Effects of supplementation, birth type, age and stage of lactation on milk yield and composition of Norwegian x Small East African goats in Morogoro, Tanzania

Introduction

The major problem facing children in developing countries is protein-energy malnutrition (Khalid 2013). This is because the majority of children in developing countries do not consume adequate amount of animal protein e.g. milk, which is rich in easily digestible proteins, calcium, phosphorus and vitamins (Morand-Fehr et al 2007). Dairy goats play an important role in converting crop residues into valuable products i.e. meat and milk which has special value in human nutrition in households which cannot afford keeping dairy cows (Soryal et al 2004). In addition, dairy goats are efficient in feed utilization and they can adapt to a wide range of environments, high temperatures and underfeeding (Boyazoglu et al 2005).

Small East African goats are a very important goat breed in Tanzania although it is known to have low milk yields (0.67litre/day), high total solids (16.2%) and milk fat (6.95%) compared to the improved dairy goats (Kurwijila et al 1985). For example Norwegian dairy goats were observed to have average milk yield of 1.43 litres/day, with 3.65% fat and total solids of 11.3% (Kurwijila et al 1985).  Introduction of Norwegian dairy goats in Tanzania and crossbreeding programs to increase the Norwegian blood in order to have the gene combination from the two (survivability and milk production) are key strategies for improving milk production from goats in Tanzania (Mtenga et al 1985).

Milk yield and composition from dairy goat can be improved through proper feeding, good management, breeding and disease control. For example a study by Gillah et al (2014) reported higher average milk yield in dairy cows supplemented with a well formulated concentrate during pre-partum and post-partum compared to the cows supplemented with maize bran only post-partum.

Optimum feeding systems for dairy goat farmers are very important because they need a balance between the costs of production and the revenue from the dairy enterprise. This is because feeding accounts for 35-50% of total production costs (Sauvant and Morand-Fehr 2000). Feeding strategies that include grazing and concentrate supplementation improve the milk fat, protein, lactose and total solids compared to grazing or forage alone (Soryal et al 2004).

A study by Min et al (2005) reported an increase in milk yield and composition in Alpine does (Capra hircus) at high levels of concentrate supplementation. Information on the effect of feeding on the productivity of Norwegian dairy goats and their crosses is very scarce. Therefore the current study was conducted to assess the effect of different levels of concentrate supplementation on milk yield and composition of Norwegian×Small East African goats at Magadu farm.

Materials and methods

Area of study

The experiment was conducted at Magadu farm belonging to the Department of Animal Science and Production of Sokoine University of Agriculture (SUA), located about 2.5 km South of Morogoro Municipality at the foot of the Uruguru Mountains. Geographically it is located on latitude 4°46´ south and longitude 35°36´ 0 east. The altitude of Magadu farm is 550 m above sea level and it receives about 880 mm of rainfall per annum with temperatures ranging from 27 to 32°C.

Animals and their managements

Forty two (42) lactating does of Norwegian×Small East African goats were randomly allocated into three treatments and supplemented with 200g (treatment C200), 400g (treatment C400) and 600g (treatment C600) of concentrate per day during breeding and pregnancy periods. After kidding the level of concentrate supplementation was gradually increased to 800g of concentrate per day for all goats. The concentrate feed was made up of maize bran (70%), sunflower seed cake (28%) and minerals (2%) (Table 1).

Parameters that were analyzed

Milk yield

Monthly milk yields for each doe were obtained by adding the daily milk yields of four consecutive weeks up to seventh month of lactation.

Milk composition

Milk samples were collected once per month for determination of milk components. BF was determined by Gerber butyrometer method and CP by conventional Kjeldahl method, using the factor 6.38 in converting nitrogen into crude protein (IDF 1986). Total solids were determined gravimetrically ; solids-not-fat were obtained as the difference between total solids and butter fat.

Data analysis

Data collected on monthly milk yield and composition were analyzed by General Linear Models (GLM) procedure of SAS (SAS 2009). The model was:

Y_ijkl = μ +C_i +B_j+ S_k +A_l+ (CS)_ik + e_ijkl

Where Y_ijkl = experimental observation monthly milk yield or milk component, μ = overall mean, C_i = fixed effect of i^th supplementation levels (i =1 = 200g, 2= 400g and 3 = 600g of concentrates, B_j = fixed effect of j^th birth type (j =1 = single, 2 = twins), S_k = fixed effect of k^th stage of lactation (k= 1 = 1, 2, 3, 4, 5, 6, 7 month of lactation), A_l = fixed effect of l^th age class of the doe (l = 1 = 19-22, 2 = 23-25, 3 = 26-28 months), (CS)_ik = fixed effect of interaction between treatment and stage of lactation and e_ijkl = residual error term.

