101th week (Fig. 1). A period of persistency in MY was recorded between the twelfth week of lactation (55 ± 3.5 l/week) and the twentieth week (54 ± 3.5 l/week). 3.1.2. Lactation curve according to parity and age The shape of the lactation curve was depended on initial MY, peak yield and persistency. The lowest MY (P < 0.05) was recorded at the first and the second parities than 4th to 8th parities, with an average MY 28 and 29.6 l/week, respectively (Table 1). The highest MY was recorded between the fifth and eighth parities with an average MY of 39.9 l/week. In some cases, peak of MY was recorded at the 5th one also found by Musaad et al. (2013). Lactation curves increased regularly up to the peak value and then were followed by a slight decay curve. However, the pattern in the third parity camels was different: in those camels peak in MY was reached in early lactation (week 8) and then the MY remained stable until the end of lactation. In camels at their second, fourth and fifth parities, the peak occurred earlier, in the 8th and 4th weeks postpartum, respectively. Differently, in camels at their first, sixth, seventh and eighth parities, the peak occurred later at the 16th, 14th, 12th and 12th week, respectively. The highest MY (1860 ± 54 l/lactation) was recorded at the sixth parity, which was significantly higher than MY by first parity camels (1240 ± 44 l). The patterns of lactation according to the lactation number as these two factors were closely correlated between each other (r = 0.736; P < 0.05).
3.2. Milk composition 3.2.1. Colostrum and early lactation In general, the content of total protein (TP) was highest (14% of DM) just after the calving (i.e., during the secretion of colostrum) and then it gradually decreased until it reached stability at the end of the first week of lactation (7.8%). The content of TP continued to decrease gradually to a level of 3.6 ± 0.3% at the sixth (colostrum termination) day of lactation (Fig. 2). In the course of the first 4 stages: a fall from 14% on the first day of lactation to 3.6% on the sixth day of lactation. A similar trend in reduction in milk colostrum and milk TP in milk at early lactation is in consistent with other reports (Ohri and Joshi, 1961; Abu-Lehia et al., 1989; AbuLehia, 1991; Zhang et al., 2005). Konuspayeva et al. (2010) found that TP decreased from 17.2 to 4.2% in 7 days. The high content of TP in during the colostrum secretion can be explained by the high content of immunoglobulins in mammary secretion at this stage. The fat content showed an opposite trend to the TP content in colostrum: it had the lowest content just after the calving (0.27%) and then gradually increased (1.2 at day 2 and 3.5 at day 6) until stability at the end of the first week of lactation. Our results are consistent with those of Merin et al. (2001). A similar pattern, but with higher or lower fat contents were found in other breeds of camels (Gobran and Izzeldin, 1997; Gaili et al., 2000; Faye et al., 2008). 3.2.2. Milk composition between early and late lactation 3.2.2.1. Total solids. The total solids (TS) content of camel milk varied from 7.52 to 14.56% with an average of 11.06 ± 1.45% (Table 3). These results are in the line with those of Khaskheli et al. (2005) (7.76–12.13% with an average of 9.74 ± 0.49%). In some studies, lower content of TS were found (Hassan et al., 1987; Elamin and Wilcox, 1992).
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Table 1 Characteristics of the lactation curve according to different parities. Parity
Number of records
1 2 3 4 5 6 7 8
92 120 187 124 113 60 40 12
Average milk yield, l
Peak
Per week
Per lactation
28.0 29.6 30.8 37.3 39.9 34.6 31.9 39.9
1240 1214 1297 1494 1772 1860 1854 1706
± ± ± ± ± ± ± ±
43 39 34 37 39 54 59 93
Week number
(l/week)
16 8 8 8 4 14 12 12
37 40 39 51 54 48 49 58
Fig. 2. Changes in protein and fat contents of colostrum of she-camels (n = 100).
Variation in TS content might have been a consequence of negative effect of heat stress on feed intake and thus protein, fat and lactose content (Silanikove, 2000). However, it seems that very little is known about the effect of heat stress on feed intake in camels and further research in this line is needed. 3.2.2.2. Proteins. Mean TP content was 3.01 ± 0.36% and it ranged between 2.23 and 3.88% (Table 3), in agreement with the finding of Konuspayeva et al. (2009) (2.15–4.90%). However, Meiloud et al. (2011) found lower TP content (2.50 ± 0.10%). The variation in TP content most likely reflects the effects of parity, season and lactation stages (Table 3). 3.2.2.3. Fat. Fat content in the camel milk ranged between 0.80 and 4.30% with an average of 3.06 ± 0.70%. Variation in MF was explained by Khaskheli et al. (2005) 1.8–5.0% with an average of 2.63 ± 0.40%) and Konuspayeva et al. (2009) 1.2–6.4% with an average of 3.5 ± 1.0%. The low percentage of MF in some camels probably reflects poor nutritional conditions that are typical to desert habitat. 3.2.2.4. Ash. The total ash varied from 0.50 to 0.89% with an average of 0.69 ± 0.11%, in consistent with the finding of Konuspayeva et al. (2009) 0.60–0.90% and
average of 0.79 ± 0.07%. Variations in mineral content were attributed to breed differences, feeding, analytical procedures (Mehaia et al., 1995) and water intake (Haddadin et al., 2008). Fouzia et al. (2013) suggested that the relatively high content of ash in camel milk may be related to intake of salty forage, such as Atriplex and Acacia, which in turn may lead to an increase in the chloride content of the milk. However, further research in this line is needed as the diet fed in this experiment was not particularly high in minerals.
