Urea and/or cottonseed meal supplements to Rhodes grass hay improve productivity of periparturient crossbred Boer goat does

A Aoetpah^1,2, A J Parker^1,3, B Gummow^1,4, C Gardiner¹, A Mialone¹ and G Walker¹

¹ College of Public Health Medical and Veterinary Sciences, James Cook University, P O Box 4811, Townsville, Australia
aoetpah@yahoo.com
² Department of Animal Husbandry, State Agricultural Polytechnic of Kupang, P O Box 1152, Kupang, Indonesia
³ Meat and Livestock Australia, P O Box 1961, North Sydney, NSW, Australia
⁴ Faculty of Veterinary Science, Department of Production Animals, University of Pretoria, P O Box 0028, South Africa

Abstract

Periparturient meat goats grazing on low-quality tropical pasture could experienced pregnancy toxaemia. Protein supplementation was expected to enhance the goats’ productivity. This study sought to limit loss of live weight (LW) and to prevent metabolic disorders in periparturient crossbred Boer does. Twelve pregnant does (LW 62.2 +/- 6.30 kg, mean +/-sem) were allocated to treatment groups; Rhodes grass (Chloris gayana) hay as control (CON) or CON supplemented with non protein nitrogen as urea (U), protein nitrogen as cottonseed meal (CSM) or urea plus cottonseed meal (UCSM). The supplemented diets were isonitrogenous (crude protein 143 g/kg DM) with varied undegradable and rumen degradable protein. The does had ad libitum access to the basal diet, fresh drinking water and mineral lick. The fixed effects of dietary treatment and physiological period were tested at the p<0.05 threshold. Both the UCSM and CSM supplements increased intakes of DM, protein fractions and metabolizable energy in the does. Despite the higher DMI there were no impacts on LW loss in lactating does. Supplementation with UCSM reduced plasma non-esterified fatty acids and beta-hydroxy butyrate by 0.14 and 0.28 mmol/L by comparison with those on the Con diet. Plasma concentrations of urea of the does were increased by 42.5 (U); 35 (UCSM) and 12.5% (CSM) above that for the Con group. The dietary nitrogen supplements offered to the periparturient goats on tropical grass hay prevented metabolic disorders of the does. Our findings revealed that periparturient Boer does on Rhodes grass hay were well nourished when the does were supplemented with UCSM.

Keywords: blood metabolites, body weight, dietary nitrogen, meat goats

Introduction

Tropical grasses are typically the main basal diet for ruminants including meat goats, but the nutritional quality is not uniform year round. For example, Rhodes grass (Chloris gayana) has a linear decrease in crude protein (CP), but a linear increase in neutral detergent fibre and lignin from young immature to mature growth stages (Mbwile and Uden 1997). Mature Rhodes grass hay therefore, has insufficient metabolizable protein and energy contents to meet the nutritional requirements of periparturient Boer does (NRC 2007). Consequently, the does could experience metabolic disorders (Vasava et al 2016) and lose weight (Raats 1988).

Supplementation of a basal diet of mature tropical grass with energy and/or protein has been found to enhance the productivity of periparturient does. For example, Raats (1988) reduced LW loss from 9.9 to 4.4 kg of lactating Boer does browsing on paddocks by offering the does 760 g of mixed corn meal and commercial premix (198 g CP/kg DM). Greyling et al (2004) supplemented 2 kg/d of a pelleted diet (140 g CP/kg DM) to lactating Boer does grazing on pasture (67 g CP/kg DM) and reported that LW loss of the does was reduced. Less LW losses in these studies suggests that tissue mobilisation of nutrient reserves from the body could help prevent metabolic disorders.

There is evidence that the ratio of rumen degradable protein (RDP) to undegradable dietary protein (UDP) may be important for optimising performance Boer does as meat goats. The ratios between RDP and UDP for pregnant and lactating dairy goats (Alves et al 2013; Brun-Bellut et al 1990; Laudadio and Tufarelli 2010) have been reported. Among the common supplements, urea is an NPN-RDP source while sunflower meal, soybean meal, cottonseed meal and corn gluten meal are mostly true dietary protein RDP and UDP sources (NRC 2007). The inclusion of these protein sources in supplementary diets will vary the relative amount of UDP and RDP, even when the diet is isonitrogenous.