Treatment means were separated by least significant differences when the overall F-values were significant at p<0.05.

Results

Effect of supplementation

 Milk yield was increased by supplementation (Table 2; Figure 1).

Figure 1: Milk yield at different levels of concentrate supplementation during the lactation period

The mean BF, CP, TS and SNF recorded were 3.79%, 3.14%, 16.5% and 11.7%. Increase in the levels of concentrate supplementation led to a significant ( p<0.05) increase in milk composition. Table 2 shows that all milk components increased as the levels of supplementation got higher.

Birth type

Does that kidded single kids produced less milk compared to does that kidded twins (Table 3).  There was no  effect of birth type on CP, TS and SNF, except for BF which was higher (p<0.05) in does that kidded single kids than does that kidded twin kids.

Age of the doe

Milk yield was significantly (p<0.001) affected by age of the does. Milk yield was higher for does in the age class of 26-28 months (41.7 litres/month) compared to does in the age class of 23-25 months (39.77litres/month) and 19-22months (38.36litres/month). CP was significantly (p <0.01) affected by age of does, where does with age class of 23-25 months had milk with higher CP (3.29%) compared to the does with the age of 19-22 months and 26-28 months with crude protein of 3.09% and 3.08% respectively. BF, TS and SNF were not affected by the age of the doe (Table 4).

Stage of lactation

Milk yield was significantly (p<0.001) affected by the stage of lactation. Peak milk production was recorded during the second month of lactation (58.8litres/month). Thereafter milk yield declined to 22.7litres/month during the seventh month of lactation. The trend of milk yield by stage of lactation is presented in Table 5.

 BF was lowest at the second month of lactation when milk yield was at the peak and highest at the first month of lactation (Figure 2). TS was highest in the first month and then declined to third month of lactation as depicted in Figure 2).

Figure 2: Effect of stage of lactation on milk components

Discussion

Supplementation levels

The mean monthly milk yield from the current study is higher compared to that obtained by Kurwijila et al (1985) who reported monthly milk yield to be 29.7litres. This could be due to the different feeding strategies between the two experiments. This study has demonstrated a linear increase in mean monthly milk yields with increase in supplementation. This is in agreement with Min et al (2005) who reported an increase in milk production with increase in the level of supplementation. Furthermore Lefrileux et al (2012) reported higher milk production by does supplemented above 800g/day with concentrates.

The present study has shown that milk components were improved with concentrate supplementation, with highest values among the does supplemented with 600g per day. The increase in BF at higher level of concentrate supplementation agrees with Gewaher et al (2011) who observed higher milk fat in dairy cows in higher level of supplementation. Furthermore, Hart et al (2005) reported higher milk fat (3.2%) and protein (3.12%) for supplemented does compared to those that were not supplemented (3.0% BF and 2.8% CP). However Haenlein (2000) showed that higher levels of concentrate supplementation lowered milk fat especially when the concentrate exceeded the forage in the forage to concentrate ratio. This could be due to sub-clinical ruminal acidosis which lowers the production of acetate and butyrate which are the important precursors for milk fat.

Birth type

The 2.97 litres higher milk yield among does with twin kids is close to results by Milersk (2001) who showed significantly higher milk production for does that kidded twins compared to does with single kids. Furthermore, Bernacka and Siminska (2009) reported that does with multiple kids had higher milk yield compared to does that kidded single kids. Similar results were reported by Ciappesoni et al (2004) who observed a significantly higher average daily milk yield by does that kidded twins compared to the does kidding singles (3.49 vs. 3.59litres/day). Also Dhara et al (2012) reported higher milk yield for does kidded twins and triplets i.e. 0.82 litres/day and 1.32litres per day respectively compared to does that kidded single kids (0.48 litres/day).

Higher milk yield in does kidding multiple kids could be due to the fact that such does have well developed mammary glands during pregnancy period and the suckling of multiple kids induces more milk synthesis from the udder.

The higher milk fat and protein in does that kidded single kids compared to the does that kidded twin kids resemble data reported by Bernacka and Siminska (2009) in which they observed lower milk fat (3.28%) and protein (2.66%) was observed in does that kidded triplet kids than among does that kidded single kids (3.56% fat and 2.76 protein). Likewise Macciota et al (2005) reported higher milk fat in does that kidded singles compared to does kidding twins (5.12% vs. 5.07%). This could be due to the inverse relationship between milk yield and milk fat and protein.