3.2.2.5. Lactose. A wide variation in milk lactose (ML) content was observed in this study; where it ranged from 1.54 to 6.56% with an average of 4.33 ± 1.04%, in consistent with (Konuspayeva et al., 2009) 2.40 to 5.80% with an average of 4.4 ± 0.7%). These vast changes in ML are unusual among dairy farm animals (cow, goats and sheep). In some previous studies, ML was found to be the only milk component that remained almost unchanged over a season (Haddadin et al., 2008) and under hydrated or dehydrated conditions (Yagil and Etzion, 1980). Thus, further research on this issue with direct analysis on milk lactose is needed to understand the nutritional and physiological factors that cause the large variations in ML in the present study.
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E.B. Abdalla et al. / Small Ruminant Research xxx (2014) xxx–xxx Table 2 Least-square means and their standard error for parity, calving season, calf mortality and lactation period and their effect on total milk yield of she-camels. Factors
Number of records
Total milk yield, l
Parity 1 2 3 4 5 6 7 8
92 120 187 124 113 60 40 12
1240a ± 43 1214bc ± 39 1297c ± 34 1494dg ± 37 1772eh ± 39 1860f ± 54 1854gf ± 59 1706dh ± 93
Calving season First season Second season
652 96
1651a ± 27 1458b ± 39
Calf mortality at Stillbirth 2 months of age 4 months of age 6 months of age Live
134 73 9 28 504
1474a ± 36 1530b ± 40 1575c ± 96 1576c ± 59 1618c ± 20
Lactation period as a covariate
748
4.2 ± 0.08 l/d
Mean
1612 ± 9.5
The means in a column with a similar superscript are not significantly different (P > 0.05).
3.3. Factors affecting milk yield and its composition 3.3.1. Factors affecting milk yield 3.3.1.1. Parity. In the present experiment the effect of parity on total MY was significant increase in MY between the first to sixth parity and after the sixth parity, total MY significantly decreased from the sixth to the eighth parity (Table 2). The results of the present study, fairly agree with those of Al-Saiady et al. (2012) who reported that the lowest MY was observed at the first, second and fourth lactation, while, the highest milk productivity was observed at the third and sixth parity of lactation. Similarly, Raziq et al. (2008) found that the highest MY was at the fifth parity with a significant difference between the first parity and all the other parities. However, these authors indicated that the highest MY was recorded in 5th and 6th parities. Musaad et al. (2013) reported that peak yield varied significantly between parities where the maximum peak yield was reached at the eighth parity. On average, in she-camels, optimal production capacity was reached between the fifth and sixth parities, which is later than in dairy cows, whose maximum productivity is generally observed at the third parity (Horan et al., 2005). Further research in this line is needed and factors such as the development and size of the udder increase of body size over that of the first lactation animal, along with a larger mammary gland for the secretion of milk need to be considered. 3.3.1.2. Calving season. The calving season (December to May and June to November) significantly affected total milk yield. MY was significantly lower in the second season
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(June to November) in comparison to MY in the first season (December to May) (by 13.2% from 1652 to 1458 l/lactation; Table 2). The partition of the calving between the two seasons was 87 and 13% for the first and second seasons, respectively. The results of the current study are similar to those reported by Musaad et al. (2013). In consistent with Musaad et al. (2013), the largest persistency in MY, peak of MY were found in she-camels that calved between November to February (Musaad et al., 2013). Lack of heat stress is most likely the most significant factor that explains the higher MY in camels calving between November and February. In consistent with results in dairy cows (Barash et al., 2001) the lack of heat stress is more important than the negative effect of shorter days that are typical to this season on MY. 3.3.1.3. Calf mortality. The mortality rate of calf was 32% in this study (Table 2). The mortality of calf significantly affected total MY. In general, total MY decreased significantly when camel calves died during lactation as compared with those which carried calves until weaning (Table 2). The highest decline in total MY (10%) was obtained when stillbirth occurred, or when calf mortality happened in early lactation (6% at two months of age) in comparison to calves death occurring at later stages (3% between four and six months of age). Mortality percentage of new-born camels was frequently found to be high (50%) in many areas of eastern Africa (Hussein, 1987). The lack of suckling is considered as a major factor, which restrict MY because the suckling stimulation is essential for milk let-down. Thus, high calf mortality is an important constraint to increase productivity in she-camels (present results). Nagy et al. (2013) found if camels are trained to machine milking, calf is not necessary for milking the camels, which suggest that a solution to this problem is available. 3.3.1.4. Lactation period. The length of lactation affected significantly the total MY. Partial regression coefficient between total MY and lactation length was 4.2 l/day. In other words, under the present conditions, when the lactation period increased by one day, the total MY increased by 4.2 l. 3.3.2. Factors affecting milk composition 3.3.2.1. Parity. The lactation number affected significantly milk TP, ash and MF contents, while, there were no significant effect of lactation number on TS and ML. Advance in lactation number was associated with decline in most milk components. First lactation was characterized with high contents of TP, MF, ML and TS (3.29, 3.70, 3.95 and 10.65% in average, respectively). The seventh lactation was characterized with low contents of TP, MF, ML and TS (2.27, 2.71, 3.80 and 10.12% in average, respectively). Ash content increased with advancing of the lactation number; however, the lowest value of ash content was recorded at the first lactation while the highest level was at the seventh lactation (Table 3). The results of this study in fat are consistent with those of Aljumaah et al. (2012).
