This study aims to determine how sustainably and effectively a meat ewe flock may be bred and milked on the STAR Accelerated Lambing System schedule adapted to a total dairy situation. The Cornell University Dorset, and Dorset X Finnsheep flock is managed in three STAR groups (STAR-R, STAR-B, STAR-G) that each are either lactating, in early gestation and dry or in late gestation and dry. The STAR groups undergo consecutive lactations, with each group lambing and lactating 3 times in this 2-year research project. Applying the STAR Accelerated Lambing System to dairy production with lambs taken away after 12 h and ewes being milked for the first time on DIM 1 leads to short and frequent lactations. The ewes in each STAR management group will lactate for 73 to103 days, with breeding on day 73 of lactation, leading to ~219-day lambing intervals.
The experiment is designed as a triply replicated 3×3 Latin Square (Table 1). Each square contains sheep (n > 12) randomly assigned to 3 pens (A, B, C) in 3 STAR groups (STAR-R, STAR-B, STAR-G), 3 lactations (1, 2, 3), and 3 diets (30, 35, 40) orthogonally allotted in each lactation and STAR group. Variation due to pen, lactation, and group may effectively be removed by this design to maximize the probability of detecting differences.
We propose that milking sheep able to breed out of season on the STAR Accelerated Lambing System system can achieve equal or higher milk yields year-round in 365 days than possible with one annual 180-day dairy sheep lactation, utilizing the higher peak milk yields of many meat breed ewes in comparison to dairy breed ewes. Higher litter sizes of traditional meat ewes as well as the ability to lamb up to 1.67 times per year on the STAR management system will lead to a higher lamb crop, to more product sold and subsequently to higher profits. To be able to uphold high productivity, fecundity, and fertility while maintaining optimal health and body condition, elevated levels of nutrients need to be made available by the diet fed.
Goals of this research encompass: 1) A blueprint for milking sheep in short and frequent lactations on the STAR accelerated management system; 2) The pursuit of a dual-purpose (meat and dairy) breed and system; 3) The identification of ideal levels of fermentable fiber in diets for high producing dairy ewes. With these published achievements, farmers may increase their income by being able to produce and market product year-round, sell more and diversified product (dairy and meat), and feed their animals to maximize health and production.
- Determine optimal dietary levels of fermentable fiber (NDF) for maximum milk production, optimal ewe body condition, fertility, and health. Verify previous observations about the positive effect of fermentable NDF on feed intake and milk production.
- Record observations on milking behavior of meat breed ewes
- Record health problems and responses to treatments.
- Record prolificacy and lamb survival under the STAR accelerated system in a milking sheep environment.
- Compare published values for 190-day, yearly lactations of traditionally-milked dairy-breed ewes with yield and components of Finnsheep x Dorset ewes milked in 73- to 103-day lactations.
- Evaluate the sustainability of a flock of frequently milked traditional meat sheep.
- Update feed requirements and economic outputs of the SheepFlock financial simulation with data from the milking project and provide an easily accessible interface to serve as a management tool for sheep farmers.
The dairy operates year-round. The lambs are taken away from their dams 12 h after birth and reared artificially on free-choice cold milk. The milk collected in the parlor is cooled down and fed back to the lambs. The dam enters production on DIM 1.The milking ewes are milked and fed twice a day. Milk yield is recorded for each individual ewe at each milking, 7AM and 5PM. Amounts fed and refusals are recorded for each dietary pen twice a day at milking. Milking ewes and lambs are weighed weekly. Feed and refusal samples are collected weekly and digestibility is determined in the lab using acid insoluble ash and aNDFom method. Weekly milk samples are collected for analysis of milk components by the lab of Dr. Dave Barbano, Cornell University, Department of Food Science. Fecal samples are collected every 3 weeks for determination of digestibility using acid insoluble ash as a marker. A device to sample rumen fluid was developed and is used every three weeks to acquire samples from individual ewes (3 samples per ewe and lactation period). The fluid is measured for pH and will be analyzed for volatile fatty acid composition to complement the nutritional trial of this study.
The following results are preliminary, incomplete, and do not represent the final results of this ongoing research project.
1.Determine optimal dietary levels of fermentable fiber (NDF) for maximum milk production, optimal ewe body condition, fertility, and health. Verify previous observations about the positive effect of fermentable NDF on feed intake and milk production.
The participating ewes of each STAR group were randomly assigned to pen groups (A, B, C), where they receive one of the experimental diets (Table 2) differing in their concentration of potentially fermentable Neutral Detergent Fiber (pfNDF).
Higher concentration of pfNDF in the diet was observed to be correlated with higher intakes in two previous experiments (Schotthofer et al., 2007; Hein et al., 2010) done at Cornell University with ewes nursing triplets, and growing lambs, respectively. These results contrast with data from lactation 1 in the current experiment. The DM intakes shown in Figure 1 include ad libitum offered pelleted diet and a small amount of hay (~300g ewe/day). All three STAR groups (STAR-R, STAR-B, STAR-G) in lactation period 1 showed the lowest intakes in Pen C which was fed diet pfNDF40 with the highest (40%) amount of potentially fermentable NDF (Figure 1). Not all STAR groups have finished lactation period 2 yet, STARG will be dried off January 11. Hence feed intake data has not yet been analyzed for lactation period 2.