Studies on lactating dairy goats showed that supplementation with urea and other protein sources elicited similar DM intake. Alves et al (2013) found that lactating dairy goats fed coast-cross hay with soybean meal, urea plus soybean meal, or urea plus cottonseed meal (147, 145, and 141 g CP/kg DM) had similar DM intake. Laudadio and Tufarelli (2010) fed lactating dairy does with 2 isonitrogenous total mixed rations (175 g CP/kg DM); a high RDP diet containing urea, soybean meal and sunflower meal and a low RDP diet containing corn gluten meal and found similar DM intake for both diets. Studies on lactating dairy goats (Brun-Bellut et al 1990; Alves et al 2013; Laudadio and Tufarelli 2010) reveal that DM intake was not only dependent on dietary CP concentration, but also on the relative amount of dietary RDP and UDP.

We hypothesise that urea as a source of NPN-RDP and cottonseed meal as a source of RDP and UDP or the mixture of urea and cottonseed meal will elicit different productive and physiological responses in periparturient meat goats despite the diets being isonitrogenous. Therefore, the main objectives of this study was to investigate if dietary crude protein supplementation at levels up to 143 g/kg DM can limit LW loss and potentially prevent metabolic disorders (ketosis) in periparturient crossbred Boer does by varying the quantity of UDP and RDP.

Materials and methods

Animal ethics

The study was approved by the Animal Ethics Committee of James Cook University (Approval Number A2085). The experiments followed the guidelines and regulations of the 2013 Australian Code of Practice for the Care and Use of Animals for Scientific Purposes.

Experimental animals

This study was conducted in the experimental animal shed at James Cook University, Townsville, (19^o19’30’’ S; 146^o45’44’’ E), North Queensland, Australia, from August to October 2014. Twelve adult crossbred goat does (Australian wild goats X Boer) with a mean LW of 62.2 +/- 6.3 kg) which had been mated to a Boer bucks were penned individually for a minimum of 14 d prepartum and a minimum of 14 d postpartum.

The health condition of the animals was assessed for internal parasites using faecal egg count (Hutchinson 2009), Famacha score and packed cell volume. Two g of fresh faeces per doe was collected for worm egg counts before the experiment commenced and infected does with more than 500 eggs per count (Love and Hutchinson 2007) were dewormed with Zolvix monepantel at 1 mL/10 kg body weight. This was repeated a week later to ensure all does were free from internal parasites. The Famacha scoring system was also applied and the results showed that the does were not suffering from anaemia because the Famacha scores were between the normal value of 1 and 2 (Glaji et al 2014). Ten mL of blood was drawn from the jugular vein to determine packed cell volume and the values of 25 to 30% confirmed that the does were not anaemic or dehydrated.

Experimental procedure

A randomised experimental design with 4 dietary treatments and 3 replicates (4 x 3 = 12 experimental units) was utilised for this study. The does were allocated to Treatment groups based on LW and condition score, so that mean LW for goats in each group was similar. The diets comprised Rhodes grass hay (RGH), flaked corn as an energy source, urea as an NPN-RDP source and cottonseed meal as an RDP and UDP mostly true protein source. The 4 dietary treatments were RGH plus corn as Control diet (CON) or Control plus urea (U) or urea mixed cottonseed meal (UCSM) or cottonseed meal (CSM).

Rhodes grass hay was chaffed (SFC 2340 ‘Star’, machinery chaff, Jas Smith, Ballarat, Australia) into lengths of 5 – 10 cm and stored. The ad libitum RGH offered was adjusted daily based on one and a half of RGH intake over 2 previous days allowing for refusals. Proportions of steamed flaked corn for the CON, U, UCSM and CSM treatments were 40, 41, 40 and 39 g/kg DM, respectively. For the U and UCSM treatments, the urea solution (3 : 10, w/w) in clean tap water was prepared and manually mixed into the hay before morning feeding. Urea proportions for U and UCSM treatments were 10 and 5 g/kg DM, respectively. Cottonseed meal was mixed thoroughly with RGH at 30 and 56 g/kg DM for the UCSM and CSM treatments, respectively. Mineral licks (Rumevite^® Fermafos) were provided in a small separate bucket for each doe and fresh clean drinking water was offered ad libitum.

Diet formulation and feeding regime

The diets were formulated to be isocaloric and isonitrogenous in their relative amounts of dietary UDP and RDP. Dietary CP concentration for the CON group was 107 g/kg DM. Dietary CP concentrations for the supplemented groups were adjusted to 143 g/kg DM as this concentration was expected to support optimum production (Satter and Slyter 1974). Nutrient compositions of the experimental diets are presented in Table 1.