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Table 3 Least-square means and their standard error for parity, calf mortality, calving month and lactation month and their effect on milk components of she-camels. Factors
No. of records
Total solids %
Protein %
Fat %
Ash %
Lactose %
Parity 1 2 7
70 10 20
10.65a ± 0.4 10.51a ± 0.7 10.12a ± 0.6
3.29a ± 0.1 2.41b ± 0.1 2.27c ± 0.1
3.70a ± 0.2 3.03ab ± 0.3 2.71b ± 0.3
0.65a ± 0.02 0.75b ± 0.04 0.91c ± 0.04
3.95a ± 0.3 3.81a ± 0.6 3.80a ± 0.5
Calf mortality Dead Live
10 90
9.9a ± 0.6 10.9a ± 0.3
2.63a ± 0.1 2.68a ± 0.1
3.14a ± 0.3 3.15a ± 0.1
0.79a ± 0.04 0.75a ± 0.02
3.4a ± 0.5 4.2a ± 0.2
Calving month January February March April
20 40 10 30
10.36a 10.79a 10.48a 10.07a
± ± ± ±
0.4 0.4 0.7 0.6
3.20a 2.45b 2.50c 2.49cd
± ± ± ±
0.1 0.1 0.1 0.1
Lactation month 1 2 3 4 5 6 7 8 9 10
10 10 10 10 10 10 10 10 10 10
11.71 10.51 11.22 9.78 9.34 10.37 9.32 9.91 10.57 11.52
± ± ± ± ± ± ± ± ± ±
0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5
3.00 2.76 2.80 2.49 2.33 2.45 2.40 2.48 2.76 3.08
± ± ± ± ± ± ± ± ± ±
0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07
Mean
11.06 ± 0.1
3.01 ± 0.02
2.33a 3.35bd 3.57bc 3.35cd
± ± ± ±
0.3 0.2 0.3 0.2
3.64 3.24 3.08 2.62 2.54 2.88 3.10 3.29 3.32 3.75
± ± ± ± ± ± ± ± ± ±
0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22
3.06 ± 0.05
0.77a 0.79bc 0.83c 0.69d
± ± ± ±
0.04 0.02 0.04 0.03
3.92a 4.01a 3.76a 3.73a
± ± ± ±
0.3 0.4 0.6 0.5
0.75 0.75 0.72 0.73 0.74 0.74 0.77 0.81 0.84 0.84
± ± ± ± ± ± ± ± ± ±
0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03
4.30 4.13 4.43 3.92 3.70 4.05 3.28 3.29 3.64 3.82
± ± ± ± ± ± ± ± ± ±
0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4
0.69 ± 0.01
4.33 ± 0.1
The means in a column with a similar superscript are not significantly different (P > 0.05).
3.3.2.2. Calf mortality. The effect of calf mortality on milk composition was not significant. 3.3.2.3. Calving month. The month of calving affected significantly milk TP, MF and ash contents, while, the contents of TS and ML were not affected. TS and ML contents were the highest in February; while the lowest values were recorded in April (Table 3). Milk TP content was the highest in January while the lowest value was observed in February. The highest value of MF content was observed in March while the lowest value was recorded in January. The present results are similar to that reported by Haddadin et al. (2008). Whereas, Abdoun et al. (2007) noted that MF content was highest (P < 0.01) in hot summer and decreased significantly during both winter and rainy seasons. 3.3.2.4. Lactation month. Lactation month affected significantly milk TP, MF, ash and TS while ML content was not affected. The values of MF, TP and TS were higher during the first stage of lactation (Early-lactation) as compared to the second one (Mid-lactation) (from 3.00, 3.64 and 11.71%, respectively, at the first month of lactation to 2.33, 2.54 and 9.34%, respectively, at the fifth month of lactation (Table 3). At the last stage of lactation (Late-lactation), the values of MF, TP and TS gradually increased to similar levels to those recorded at the first stage of lactation (Early-lactation). Milk TP, MF and TS gradually decreased during the first stage of lactation. Ash content increased significantly with the progress of the lactation from 0.75% at the first month of lactation to 0.84% at the last month of lactation (10th month). ML content varied from 3.28 to 4.43% (mean, 3.86%). The current
results are consistent with previous reports (Alshaikh and Salah, 1994; Gaili et al., 2000; Zeleke, 2007; Aljumaah et al., 2012). 3.3.2.5. Milk yield. Milk yield was significantly associated with milk TP and ash contents while TS, fat and ML contents were not affected by MY. Partial regression coefficient of TS, TP, MF, ash and ML on total milk yield was 0.001 ± 0.007, 0.0003 ± 0.0001, 0.0004 ± 0.0003, 0.0001 ± 0.0002 and 0.00008 ± 0.00006%/l, respectively. In other words, when the milk yield increases by 1 l, the concentration of TS, TP, MF, ash and ML were also increased by the mentioned values. 4. Conclusion Our results can contribute for increasing the efficiency of raising she-camels for milk in desert areas by adjusting the nutrition to the lactation pattern and milk yield. The wide range of milk yield of Maghrebi she-camel indicates the high potential of long-term selection programs to select for high milk yield by this breed. In turn, increasing milk yield will contribute to increase food security in areas vulnerable for food shortage. Conflict of interest None. References Abdoun, K.A., Amin, A.S., Abdelatif, A.M., 2007. Milk composition of dromedary camels (Camelus dromedarius): nutritional effects and
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Milk production potential in Maghrebi she-camels Essmat Bakry Abdalla a , Abd El-Halim Anis Ashmawy a , Mohammed Hamdy Farouk b,∗ , Omar Abd El-Rahman Salama c , Farouk Abdalla Khalil a , Ahmed Fathy Seioudy c a b c
Anim. Prod. Dept., Fac. Agric., Ain Shams Univ., Cairo, Egypt Anim. Prod. Dept., Fac. Agric., Al-Azhar Univ., Nasr City, Cairo, Egypt Camel Res. Dept., Anim. Prod. Res. Institute, Agric. Res. Center, Giza, Egypt
a r t i c l e
i n f o
Article history: Received 24 August 2014 Received in revised form 4 November 2014 Accepted 5 November 2014 Available online xxx Keywords: Dairy camel Milk yield Milk composition Lactation curve Egyptian condition