In lactation period 1 the lower amounts of intake had a negative impact on milk production. For all STAR groups in lactation period 1, Pen C (40% pfNDF diet) produced the lowest milk yields (Figure 2).
As can be observed below (Figure 3) weight gains behave inversely to milk production. Nutrients that are not partitioned towards milk production may be accumulated in the adipose tissue. The slight loss in weight for diet groups 30% and 35% pfNDF reflects the higher milk production of these groups in the first part of lactation; the vertex for both groups occurs when milk productions starts to decline ~40 DIM.
2. Record observations on milking behavior of meat breed ewes.
Milking behavior has been recorded in the beginning of lactation and at the end of lactation. Both values are reported. Milking behavior is scored from 1: No kicking, no skittishness, ease of entering and leaving the platforms, milking machine stays on, to 2: Slightly skittish, needs parlor bait to easily enter platform, nervous, kicks off machine occasionally, to 3: Very skittish, kicking, machine needs to be held in place, no ease of entering the platform and head gate, very nervous. By reporting both, initial behavior and behavior at the end of lactation, improvements can be assessed. For lactation period 1 (n=40) milking behavior scores are slightly higher with 1.95-1.43, than for lactation period 2 (n=47) with 1.62-1.28. Both scores indicate improvement throughout the lactation as well as improvement from the ewe’s first towards the second lactation.
3. Record health problems and responses to treatments.
Health issues and animal’s response to treatment are recorded. Overall the flock is very healthy, and the following circumvents the extent of serious incidents since October 2016: (Table 3)
4. Record prolificacy and lamb survival under the STAR accelerated system in a milking sheep environment.
Overall conception rates between 75% and 100% can be reported throughout the year (Table 4). Different methods were used to synchronize breeding, ranging from natural breeding (no aid used) to teaser rams (vasectomized rams 10 days prior to start of breeding), to hormonal synchronization (CIDRs, sponges), or a combination of the above. 69% to 93% of the pregnant ewes conceived in and lambed ~146 days after the first reproductive cycle (17 days in sheep).
Reproduction data for lactation period 1 as well as lactation period 2 for STAR groups STARR and STARB is summarized below (Table 5). With a total of 145 live lambs delivered, there were 3.15 live lambs per ewe between October 2016 and October 2017. Of these lambs, 4 died, 17 were kept for replacements, and 124 were sold as breeding stock or at the Dryden livestock sale. Average daily gain of these lambs was 0.61 lb/d at an average age of 64 days.
5. Compare published values for 190-day, yearly lactations of traditionally-milked dairy-breed ewes with yield and components of Finnsheep x Dorset ewes milked in 73- to 103-day lactations.
6. Evaluate the sustainability of a flock of frequently milked traditional meat sheep.
7. Update feed requirements and economic outputs of the SheepFlock financial simulation with data from the milking project and provide an easily accessible interface to serve as a management tool for sheep farmers.
Objectives 5, 6, and 7 will be accomplished when the experiment is completed. The data of the entire experiment is needed to report accurately on these objectives.
Hein, D. C., M. L. Thonney, D. A. Ross, and D. E. Hogue. 2010. Effect of level of intake on digestibility of NDF of soybean hull diets in sheep. Journal of Dairy Science 93:785-785.
Schotthofer, M. A., M. L. Thonney, and D. E. Hogue. 2007. Effect of level of fermentable NDF on feed intake and production of lactating ewes. Journal of Animal Science 85:180-181.
Upon conclusion of this study the data collected will be used to predict milk yield, lamb crop and profit in the SheepFlock management tool for dairy and meat sheep production. Better predictions will allow for more accurate planning at the farm level in areas like investment, marketing and nutrition. The software will be published open source on the Cornell Sheep Program website, as well as on the soon to be published Small Ruminant Dairy website.
Education & Outreach Activities and Participation Summary
The Cornell Sheep Dairy has been successfully running for the past 14 months. It is mainly student operated and is managed by the graduate student researcher and the PI of this project, Dr. Mike Thonney. So far 20 undergraduate students and interns have been taught how to milk, feed, handle ewes, and how to process, feed, and handle lambs. We are continuously training new students to ensure staff to operate the dairy.
This research idea was presented at the 22nd Annual Dairy Sheep Association of North America Symposium held at Cornell University, 2 to 4 December 2016, and entailed a proceedings publication “Fermentable Fiber for Milking Sheep on the STAR System”, Proceedings of the 22nd Annual Dairy Sheep Association of North America Symposium. Preliminary results were presented at the Cornell Nutrition Conference (17 to 19 October 2017) with a conference publication “Management and Nutrition for Milking Sheep in Short and Frequent Lactations”, Cornell Nutrition Conference 2017 Proceedings, Syracuse, NY.
Multiple lab sessions and lectures were taught by the graduate student researcher on this project for Cornell University undergraduate animal science classes ANSC 3800 Sheep, ANSC 2050 Sustainable Animal Agriculture, and ANSC/IARD 4000 Feeding the World. Activities included milking sheep, processing lambs, calculating (ideal) nutrient intake, and assessing system productivity and profitability.
In the past 8 months 450 followers were accumulated on the Cornell Sheep Dairy Instagram @cornellsheepdairy that are mainly small-scale dairy and meat sheep farmers around the country.