Protocol for Study: Effect of feeding Moringa oleifera leaves and green stems to dairy cows on milk production and composition

Transcription

1 Balbir Mathur President, Trees for Life 3006 W. St. Louis, Wichita, KS, (316) Protocol for Study: Effect of feeding Moringa oleifera leaves and green stems to dairy cows on milk production and composition This study will examine the effects of Moringa foliage (leaves and green stems) as supplemental forage for dairy cattle on milk production and composition. Experiments will compare the milk production of cows fed only local forage used by small-scale dairy producers with that of cows fed the local forage plus Moringa. Questions to be examined The basic questions to be examined in this study are: What is the composition of the local forage currently used by small-scale dairy farmers? What is the composition of the Moringa forage? How much of the different forages do the cows eat? How much milk is produced when cows eat only the local forage, and when Moringa forage is added as a supplement? What is the composition of the milk produced by cows fed the different diets? What is the effect of the different diets on the weight of the cattle?

2 Study designs Two possible study designs For the experiments in this study, you will use one of two possible study designs: Replicated 3x3 Latin Square Switchback Selecting a study design The main factor to consider in selecting a study design is the lactation curve of the cows. A dairy cow s milk production naturally increases during the early weeks of lactation, until it reaches peak lactation (the highest rate of milk production). Milk production then remains fairly consistent for a number of weeks. Then it begins to slowly decrease until lactation ends. A milk production experiment should be done during the top of the lactation curve. This period starts at peak lactation and lasts until the production rate starts to decrease. During this period, the milk production is fairly consistent. If an experiment is done too early or too late in the lactation curve, the natural changes in lactation level will interfere with the results of the study. Replicated 3x3 Latin Square The Replicated 3x3 Latin Square is the preferred design, as it is statistically stronger. It also requires a small number of experimental animals only 6 cows. And it requires less Moringa fodder to be produced than the Switchback design. However, the Replicated 3x3 Latin Square requires 12 weeks for the experiment, so it should only be used if the lactation curve of the cows allows for a span of 12 weeks during the top of the curve without natural changes in lactation level interfering with the experiment. Switchback If the lactation curve of the cows is too short for a 12-week experiment, then the Switchback design should be used. It only requires a period of 8 weeks for the experiment. Also, in order to do the switchback design, the milk production and composition (milk fat and milk protein) for each cow must be known before the start of the experiment. The switchback design requires more experimental animals 20 cows. And it has a higher requirement of Moringa fodder to be produced. 2

3 Replicated 3x3 Latin Square The replicated 3x3 Latin Square design involves: Six (6) experimental animals (two groups of three cows) Three treatments (diets): A. Local grass forage B. Local grass forage + 2 kg dry matter weight (DM) Moringa* C. Local grass forage + 4 kg DM Moringa Three (3) experimental periods, each consisting of 2 weeks adaptation and 2 weeks data collection Total of twelve (12) weeks for experiment Requires producing 6 kg DM Moringa each day for 12 weeks, for a total of 504 kg DM Moringa o Estimated fresh weights: 18 to 36 kg fresh Moringa per day for 12 weeks, for a total of 1,512 to 3,024 kg fresh Moringa* Table 1: Distribution of treatments (diets) in the replicated 3x3 Latin Square design Group 1 Group 2 Animals Period Cow 1 Cow 2 Cow 3 Period 1 A B C Period 2 B C A Period 3 C A B Animals Period Cow 4 Cow 5 Cow 6 Period 1 A B C Period 2 B C A Period 3 C A B * About Dry Matter (DM) weights The moisture content of forage can differ depending upon soil quality, climate, season and availability of water. So for the sake of uniformity and consistency, all forage measurements are to be done on a dry matter (DM) basis. For instructions on determining DM content of forage, see Dry matter procedure under Guidelines and Procedures below. In these descriptions of the study designs, along with the precise dry matter (DM) weights of forage needed we are also giving estimated fresh weights. These fresh weight estimates are only intended to give an idea of the amount of Moringa foliage that needs to be grown for each study design. Various studies have found the fresh weight of Moringa 3