a b s t r a c t Ten multiparous Maghrebi dairy she-camels (Camelus dromedarius L.) were used immediately after winter calving to study the chemical composition of milk through lactation. In addition, between 2004 and 2011, 748 records of 43 Maghrebi she-camels during 73 lactations were analyzed for evaluating their potential milk yield (MY) and lactation curve characteristics. The effects of some environmental factors on MY and milk composition was studied. The highest MY was recorded in sixth parity camels (1860 ± 54 l/lactation), which was significantly higher (P < 0.05) than MY at the first parity (1240 ± 44 l/lactation). Stillbirth was associated with a decline of 10% in MY when at 6 months of age. The highest MY was recorded at mid lactation (∼3 month in lactation), while the lowest MY was recorded at late lactation. MY of winter calving camels (December to May) was higher by 13.2% (1652–1458 l/lactation) in comparison to summer calving camels (June to November). The average content of protein in colostrum (at the first day postpartum) was 14.0% and that of fat 0.27%. The average contents of protein, fat, ash, lactose and total solids in milk were 3.01, 3.06, 0.69, 4.33, and 11.06%, respectively. Milk components were affected by lactation, except lactose, which its content was constant throughout lactation. Fat content ranged between 2.5 and 3.7%. The lowest content of fat was recorded at the 5th month of lactation, which corresponded with the lactation peak. Milk protein content ranged between 2.3 and 3.0%, with a minimal value at the 5th month of lactation. The trend in total solids content was similar to the trend in milk fat and protein contents. The wide range in MY points on the significant potential to increase the productivity of this breed. © 2014 Elsevier B.V. All rights reserved.
1. Introduction Increasing human population challenge food security and evoke the need to explore new resources of food, such as camel products (Faye and Konuspayeva, 2012). Nutritional benefits of camel milk components have
∗ Corresponding author at: Animal Production Department, Faculty of Agriculture, Al-Azhar University, Nasr City, 11884 Cairo, Egypt. Tel.: +20 1100859522; fax: +20 24011710. E-mail addresses: [email protected], [email protected] (M.H. Farouk).
been demonstrated by many authors (Kenzhebulat et al., 2000; Mal et al., 2006; Lorenzen et al., 2011). Milk of camel have several positive nutraceutical characteristics, such as anti-cancer (Magjeed, 2005), anti-diabetic (Agarwal et al., 2003; Agrawal et al., 2011) and hypo-allergic properties (Shabo et al., 2005). Milk yield (MY) in the dromedary camels has range widely (3.5–20 kg) (Jianlin, 2005). It has been suggested that MY and composition in camels is influenced by environmental conditions, time of milking and number of milking (Iqbal et al., 2001; Ayadi et al., 2009; Al Haj and Al Kanhal, 2010; Aljumaah et al., 2011). However, there is a debate regarding the relative importance of those factors. Production management was considered by Aljumaah et al. (2012) as one of the most important factors that affect MY, whereas Khaskheli et al. (2005) argued that seasonal variations in environmental conditions and geographical
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origins of the camels are the most important factors that affect camel MY and milk composition. Owing to the remarkable adaptation of camels to arid environment, large quantities of milk can be produced by she-camels under desert conditions for a long time. Milk yield of the Maghrebi shecamels under traditional extensive conditions averages 2.0 l/d though, under more favorable conditions, it ranges between 6 and 12 l/d (Ayadi et al., 2009), which suggest that the MY potential of this breed is greater than that recoded under the traditional extensive conditions. In a recent experiment, an average MY of 2200 ± 925 l/12.5 month of lactation (390–5310 l in 6–19 month) were recorded in Saudi Arabian camels that were exploited under intensive conditions (Musaad et al., 2013). Lactation curve and milk production performance in camels are not well characterized, unlike the situation in dairy cattle (Adediran et al., 2012; Musaad et al., 2013). The aim of this study was to evaluate the factors which affect MY and composition of the Maghrebi dairy she-camels under typical Egyptian conditions as a basis for future improvement of the MY by genetic selection and improved management. 2. Material and methods The current study was jointly planned by the Department of Animal Production, Faculty of Agriculture, Ain Shams University and the Department of Camel Research, Animal Production Research Institute, Agricultural Research Center. The study was carried out in the Center of Studies and Development of Camel Production, Marsa Matrouh Governorate (Northwest Egypt, 500 km from Cairo), belonging to the Animal Production Research Institute, Dokki, Giza, Egypt through a period from 2004 to 2012. 2.1. Animals and management The data on MY was collected between 2004 and 2011 and included 748 records of 43 Maghrebi she-camels during 73 lactations. In addition, 100 records of ten multiparous Maghrebi dairy she-camels (9.3 ± 2.6 years of age at their 3.6 ± 1.7 parity) were used directly after winter calving in season of 2011/2012 to study the effects of month of lactation, month of calving, mortality of calf, parity and milk yield on the chemical composition of milk.