Laboratory analysis for dry matter (DM), organic matter (OM) and crude protein (CP) were carried out at James Cook University, Australia. Some 10% of feed offered and feed refused was collected daily, placed in airtight sealed plastic bags and stored at 3^oC. At the end of the study another sample (10%) was obtained. The samples were oven dried at 60^oC, ground to pass through 1 mm sieve and analysed for DM, OM and CP as described by the AOAC (1990). Feeds allocations were offered as equal portions at 08:00 and 16:00 hours daily. Feed intake was calculated as the amount of feed offered minus that refused within 24 h for each doe. Similar calculation was computed for DM intake. Intakes of protein fractions and energy were on dry matter basis. The proportions of RDP, UDP and the metabolizable energy (ME) content of the RGH were those reported by SCA (1990), and for urea and CSM the values reported by NRC (2007) were adopted.

Measurement of live weight and blood plasma metabolites

Live weights of does were recorded 6-26 days before parturition, immediately after, then at 15 days after parturition. Approximately 10 mL of blood were drawn from the jugular vein of each doe 2 to 4 h after the morning feed allocation using a vacutainer and needle (20 g x 1.5”) into 2 heparin containing tubes (LH 170 IU, Belliver Industrial Estate, UK) every 2 days. The tubes were then centrifuged (Eppendorf centrifuge 5702 R, Hamburg, Germany) at 3^oC and 3000 rpm for 20 minutes to harvest 5 mL of plasma, stored in duplicate plastic vials and frozen at -21^oC, pending analysis. The concentrations of non-esterified fatty acids (NEFA), β-hydroxybutyrate (BHB), total protein (TP) and plasma urea were analysed using Randox reagents and a commercial test kit (Randox, Australia, www.randox.com/powerline) at James Cook University, Townsville, Australia.

Statistical analysis

Statistical analyses were conducted in 2 separate phases in which the effect of treatment on body weight changes, was tested using One-way ANOVA; while a General Linear Model procedure was used to fit the fixed effects of dietary treatment and period of measurement and their second order interactions on plasma metabolites and feed intake (SPSS, version 23.0, IBM Corp, NY, USA 2014). Dietary fixed factors were CON, U, UCSM and CSM. Periodical fixed factors for intake were pregnancy and lactation. Periodical fixed factors for blood metabolites were later pregnant, d1–d4 postpartum and d5–d10 postpartum. If there were differences between these factors at P< 0.05, then the Post hoc Duncan multiple range test was employed.

Results

Intakes of dry matter, protein fractions and metabolizable energy

Intakes of DM, protein fractions and ME of the does 14 days pre- and post-partum are presented in Table 2. It is clear that DM intake was increased (p<0.05) by supplementation with UCSM and CSM during both pregnancy and lactation. During pregnancy, no increase in intakes of CP and RDP for U does could be shown (p>0.05) and increased significantly (p<0.05) for the does fed the UCSM and CSM supplements. No significant (P>0.05) changes were measured for the intakes of ME and UDP during pregnancy for the does fed the U supplement but significant increases (p<0.05) in the intakes of ME and UDP were measured for the does fed the UCSM and CSM supplement. In the lactating does similar changes were recorded with the intake of RDP being significantly increased (P<0.05) in the does fed the U supplement.

Intakes of DM, protein fractions and ME were higher during lactation than during late pregnancy, but the differences were not significant (p>0.05). It was also evident that there was no interaction between period and dietary treatment in affecting intakes of DM, protein fractions and ME of the does.

Live weight changes

Live weight changes over the first two weeks of lactation of the does were not affected by supplementation with NPN and/or PN as shown in Table 3.

Protein supplementation had no significant effect on liveweight changes of periparturient Boer goats.

Blood plasma metabolites

Concentrations of plasma components are presented in Table 4. The dietary supplement had a significant effect but no significant (p>0.05) changes were measured between late pregnancy, days 1-4 and days 5-10 after parturition. Similarly there were no significant (p>0.05) diet x period effects on the plasma components measured. Plasma NEFA were significantly higher (p<0.05) for does supplemented with U than UCSM, with differences for does fed the CON and other supplemented diets not being significant (p>0.05). Concentration of BHB in plasma of does fed the control diet and the diet supplemented with U were significantly higher (p<0.05) than for the does supplemented with UCSM or CSM.