4 foliage to be from three to six times as much as the DM weight. So we are using these factors for our estimates. When the study is performed, the DM weights of forage are not to be estimated. They are to be determined through actual drying of forage samples to determine the DM content of your forage. Switchback design The Switchback design involves: Twenty (20) experimental animals (2 groups of 10 cows) The milk production and milk composition for each cow must be known before the start of the experiment (see Randomizing animals into two groups below). Two treatments (diets): A. Local grass fodder B. Local grass fodder + 4 kg DM Moringa Two (2) experimental periods, each consisting of 2 weeks adaptation and 2 weeks data collection Total of eight (8) weeks for experiment Requires producing 40 kg DM Moringa per day for 8 weeks, for a total of 2,240 kg DM of Moringa o Estimated fresh weights: 120 to 240 kg fresh Moringa per day for 8 weeks, for a total of 6,720 to 13,440 kg fresh Moringa Table 3: Distribution of treatments (diets) in the Switchback design Animals Period Group 1 (10 cows) Group 2 (10 cows) Period 1 A B Period 2 B A Note: Groups are shown only to indicate distribution of diets. Each cow is to be housed and fed in an individual stall. Randomizing animals into two groups For the Switchback design, the 20 experimental animals need to be randomized into two groups according to their energy corrected milk production: 4

5 1. Calculating energy corrected milk - From the known milk production and milk composition (fat and protein) for each cow, calculate as follows: Energy corrected milk = (0.327 x kg of milk) + (12.95 x kg of milk fat) + (7.2 x kg of milk protein) 2. Pair the animals according to similar energy corrected milk production. 3. From each pair of animals, randomize each cow into one of the two experimental groups. 5

6 Procedures and Guidelines The following procedures and guidelines apply to both study designs. Experimental animals Dairy cows should be selected according to the following criteria: Same breed Same average live weight Similar number of lactations (for example: all heifers in 1 st lactation, or all older cows having had 2 or more lactations) Cows should be starting their peak lactation at the beginning of the experiment Preparation of animals Before the start of the study: Weigh the animals and record their weights Test and treat animals against external and internal parasites, according to needs Give all animals vitamin supplements, according to needs Management of animals Confine the animals in individual, well-ventilated stalls. Each stall should have: Two separate feeding troughs (one for the local grass forage, and one for Moringa) Water ad libitum Mineral salts according to their needs 6

7 Forages Here are some general guidelines for consistency in harvesting and preparation of the forages: Local grass forage Use the type of grass forage that is typically used by small-scale dairy producers in your location. Methods for growing, harvesting and preparation of the grass forage should also be according to local practices. For example, if local grass is usually fed by grazing then feed the grass to cattle as fresh forage. If the grass is usually dried and fed as hay, then follow the local procedure for drying, baling, etc. Moringa Harvest Moringa each evening for feeding the next morning, and each morning for feeding in the afternoon. Chop the Moringa to approximately 2 cm lengths for feeding. Feed Moringa to the cattle after milking. Moringa should not be fed before milking, to avoid transference of any abnormal taste into the milk. Experimental periods Each experimental period is four weeks long. The number of experimental periods depends upon the study design used (see Study designs above). Each period consists of a two-week adaptation phase followed by a two-week data collection phase. Adaptation phase The first two weeks of each period allow the cows time for adaptation to their new diets. During these two weeks, feed the cows their respective diets and milk them on the regular schedules, but do not take any samples or measurements. Data collection phase The third and fourth weeks of each period are for data collection. During these two weeks, samples are taken and data is collected. 7

8 Weighing animals At each of the points during the experiment indicated below, weigh the cows on two consecutive days at similar times of day. For example, you might weigh the cows right after their morning milking on both days. First, weigh the cows and record their weights: On two days at the beginning of the first adaptation phase On the last two days of the first adaptation phase Then, during each experimental period, weigh the cows: On the last two days of the first week of data collection, and On the last two days of the second week of data collection. Milking Cows are to be milked twice daily according to local milking schedules. For example, they might be milked each morning at 06:30 h and each evening at 14:30 h. (Be sure to milk the cows before feeding them Moringa to avoid transference of any abnormal taste into the milk.) Milk sampling and data collection During the data collection phase of each experimental period (third and fourth weeks) measurements are to be taken: Each day, record the total daily milk yield for each cow In each week of data collection, take two milk samples from each cow. These two samples are to be taken at two sequential milking times. (That is, take samples on either a morning and the following evening, or an evening and the following morning). o To take a milk sample for each cow, make sure all of the milk from that cow is thoroughly mixed, and then sampled (as fat content is generally higher at the beginning of a milking). o Mark the samples with the date and time they were taken. o Refrigerate the milk samples for later analyzing. Milk analysis All milk samples are to be analyzed for: Total fat 8