over the period from 2004 to 2011. At each milking in season (2011/2012) from the ten she-camels, the MY was recorded using hand milking and milk samples (100 ml) were collected from each camel in the morning, once daily throughout the first week after parturition for analysing colostrum and early lactation milk composition and then once monthly until the end of lactation. Whole milk samples were stored frozen at −20 ◦ C without adding preservatives for chemical analysis (total solids, fat, protein, ash, and lactose). 2.5. Milk composition analysis Milk samples were analyzed as follows: total solids and ash contents were determined according to the method described by the Association of Analytical Communities (AOAC, 1990). The total nitrogen content of milk was measured by the Kjeldahl method according to the International Dairy Federation (IDF, 1993) instructions, where a nitrogen conversion factor of 6.38 was used to calculate total protein content. Milk fat content was determined by the Gerber method according to Ling (1963). Lactose was analyzed by an enzymatic assay (Lactose/d-Galactose UV-method; Boehringer Mannheim/R-Biopharm, Darmstadt, Germany). 2.6. Statistical analysis The data of milk production were statistically analyzed according to Statistical Analysis System (SAS, 1996) using general linear model (GLM) procedure by using the following model: Yijklmn = + Pi + Gj + CMk + CSl + CYm + b(x − x¯ ) + eijklmn where Yijklmn = an observation (total milk yield); is the overall mean; Pi = the fixed effect of ith parity, i = 1, 2, . . ., 8; Gj = the effect of jth gender, j = male or female; CMk = the effect of kth calf mortality, k = dead at stillbirth, 2, 4, 6 months of age and live; CSl = the effect of lth calving season, l = first interval (December to May) and second interval (June to November); CYm = the effect of mth calving year, m = 2004, 2005, . . .., 2011; b = partial regression coefficient of total milk yield (y) on lactation period (x), x¯ = average of lactation period and eijklmn = residual term and∼NID (0, 2 e). The data of milk composition was statistically analyzed by using the following model:
2.2. Feeding system
Yijklmn = + Pi + Gj + CMk + Cmol + LMm + b(x − x¯ ) + eijklmn
According to the management system applied in the farm, ration was offered to each animal twice daily at 8 a.m. and 5 p.m. The ration consisted of 4.5 kg DM of a forage mixture (Berseem clover hay, Trifolium alexandrinum; and rice straw) with some of fresh Mediterranean saltbush, Atriplex halimus L. and 3.5 kg DM of a commercial feed concentrate mixture (Ministry of Agriculture, Al-Salam, Cairo, Egypt) based on wheat bran, yellow corn, decorticated cotton seed, cane molasses, salt and minerals. The composition on a dry matter basis was dry matter, 11.0%; total digestible nutrients, 62%; crude protein, 12%; crude fiber, 15%; total fat, 4%. Free access to clean water was provided at all times by a water tanks.
where Yijklmn = milk component (total solids, protein, fat, ash or lactose); is the overall mean; Pi = the fixed effect of ith parity, i = 1, 2 and 7; Gj = the effect of jth gender, j = male or female; CMk = the effect of kth calf mortality, k = dead and live; Cmol = the effect of lth calving month, l = January, February, March and April; LMm = the effect of mth lactation month, m = 1, 2, . . ., 10; b = partial regression coefficient of milk component (y) on total milk yield (x), x¯ = average of lactation period and eijklmn = residual term and∼NID (0, 2 e). The data of milk composition of colostrum was statistically analyzed by using the following model:
2.3. Routine milking During the first 3 months, the calves were with their mothers and exclusively suckled their milk. After the 3rd month, the calves were separated and fed alfalfa hay and concentrate ad libitum. The camels were milked twice-daily (08:00 and 20:00 h) by hand milking. Milk let-down was induced by bringing individually the calves to their mothers and allowing them to suckle only the two right teats of the udder, whereas the two left teats were hand milked by an experienced farmer. The calves were weaned at sixth month of age, and the lactating camels were handmilked twice daily at 8:00 and 20:00 h without calf suckling until being dried off at month 12 of lactation. After calves’ separation, Milk let-down was induced by bringing calves to their mothers for sucking the teats to stimulate the milk let-down then the mothers were milked for the whole udder by hand milking. However, lactation curve data were collected from animals that were milked for 45–707 days using the records. 2.4. Experimental design Milk production of the she-camels was obtained from the 748 milk records of 73 lactations of 43 Maghrebi she-camels during 73 lactations
Yijkl = + Pi + Gj + LDk + eijkl where Yijkl = milk component (protein or fat); is the overall mean; Pi = the fixed effect of ith parity, i = 1, 2 and 7; Gj = the effect of jth gender, j = male or female; LDk = the effect of kth lactation day, k = 1, 2, . . ., 6 and eijkl = residual term and ∼NID (0, e 2 ). The differences between means of experimental groups were separated by protected Least Significant Difference (LSD) using 5% as a level of significance.