Plasma total protein was significantly lower (p<0.05) for does fed the diet supplemented with CSM compared to the other 3 diets. Plasma U was significantly (p<0.05) lower for the does fed the CON compared to all other diets and significantly higher (p<0.05) for does fed the diet supplemented with U compared to the diet supplemented with CSM.

Discussion

Intakes of dry matter, protein fractions

During late pregnancy the intake of DM was lower for the does fed the diet supplemented with U than for the other diets and in particular the diets supplemented with UCSM and CSM. This may have been caused by the bitter taste of urea, which has been reported to depress feed intake in ruminants (Tadele and Amha 2015). The higher plasma concentration of urea in does fed the diet supplemented with U may have possibly triggered a negative feedback leading to reduce feed intake as suggested by Provenza (1995).

Although the intakes of DM, protein fractions and ME were not significantly different (p>0.05) between late pregnancy and lactation there was a trend for all intakes to increase during lactation, possibly because of increased space within the abdomen after parturition as suggested by McDonald et al (2011). Another factor possibly leading to increase intakes might have been the metabolic adjustments which occur to meet the requirements for specific nutrients as suggested by Bell (1995). When these nutrient requirements are not met, a metabolic adaptation takes place in the form of gluconeogenesis in the liver and changes in the synthesis and catabolism of amino acids and usage of fat for energy (Bell 1995).

Changes in live weight

The does in all 4 groups lost LW during the first 2 weeks of lactation with LW for all groups falling within the range of 52 to 57 kg as reported by Van Niekerk and Casey (1988) for Boer does. Loss of LW would be consistent with intakes of ME and protein fractions being inadequate to meet the requirements of the does possibly due to the adjustments in intakes of key nutrients which occur during the early post-partum period (McDonald et al 2011). Mobilisation of nutrients from body reserves occurs to meet the deficiencies in dietary intakes. It is acknowledged that the proportion of nutrients ingested, which are utilised for maintenance or other functions in the does, would have varied depending on the number of foetuses. The data for LW changes of the pregnant does and for total weights provides a meaningful indication of the performance of the does.

Blood plasma metabolites

Overall, the concentrations of plasma constituents measured were consistent with the does in the present study being well nourished. The increase in plasma NEFA in the does supplemented with urea and the decrease in the does fed the UCSM supplement is consistent with the report of Celi et al (2008) that there is a negative relationship between ME intake and plasma NEFA. In no instance was plasma NEFA increased to pregnancy toxaemia levels of 1.67 mmol/L reported by Vasava et al (2016) to be indicative of pregnancy toxaemia in the goat.

The increased BHB in plasma of the goats fed the CON diet and the diet supplemented with U were consistent with the lower intakes of DM and ME in these groups compared to those supplemented with UCSM and CSM. Similar increases in BHB with lowered intakes of ME have been reported in dairy goats (Bronzo et al 2010; Sahlu et al 1995). The increased BHB would be consistent with the oxidation of mobilised body lipid. Notwithstanding, none of the goats had plasma BHB concentrations reported for goats with pregnancy toxaemia (Vasava et al 2016).

The decreased plasma TP in the does supplemented with CSM cannot be explained and certainly is in conflict with the report of Sahlu et al (1992) that plasma TP in Angora goats is dependent on protein intake from the diet. Plasma TP concentrations for all groups of goats throughout the study were similar to the values of 60–78 g/L reported for healthy goats by others (Hefnawy et al 2010; Komala et al 2011; Samira et al 2016) and well above the concentration of 31.9 g/L for goats with pregnancy toxaemia reported by Hefnawy et al (2011). The higher plasma urea concentrations for the does supplemented with dietary NPN/PN, and in particular those supplemented with U and UCSM, are consistent with previous observations reported for dairy goats (Sahlu et al 1995; Barbosa et al 2012) and conform with the detoxification of excess blood ammonia by the synthesis of urea for excretion in urine and/or recycling via the gastrointestinal tract (McDonald et al 2011).

Conclusion

The dietary nitrogen supplements of urea and or cottonseeed meal offered to the periparturient goats on Rhodes grass as a tropical grass hay prevented metabolic disorders of the does. Our findings revealed that periparturient Boer does on Rhodes grass hay were well nourished when the does were supplemented with UCSM

Acknowledgements

The authors gratefully acknowledge the Australian Awards PhD scholarship funding for the first-named author from the Australian Government’s Department of Foreign Affairs and Trade Agency for International Development (AusAID). Financial (DBA Funds) and technical support was received from James Cook University, Australia. The authors thank Dr Aduli Malau-Aduli’s for his editorial comments and suggestions for improving the quality of this manuscript.