Age of the doe

The increase in milk yield with advancement in age of the doe concurs with the study by Muller (2005) who reported does which kidded at a younger age had lower milk yield compared to those with higher age. Further, Ciappesoni et al (2004) reported a similar increase in milk yield with age of the doe. A study by Eik et al (1991) reported higher milk production for multiparous Norwegian does compared to first fresheners of the same breed (i.e. 2.30 litres/day vs. 1.41 litres/day). This could be due to the increase in body weight which is related to the increase in udder and gastro-intestinal volume both of which are associated with increases in feed intake.

Findings on the effect of age on milk protein concur to studies by Bernacka and Siminska (2009) who concluded that the age of does significantly affected milk protein.

Stage of lactation

Peak milk yield was recorded in the second month of lactation and this agrees with Guler et al (2007) who reported peak milk yield at the second month of lactation and thereafter decreased to the end of lactation. Similarly Haenlein (2000) observed an increase of milk yield up to 50 to 80 days after kidding. Also Agnihotri and Rajkumar (2007) and Norris et al (2011) reported higher milk production in the early weeks of lactation (0.8litres/day) and very little in the late weeks of lactation (0.39 litres/day). Significant influence of stage of lactation on milk composition agrees with Chad et al (2014) who reported a significant variation on milk constituents throughout the stage of lactation in Alpaca (Vicugna pacos).  High BF in early lactation corresponds to Macciota et al (2005) who reported high fat content at early lactation and low fat content in the second month of lactation (4.97%) and increased towards the end of lactation (5.27%). A study in ewes by Sevi et al (2004) showed significant variation of milk composition with the stage of lactation. The high BF (5.13%) and TS (18.9%) at the beginning of lactation compared to the mid and late lactation agrees with Guler et al (2007) who reported higher BF (5.1%) and TS (13.8%) from milk of early weeks of lactation. During late lactation when milk yield was low while protein and fat contents were high. This is because milk yield and fat (also protein) are negatively correlated.

Conclusions

• Milk yield and composition increased with increase in the level of concentrate supplementation.
  
  
• Concentrate supplementation will be economical if the price of milk is high.
  
  
• Does that kidded twins produced more milk compared to those with single kids.
  
  
• As the age of does increased, milk yield also increased.
  
  
• During early lactation, more milk with lower butter fat and crude protein was observed but the opposite was noted in late lactation.
  
  
• Future studies should evaluate the carry-over effect of supplementation on the reproduction performance, weight loss by the doe after kidding and the economics of supplementation.

Acknowledgement

We thank the Programme for Agricultural and Natural Resources for Improved Livelihood (PANTIL) for funding this study. Our thanks are also extended to the members of staff at the Department of Animal Science and Production for their support in analysis of chemical composition of milk and nutritive value of concentrates.

References

Agnihotri M K and Rajkumar V 2007 Effect of parity and stage of lactation on milk composition of western region goats in India. International Journal of Dairy Science 2 (2): 172-177.

Bernacka H and Siminska L 2009 The effects of age and pregnancy type in the coloured enhanced goats on productivity and composition of milk.Journal of Central European Agriculture 10(1):67-72. Retrieved March 23, 2014. From http://jcea.agr.hr/volumes.php?lang=en&search=Article%3A691.

Boyazoglu J, Hatziminaglou I and Morand-Fehr P 2005 The role of the goat in society: Past, present and perspectives for the future. Small Ruminant Research 60(2):13-23.

Chad E K, De Peters E J, Puschner B, Taylor S J and Robison J 2014 Preliminary investigation on the composition of alpaca (Vicugna pacos) milk in California. Small Ruminant Research 117(3):165-168.

Ciappesoni G, Pribyl J, Milersk M and Mares V 2004 Factors affecting goat milk yield and its composition. Czech Journal of Animal Science 49(11):465-473. Retrieved March 26, 2014. From http://www.agriculturejournals.cz/publicFiles/53274.pdf.

Costa R G, Filho E M B, Queirog R C R E, Madruga M S, de Medeiros N and de Oliveira C J B 2010 Chemical composition of milk from goats fed with cactus pear (Opuntia ficus-indica L. Miller) in substitution to corn meal. Small Ruminant Research 94, 214-217. Retrieved on 23 October, 2014 from http://www.sciencedirect.com/science/article/pii/S092144881000235X#

Dhara K C, Ray N, Taraphder S and Guha S 2012 Milk production performance of Black Bengal goats in West Bengal. International Journal of Livestock Production 3(2): 17-20.

Eik L O, Garmo T and Nedkvitne J J 1991 A low cost feeding strategy for Norwegian dairy goats and comparison of performance between first-fresheners and multiparous does. Small Ruminant Research 6 (3):257-265.