3. Results and discussion 3.1. Lactation curve 3.1.1. General description of milk productivity One of the many factors that affect MY is lactation length (Musaad et al., 2013). Lactation length in the present study ranged between 45 and 707 days, with an average of 353 ± 152 days (approximately 12
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Fig. 1. Lactation curve of she-camels based on weekly data (n = 73 lactations) for 101 weeks of lactation.
months). Considering the total length of lactation, the mean MY ranged from 201 to 3197 l/lactation with an average of 1612 ± 710 l/lactation. The MY at start of lactation was 34.3 ± 3.5 l/week and peak MY was 55.0 ± 3.5 l/week; 12 weeks were needed to rich peak MY. After the peak was reached, MY decreased gradually until it leveled at 19.4 ± 12.3 l/week at the end of lactation in the 101th week (Fig. 1). A period of persistency in MY was recorded between the twelfth week of lactation (55 ± 3.5 l/week) and the twentieth week (54 ± 3.5 l/week). 3.1.2. Lactation curve according to parity and age The shape of the lactation curve was depended on initial MY, peak yield and persistency. The lowest MY (P < 0.05) was recorded at the first and the second parities than 4th to 8th parities, with an average MY 28 and 29.6 l/week, respectively (Table 1). The highest MY was recorded between the fifth and eighth parities with an average MY of 39.9 l/week. In some cases, peak of MY was recorded at the 5th one also found by Musaad et al. (2013). Lactation curves increased regularly up to the peak value and then were followed by a slight decay curve. However, the pattern in the third parity camels was different: in those camels peak in MY was reached in early lactation (week 8) and then the MY remained stable until the end of lactation. In camels at their second, fourth and fifth parities, the peak occurred earlier, in the 8th and 4th weeks postpartum, respectively. Differently, in camels at their first, sixth, seventh and eighth parities, the peak occurred later at the 16th, 14th, 12th and 12th week, respectively. The highest MY (1860 ± 54 l/lactation) was recorded at the sixth parity, which was significantly higher than MY by first parity camels (1240 ± 44 l). The patterns of lactation according to the lactation number as these two factors were closely correlated between each other (r = 0.736; P < 0.05).
3.2. Milk composition 3.2.1. Colostrum and early lactation In general, the content of total protein (TP) was highest (14% of DM) just after the calving (i.e., during the secretion of colostrum) and then it gradually decreased until it reached stability at the end of the first week of lactation (7.8%). The content of TP continued to decrease gradually to a level of 3.6 ± 0.3% at the sixth (colostrum termination) day of lactation (Fig. 2). In the course of the first 4 stages: a fall from 14% on the first day of lactation to 3.6% on the sixth day of lactation. A similar trend in reduction in milk colostrum and milk TP in milk at early lactation is in consistent with other reports (Ohri and Joshi, 1961; Abu-Lehia et al., 1989; AbuLehia, 1991; Zhang et al., 2005). Konuspayeva et al. (2010) found that TP decreased from 17.2 to 4.2% in 7 days. The high content of TP in during the colostrum secretion can be explained by the high content of immunoglobulins in mammary secretion at this stage. The fat content showed an opposite trend to the TP content in colostrum: it had the lowest content just after the calving (0.27%) and then gradually increased (1.2 at day 2 and 3.5 at day 6) until stability at the end of the first week of lactation. Our results are consistent with those of Merin et al. (2001). A similar pattern, but with higher or lower fat contents were found in other breeds of camels (Gobran and Izzeldin, 1997; Gaili et al., 2000; Faye et al., 2008). 3.2.2. Milk composition between early and late lactation 3.2.2.1. Total solids. The total solids (TS) content of camel milk varied from 7.52 to 14.56% with an average of 11.06 ± 1.45% (Table 3). These results are in the line with those of Khaskheli et al. (2005) (7.76–12.13% with an average of 9.74 ± 0.49%). In some studies, lower content of TS were found (Hassan et al., 1987; Elamin and Wilcox, 1992).
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Table 1 Characteristics of the lactation curve according to different parities. Parity
Number of records
1 2 3 4 5 6 7 8
92 120 187 124 113 60 40 12
Average milk yield, l
Peak
Per week
Per lactation
28.0 29.6 30.8 37.3 39.9 34.6 31.9 39.9
1240 1214 1297 1494 1772 1860 1854 1706
± ± ± ± ± ± ± ±
43 39 34 37 39 54 59 93
Week number
(l/week)
16 8 8 8 4 14 12 12
37 40 39 51 54 48 49 58
Fig. 2. Changes in protein and fat contents of colostrum of she-camels (n = 100).
Variation in TS content might have been a consequence of negative effect of heat stress on feed intake and thus protein, fat and lactose content (Silanikove, 2000). However, it seems that very little is known about the effect of heat stress on feed intake in camels and further research in this line is needed. 3.2.2.2. Proteins. Mean TP content was 3.01 ± 0.36% and it ranged between 2.23 and 3.88% (Table 3), in agreement with the finding of Konuspayeva et al. (2009) (2.15–4.90%). However, Meiloud et al. (2011) found lower TP content (2.50 ± 0.10%). The variation in TP content most likely reflects the effects of parity, season and lactation stages (Table 3). 3.2.2.3. Fat. Fat content in the camel milk ranged between 0.80 and 4.30% with an average of 3.06 ± 0.70%. Variation in MF was explained by Khaskheli et al. (2005) 1.8–5.0% with an average of 2.63 ± 0.40%) and Konuspayeva et al. (2009) 1.2–6.4% with an average of 3.5 ± 1.0%. The low percentage of MF in some camels probably reflects poor nutritional conditions that are typical to desert habitat. 3.2.2.4. Ash. The total ash varied from 0.50 to 0.89% with an average of 0.69 ± 0.11%, in consistent with the finding of Konuspayeva et al. (2009) 0.60–0.90% and
average of 0.79 ± 0.07%. Variations in mineral content were attributed to breed differences, feeding, analytical procedures (Mehaia et al., 1995) and water intake (Haddadin et al., 2008). Fouzia et al. (2013) suggested that the relatively high content of ash in camel milk may be related to intake of salty forage, such as Atriplex and Acacia, which in turn may lead to an increase in the chloride content of the milk. However, further research in this line is needed as the diet fed in this experiment was not particularly high in minerals.