9 Crude protein Total solids Feeding The cows should be given half their daily diets in the mornings and half in the evenings. Make sure the cows are fed after milking. Determining voluntary intake At each feeding time, weigh the local grass forage and the Moringa forage separately before offering each to the cows in separate troughs. Be sure to offer the cows plenty of the local grass forage so they can eat as much as they wish (ad libitum). At the next time for feeding, remove any forage that has not been eaten and weigh the leftover local grass and Moringa separately for each animal. From this procedure you can determine each cow s voluntary intake per day for each type of forage. Forage sampling and data collection During the data collection phase of each experimental period (third and fourth weeks), forage samples are to be taken. Choose one day in each week of data collection to take these samples. On those days, take a sample of the local grass and a sample of the Moringa forage. Freeze these samples for later analysis Composite (mix together) the two local grass samples, and composite the two Moringa samples. You will then have one composite sample of each type of forage per period. Forage analysis All forage samples (local grass and Moringa) are to be analyzed for: Moisture content Dry matter content (DM) see Dry matter procedure below Crude protein (CP) Acid Detergent Fiber (ADF) Neutral Detergent Fiber (NDF) Estimated digestibility of NDF (NDFD) Calcium 9

10 Phosphorous Magnesium Potassium Dry matter procedure When drying wet forages, it is best to use a pre-drying procedure. This procedure avoids any loss of volatiles or binding of proteins to the fiber due to the high temperatures normally used in drying. Pre-drying procedure To pre-dry the forage samples, dry them in a forced air oven at no more than 55º C for at least 48 hours. To check whether the pre-drying is complete, weigh the sample, return it to the oven for 2 hours, and then weigh it again. If there is any change in weight, more pre-drying is required. Drying method After the pre-drying process, complete the drying of the forage samples using one of these methods: 60º C for 4 hours (forced air) 135º C for 2 hours - AOAC º C for 3 hours - NFTA Method Data reporting and analysis When performing the statistical analysis, use the appropriate mixed model for a Replicated Latin Square or Switchback design, depending upon the study design used. All raw data will also be provided to Trees for Life. Publication Research institutions performing these studies are strongly encouraged to seek publication of their work in the scientific journal(s) of their choice. They are also encouraged to seek media exposure of their work. Trees for Life would be glad to help in facilitating media exposure. Trees for Life plans to reference these studies for the purposes of promotion and education. If the studies show that Moringa can significantly increase milk production for small-scale farmers, we will make the results practical and available to farmers at the grassroots level. 10

11 Institution requirements To be considered for these studies, institutions will need to have the following facilities and/or capabilities: Dairy cattle Cattle to suit the study design Facilities for individual housing and feeding Tie stalls or a stanchion barn Two feeding troughs in each stall one for the local grass forage, and one for Moringa forage Assurance that animals are in good health Examination and/or treatment for internal and external parasites Supplemental vitamins and minerals, as needed Measurements and analysis Scales for weighing experimental animals Accurate scales for weighing forages and milk Milk composition analysis Forage composition analysis Drying oven for forage DM analysis Facilities to grow and harvest Moringa Land suitable for agricultural production about a quarter hectare Facilities for irrigating and fertilizing Trees for Life will provide a protocol for growing and harvesting of Moringa. 11

12 Budget The following items are to be included in the itemized budget for this research project: 1. Moringa: Preparing the land Cost of seeds Cost of planting Cost of fertilizers, irrigation, and any other soil ammendments Labor for maintenance of the crop Labor for harvesting and chopping 2. Daily animal use charges: Caring for animals Collecting data Weighing Feeding Manure removal and stall cleaning 3. Labor: Specialized sampling: milk samples, feed samples Handling of data, making reports Body weights 4. Analysis: Forage samples Milk samples 5. Supplies: Consumables (i.e. sample vials, etc.) 6. Publication 7. Statistical analysis 8. Overheads 12