Gillah K A, Kifaro G C and Madsen J 2014 Effects of pre partum supplementation on milk yield, reproduction and milk quality of crossbred dairy cows raised in a peri urban farm of Morogoro town Tanzania. Livestock Research for Rural Development. Volume 26, Article #9. Retrieved March 18, 2014, from http://www.lrrd.org/lrrd26/1/gill26009.htm

Gewaher Z, Hassan A, Intesar Y, Turk V, Muna E and Khogali 2011 Effect of concentrate supplementation on milk yield and composition of grazing dairy cows in Southern Kordofan state, Sudan. Research Opinion in Animal and Veterinary Sciences 1(8): 495-498.

Goetsch A L, Zeng S S and Gipson T A 2011 Factors affecting goat milk production and quality. Small Ruminant Research 10(3):55-63.

Guler Z, Keskin M, Masatcioglu T, Gul S and Bicer O 2007 Effect of breed and lactation period on some characteristics and free fatty acid and composition of raw milk from Damascus goats and German fawn×Hair goat B1 crossbreds. Turkish Journal of Veterinary and Animal Science 31(5):347-354.

Haenlein G 2000 Relationship of somatic cell counts in goat milk to mastitis and productivity. 3^rd All Africa Conference on Animal Agriculture and 11 ^th Conference of the Egyptian Society of Animal Production. Alexandria. Egypt.

Hart T, Sutter D I. and Sahlu T 2005 The effects of diets on milk production and on lactation curves in pastured dairy goats. Journal of Dairy Science 88:2606-2615. http://ddr.nal.usda.gov/bitsteam/10113/1987/1/IND43714737.pdf.

IDF (International Dairy federation) 1986 Determination of nitrogen content (kjedahl method) and calculation of crude protein content . International standard. Number 20 A, 3 pp.

Khalid U, Nosheen S, Hussain S, Taran M A, Sadiq S and Ahmad M 2013 Assessment of protein energy malnutrition among children in urban community of Faisalabad, Pakistan. Pakistan Journal of Nutrition 12(4):334-339.

Kurwijila R L, Hansen K K and Ryoba R 1985 Some experiences on goat milk utilization. In: Improved dairy production from cattle and goats in Tanzania. Occasional paper series B (9): 54-62.

Lefrileux Y, Morand-Fehr P and Pommaret A 2012 Capacity of milk yielding goats to utilize cultivated pastures. INRA Animal Production. 25(3):277-290.

Macciota N P P, Fresi P, Usai G and Cappio-Borlino A 2005 Lactation curves of Sarda breed goats estimated with test day models. Journal of Dairy Research 72:470-475.

Milersk M 2001 Analysis of systematic factors affecting milk production in dairy goats. Acta University of Agriculture 1: 43-50.

Min B R, Hart S P, Sahlu T and Satter L D 2005 The effect of diets on milk production and composition, and on lactation curves in pastured dairy goats. Journal of Dairy Science 88:2604-2615.

Morand-Fehr P, Fedele V, Decandia M and Le Frileux Y 2007 Influence of farming system and feeding system on composition and quality of goat and sheep milk. Small Ruminant Research 68(2):20-34.

Mtenga L A, Evjen O H and Eik L O 1985 Improved milk and meat production from goats. In: Improved dairy production from cattle and goats in Tanzania. Occassional paper series B (9):34-45.

Muller C J C 2005 Genetic parameter estimation and breeding plans for the South Africa dairy goat herd. In: Proceedings of the 7th World Congress on Genetics Applied to Livestock Production, August 2005, Montpellier, France, vol. 1, pp. 52–55. http://scholar.sun.ac.za/bitstream/handle/10019.1/1468/Muller,%20C%20J%20C.pdf?sequence=1 .

Norris D, Ngambi J W, Benyi K and Mbajiorgu C A 2011 Milk production of three exotic dairy goat genotypes in Limpopo province, South Africa. Asian Journal of Animal and Veterinary Advances 6: 274-281. http://scialert.net/fulltext/?doi=ajava.2011.274.281&org=10.

SAS (Satistical Analysis System) 2009 User Installation guide for the SAS system version 9.3, SAS institute Inc., Cary. North Calorina, USA 221 pp.

Sauvant D and Morand-Fehr P 2000 Quantitative analysis of dairy goat response to concentrate supplementation. In: Proceedings of seventh International Conference on Goats, Tours, France. pp 80-81.

Sevi A, Albenzio M, Marino R, Santillo A and Muscio A 2004 Effects of lambing season and stage of lactation on ewes milk quality. Small Ruminant Research 5(3):251-259.

Soryal K A, Zeng S S, Min B R and Hart S P 2004 Effect of feeding treatments and lactation stages on composition and organoleptic quality of goat milk Domiati cheese. Small Ruminant Research 52(1): 109-116.

Received 14 July 2014; Accepted 17 November 2014; Published 1 December 2014

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