Conflict of interest

The authors verify that they do not have any competing of interest.

References

Alves A R, de Medeiros A N, de Oliveira J S, Costa G C, Costa M G, do Egypto Queiroga R, de Souza D L 2013 Soybean meal or cotton by-products associated with urea as source of nitrogen in lactating goats. Revista Brasileira de Zootecnia. 4, pp.264-272. https://www. scielo.br/j/rbz/a/8JwYRc3fs7KSDpyWqwbBPXp/?format=pdf&lang=en

AOAC (Association of Official Analytical Chemists) 1990. Official methods of analysis. 15^th edition. pp. 69-88. Virginia, USA. https://www.researchgate.net/publication/292783906_AOAC_1990/link/56b12d5d08ae795dd5c4f7f1/download?_tp=eyJjb250ZXh0Ijp7ImZpcnN0UGFnZSI6InB1YmxpY2F0aW9uIiwicGFnZSI6InB1YmxpY2F0aW9uIn19

Barbosa J G, Costa R G, De Medeiros A N, Queiroga R C R, Batista A M V, de Medeiros G R, Filho E M B 2012 . Use of different urea levels in the feeding of Alpine goats. Revista Brasileira de Zootecnia. 41, pp.1713-1719. https://www.scielo.br/j/rbz/a/vsmNyhT8scS48sbvmtMpShk/?format=pdf&lang=en

Bell A W 1995 Regulation of organic nutrient metabolism during transition from late pregnancy to early lactation. Journal of Animal Science.73, pp.2804-2819. https://www.webpages.uidaho.edu/ruminant_nutrition/Reading%20materials%20511/Nutrient%20metabolism / Regulation of Organic Nutrient Metabolism During Transition from Late Pregnancy to Early Lactation (uidaho.edu)

Bronzo V, Puricelli M, Agazzi A, Invernizzi G, Ferroni M, Moroni P, Savoini G 2010 Effects of protected fish oil in the diet of periparturient dairy goats on phenotypic variation in blood and milk leukocytes. Animal. 9, pp.1510-1517. https://pdf.sciencedirectassets.com/778414/1-s2.0-S1751731110X70434/1-s2.0-S1751731110000522/main.pdf

Brun-Bellut J, Blanchart G, Vignon B 1990 Effects of rumen-degradable protein concentration in diets on digestion, nitrogen utilization and milk yield by dairy goats. Small Ruminant Research. 3, pp.575-581. https://cdnsciencepub.com/doi/pdf/10.4141/cjas91-133

Celi P, Di Trana A, Quaranta A 2008 Metabolic profile and oxidative status in goats during the peripartum period. Australian Journal of Experimental Agriculture . 48, pp.1004-1008. https://www.researchgate.net/publication/248891912

Glaji Y A, Mani A U, Bukar M M, Igbokwe I O 2014 Reliability of FAMCHA^© chart for the evaluationof anaemia in goats in and around Maiduguri. Sokoto Journal of Veterinary Science 12, pp.9-14. http://dx.doi.org/10.4314/sokjvs.v12i3.2

Greyling J P C, Mmbengwa V M, Schwalbach L M J, Muller T 2004 Comparative milk production potential of Indigenous and Boer goats under two feeding systems in South Africa. Small Ruminant Research 55, pp.97-105. https://www.sciencedirect.com/science/article/abs/pii/S0921448803003845

Hefnawy A E, Shousha S, Youssef S 2011 Hematobiochemical profile of pregnant and experimentally pregnancy toxemic goats. Journal of Basic and Applied Chemistry. 1(8), pp.65-69. https://www.researchgate.net/publication/266970745

Hefnawy A E, Youssef S, Shousha S 2010 Some immunohormonal changes in experimentally pregnant toxemic goats. Veterinary Medicine International. 20, pp.1-5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2896860/pdf/VMI2010-768438.pdf

Hutchinson G W 2009 Nematode parasites of small ruminants, camelids and cattle. Diagnosis with emphasis on Anthelmintic efficacy and resistance testing. Australia and New Zealand Diagnostic procedures. https://www.agriculture.gov.au/sites/default/files/sitecollectiondocuments/animal/ahl/ANZSDP-Nematode-parasites-ruminants.pdf