3.2.2.5. Lactose. A wide variation in milk lactose (ML) content was observed in this study; where it ranged from 1.54 to 6.56% with an average of 4.33 ± 1.04%, in consistent with (Konuspayeva et al., 2009) 2.40 to 5.80% with an average of 4.4 ± 0.7%). These vast changes in ML are unusual among dairy farm animals (cow, goats and sheep). In some previous studies, ML was found to be the only milk component that remained almost unchanged over a season (Haddadin et al., 2008) and under hydrated or dehydrated conditions (Yagil and Etzion, 1980). Thus, further research on this issue with direct analysis on milk lactose is needed to understand the nutritional and physiological factors that cause the large variations in ML in the present study.
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E.B. Abdalla et al. / Small Ruminant Research xxx (2014) xxx–xxx Table 2 Least-square means and their standard error for parity, calving season, calf mortality and lactation period and their effect on total milk yield of she-camels. Factors
Number of records
Total milk yield, l
Parity 1 2 3 4 5 6 7 8
92 120 187 124 113 60 40 12
1240a ± 43 1214bc ± 39 1297c ± 34 1494dg ± 37 1772eh ± 39 1860f ± 54 1854gf ± 59 1706dh ± 93
Calving season First season Second season
652 96
1651a ± 27 1458b ± 39
Calf mortality at Stillbirth 2 months of age 4 months of age 6 months of age Live
134 73 9 28 504
1474a ± 36 1530b ± 40 1575c ± 96 1576c ± 59 1618c ± 20
Lactation period as a covariate
748
4.2 ± 0.08 l/d
Mean
1612 ± 9.5
The means in a column with a similar superscript are not significantly different (P > 0.05).
3.3. Factors affecting milk yield and its composition 3.3.1. Factors affecting milk yield 3.3.1.1. Parity. In the present experiment the effect of parity on total MY was significant increase in MY between the first to sixth parity and after the sixth parity, total MY significantly decreased from the sixth to the eighth parity (Table 2). The results of the present study, fairly agree with those of Al-Saiady et al. (2012) who reported that the lowest MY was observed at the first, second and fourth lactation, while, the highest milk productivity was observed at the third and sixth parity of lactation. Similarly, Raziq et al. (2008) found that the highest MY was at the fifth parity with a significant difference between the first parity and all the other parities. However, these authors indicated that the highest MY was recorded in 5th and 6th parities. Musaad et al. (2013) reported that peak yield varied significantly between parities where the maximum peak yield was reached at the eighth parity. On average, in she-camels, optimal production capacity was reached between the fifth and sixth parities, which is later than in dairy cows, whose maximum productivity is generally observed at the third parity (Horan et al., 2005). Further research in this line is needed and factors such as the development and size of the udder increase of body size over that of the first lactation animal, along with a larger mammary gland for the secretion of milk need to be considered. 3.3.1.2. Calving season. The calving season (December to May and June to November) significantly affected total milk yield. MY was significantly lower in the second season
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(June to November) in comparison to MY in the first season (December to May) (by 13.2% from 1652 to 1458 l/lactation; Table 2). The partition of the calving between the two seasons was 87 and 13% for the first and second seasons, respectively. The results of the current study are similar to those reported by Musaad et al. (2013). In consistent with Musaad et al. (2013), the largest persistency in MY, peak of MY were found in she-camels that calved between November to February (Musaad et al., 2013). Lack of heat stress is most likely the most significant factor that explains the higher MY in camels calving between November and February. In consistent with results in dairy cows (Barash et al., 2001) the lack of heat stress is more important than the negative effect of shorter days that are typical to this season on MY. 3.3.1.3. Calf mortality. The mortality rate of calf was 32% in this study (Table 2). The mortality of calf significantly affected total MY. In general, total MY decreased significantly when camel calves died during lactation as compared with those which carried calves until weaning (Table 2). The highest decline in total MY (10%) was obtained when stillbirth occurred, or when calf mortality happened in early lactation (6% at two months of age) in comparison to calves death occurring at later stages (3% between four and six months of age). Mortality percentage of new-born camels was frequently found to be high (50%) in many areas of eastern Africa (Hussein, 1987). The lack of suckling is considered as a major factor, which restrict MY because the suckling stimulation is essential for milk let-down. Thus, high calf mortality is an important constraint to increase productivity in she-camels (present results). Nagy et al. (2013) found if camels are trained to machine milking, calf is not necessary for milking the camels, which suggest that a solution to this problem is available. 3.3.1.4. Lactation period. The length of lactation affected significantly the total MY. Partial regression coefficient between total MY and lactation length was 4.2 l/day. In other words, under the present conditions, when the lactation period increased by one day, the total MY increased by 4.2 l. 3.3.2. Factors affecting milk composition 3.3.2.1. Parity. The lactation number affected significantly milk TP, ash and MF contents, while, there were no significant effect of lactation number on TS and ML. Advance in lactation number was associated with decline in most milk components. First lactation was characterized with high contents of TP, MF, ML and TS (3.29, 3.70, 3.95 and 10.65% in average, respectively). The seventh lactation was characterized with low contents of TP, MF, ML and TS (2.27, 2.71, 3.80 and 10.12% in average, respectively). Ash content increased with advancing of the lactation number; however, the lowest value of ash content was recorded at the first lactation while the highest level was at the seventh lactation (Table 3). The results of this study in fat are consistent with those of Aljumaah et al. (2012).