Komala T S, Mahadi Y, Khairunnisak M, Ramlan M 2011 Studies on nutritionally-related blood metabolites - total protein and glucose levels, in goats of Kinta and Hilir Perak districts. Malaysian Journal of Veterinary Research . 2, pp.9-16. https://myjurnal.mohe.gov.my/filebank/published_article/24719/2.pdf

Laudadio V, Tufarelli V 2010 Effects of pelleted total mixed rations with different rumen degradable protein on milk yield and composition of Jonica dairy goat. Small Ruminant Research 90, pp.47-52. https://www.sciencedirect.com/science/article/abs/pii/S0921448809003162

Love S, Hutchinson G 2007 Worm test for livestock and guide to egg counts. Prime Fact 480, New South Wales Department of Primary Industry. https://www.dpi.nsw.gov.au/_data/assets/pdf_file/0016/110077//wormtest-for-livestock-and-guide-to-egg-counts.pdf

Mbwile R P, Uden P 1997 Effect of age and season on growth and nutritive value of Rhodes grass ( Chloris gayana cv. Kunth). Animal Feed Science and Technology 65, pp.87-98. https://doi.org/10.1016/S0377-8401(96)01085-1

McDonald P, Edwards R A, Greenhalgh J F D, Morgan C A, Sinclair L A, Wilkinson R G 2011 ‘Animal nutrition.’ (Seventh edn, Prentice Hall: Britain)

NRC (National Research Council) 2007 ‘Nutrient requirements of small ruminants sheep, goats, cervids, and new world camelids.’ (The National Academies Press: Washington, D.C)

Provenza F D 1995 Postingestive feedback as an elementary determinant of food preference and intake in ruminants. Journal of Range Management 48, pp.2-17. https://repository.arizona.edu/bitstream/handle/10150/644441/8983-8864-1-PB.pdf Raats J G 1988 The effect of supplementation on milk yield in Boer goat ewes. South African Journal of Animal Science18, pp.97-100. https://www.sasas.co.za/journals/the-effect-of-supplementation-on-milk-yield-in-boer-goat-ewes/

Sahlu T, Fernandez J M, Lu C D, Manning R 1992 Dietary protein level and ruminal degradability for Mohair production in Angora goats. Journal of Animal Science 70, pp.1526-1533. http://jas.fass.org/content/70/5/1526

Sahlu T, Hart S P, Le-Trong T, Jia Z, Dawson L, Gipson T, Teh T H 1995 Influence of prepartum protein and energy concentrations for dairy goats during pregnancy and early lactation. Journal of Dairy Science 78, pp.378-387. https://www.journalofdairyscience.org/article/S0022-0302(95)76646-2/pdf

Samira A M, Mohammed A R, Anaam E O, Sheeba A, Waleed M A 2016 Biochemical and hematological profile of different breeds of goats maintained under intensive production system. African Journal of Biotechnology . 15, pp.1253-1257. https://www.ajol.info/index.php/ajb/article/view/140549

Satter L D, Slyter L L 1974 Effect of ammonia concentration of rumen microbial protein production in-vitro. British Journal of Nutrition 32, pp.199-208. https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/effect-of-ammonia-concentration-on-rumen-microbial-protein-production-in-vitro

SCA (Standing Committee on Agriculture) 1990 ‘Feeding standard for Australian livestock, ruminants.’ (CSIRO, Melbourne: Australia) https://books.google.co.id/books/about/Feeding_Standards-for_Australian_Livesto.html ?

Tadele Y, Amha N 2015 Use of different non-protein nitrogen sources in ruminant

nutrition: A review. International Journal for Advances in Life Science and Technology . 29, pp.100-105. https://core.ac.uk/download/pdf/234687103.pdf

Van Niekerk W A, Casey N H 1988 The Boer goat. II. Growth, nutrient requirements,carcass and meat quality. Small Ruminant Research . 1, pp.355-368. https://cgspace.cgiar.org/items/ff0023e1-885b-47a3-a528-d1c59b6a35b6

Vasava P R, Jani R G, Goswami H V, Rathwa S D, Tandel F B 2016 Studies on clinical signs and biochemical alteration in pregnancy toxemic goats. Veterinary World. 9, 869-874. https://www.veterinaryworld.org/Vol.9/August-2016/12.pdf