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Table 3 Least-square means and their standard error for parity, calf mortality, calving month and lactation month and their effect on milk components of she-camels. Factors
No. of records
Total solids %
Protein %
Fat %
Ash %
Lactose %
Parity 1 2 7
70 10 20
10.65a ± 0.4 10.51a ± 0.7 10.12a ± 0.6
3.29a ± 0.1 2.41b ± 0.1 2.27c ± 0.1
3.70a ± 0.2 3.03ab ± 0.3 2.71b ± 0.3
0.65a ± 0.02 0.75b ± 0.04 0.91c ± 0.04
3.95a ± 0.3 3.81a ± 0.6 3.80a ± 0.5
Calf mortality Dead Live
10 90
9.9a ± 0.6 10.9a ± 0.3
2.63a ± 0.1 2.68a ± 0.1
3.14a ± 0.3 3.15a ± 0.1
0.79a ± 0.04 0.75a ± 0.02
3.4a ± 0.5 4.2a ± 0.2
Calving month January February March April
20 40 10 30
10.36a 10.79a 10.48a 10.07a
± ± ± ±
0.4 0.4 0.7 0.6
3.20a 2.45b 2.50c 2.49cd
± ± ± ±
0.1 0.1 0.1 0.1
Lactation month 1 2 3 4 5 6 7 8 9 10
10 10 10 10 10 10 10 10 10 10
11.71 10.51 11.22 9.78 9.34 10.37 9.32 9.91 10.57 11.52
± ± ± ± ± ± ± ± ± ±
0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5
3.00 2.76 2.80 2.49 2.33 2.45 2.40 2.48 2.76 3.08
± ± ± ± ± ± ± ± ± ±
0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07
Mean
11.06 ± 0.1
3.01 ± 0.02
2.33a 3.35bd 3.57bc 3.35cd
± ± ± ±
0.3 0.2 0.3 0.2
3.64 3.24 3.08 2.62 2.54 2.88 3.10 3.29 3.32 3.75
± ± ± ± ± ± ± ± ± ±
0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22
3.06 ± 0.05
0.77a 0.79bc 0.83c 0.69d
± ± ± ±
0.04 0.02 0.04 0.03
3.92a 4.01a 3.76a 3.73a
± ± ± ±
0.3 0.4 0.6 0.5
0.75 0.75 0.72 0.73 0.74 0.74 0.77 0.81 0.84 0.84
± ± ± ± ± ± ± ± ± ±
0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03
4.30 4.13 4.43 3.92 3.70 4.05 3.28 3.29 3.64 3.82
± ± ± ± ± ± ± ± ± ±
0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4
0.69 ± 0.01
4.33 ± 0.1
The means in a column with a similar superscript are not significantly different (P > 0.05).
3.3.2.2. Calf mortality. The effect of calf mortality on milk composition was not significant. 3.3.2.3. Calving month. The month of calving affected significantly milk TP, MF and ash contents, while, the contents of TS and ML were not affected. TS and ML contents were the highest in February; while the lowest values were recorded in April (Table 3). Milk TP content was the highest in January while the lowest value was observed in February. The highest value of MF content was observed in March while the lowest value was recorded in January. The present results are similar to that reported by Haddadin et al. (2008). Whereas, Abdoun et al. (2007) noted that MF content was highest (P < 0.01) in hot summer and decreased significantly during both winter and rainy seasons. 3.3.2.4. Lactation month. Lactation month affected significantly milk TP, MF, ash and TS while ML content was not affected. The values of MF, TP and TS were higher during the first stage of lactation (Early-lactation) as compared to the second one (Mid-lactation) (from 3.00, 3.64 and 11.71%, respectively, at the first month of lactation to 2.33, 2.54 and 9.34%, respectively, at the fifth month of lactation (Table 3). At the last stage of lactation (Late-lactation), the values of MF, TP and TS gradually increased to similar levels to those recorded at the first stage of lactation (Early-lactation). Milk TP, MF and TS gradually decreased during the first stage of lactation. Ash content increased significantly with the progress of the lactation from 0.75% at the first month of lactation to 0.84% at the last month of lactation (10th month). ML content varied from 3.28 to 4.43% (mean, 3.86%). The current
results are consistent with previous reports (Alshaikh and Salah, 1994; Gaili et al., 2000; Zeleke, 2007; Aljumaah et al., 2012). 3.3.2.5. Milk yield. Milk yield was significantly associated with milk TP and ash contents while TS, fat and ML contents were not affected by MY. Partial regression coefficient of TS, TP, MF, ash and ML on total milk yield was 0.001 ± 0.007, 0.0003 ± 0.0001, 0.0004 ± 0.0003, 0.0001 ± 0.0002 and 0.00008 ± 0.00006%/l, respectively. In other words, when the milk yield increases by 1 l, the concentration of TS, TP, MF, ash and ML were also increased by the mentioned values. 4. Conclusion Our results can contribute for increasing the efficiency of raising she-camels for milk in desert areas by adjusting the nutrition to the lactation pattern and milk yield. The wide range of milk yield of Maghrebi she-camel indicates the high potential of long-term selection programs to select for high milk yield by this breed. In turn, increasing milk yield will contribute to increase food security in areas vulnerable for food shortage. Conflict of interest None. References Abdoun, K.A., Amin, A.S., Abdelatif, A.M., 2007. Milk composition of dromedary camels (Camelus dromedarius): nutritional effects and
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Please cite this article in press as: Abdalla, E.B., et al., Milk production potential in Maghrebi she-camels. Small Ruminant Res. (2014), http://dx.doi.org/10.1016/j.smallrumres.2014.11.004