Fresh Cow Performance as Related to Management of Transition Cows and Metabolic Disease Overview Photo credit: K. Nordlund, UWSVM Transition cow management Metabolic diseases Fresh cow exams & treatment protocols Repro factors July 10, 2015 R. Tom Bass, II, DVM, PhD Renaissance Nutrition Fresh Cow Job Description: Calve without assistance and clean within 12 hours Experience no metabolic disease, no mastitis Have a strong appetite Milk 100 lb by 14 DIM (mature cows); 70 lb by 21 DIM (heifers) Lose no more than ¾ of a BCS Cycle by 30 DIM, show heat by 50 DIM, breed back by 110-120 DIM Top 10 Reasons Transition Cow Programs Get Ugly (adapted from Overton, 2001) 1. Lack of a standard monitoring and treatment program for fresh cows 2. Failure to achieve high DMI due to dry period feeding mgt. and/or poor quality forages 3. Overcrowding of close-up and fresh cows 4. Poor repro performance resulting in fat dry cows 5. Cleanliness of calving areas 6. Large numbers of grouping and/or diet changes during the transition period 7. Fresh cows in the low group 8. Poor heifer programs 9. Inadequate water availability 10. Substandard ration formulation 11. Heat stress When Dry Cows Get Heat Stressed Effects of Dry Cow Cooling on Milk Production May calve 2-3 weeks early 3-5 days early is typical Reduced calf birth weight (8-15%), vigor, and survivability Calves produce significantly less milk once they begin lactating (Montiero, et al, 2013) Compromised immune function Increased retained placentas Decreased colostral quality and/or quantity (?) Reduced dry matter intake (8-22%) DECREASED MILK PRODUCTION 1/15
Five factors that most significantly influence TCI 5. Fresh cow screening based on appetite & attitude 4. Larger freestalls- wider, open fronts (the 1980 s freestall is a miserable little container - KN) 3. Sand-based stalls, esp. post-calving (surface cushion) 2. Stable social groupings (no pen moves 3-10 days pre-calving) 1. Bunk space for all transition cows to eat simultaneously (30 per cow) The TCI was developed by Ken Nordlund, DVM, based on the assessment of 45-50 WI freestall herds averaging 600 cows. It evaluated more than 30 management practices. The COST of Fresh Cow Diseases Disease Avg. $$/Case (1998) Avg. $$/Case (2008) Culling Risk Mastitis $190 $259 32.7% RP/Metritis $254 $326 31.7% DA $374 $683 26.9% Ketosis $177 $228 32.5% Milk fever $208 $259 47.1% 1998 Values: Dead cow-$1400, Cull-$1000, Milk- $13.50/cwt, Day open- $2.50, Labor- $12/hr 2008 Values: Dead cow-$1800, Cull-$1100, Milk- $20.00/cwt, Day open- $3.00, Labor- $12/hr 2014 Values: Dead cow-$2000, Cull-$1600, Milk- $24.00/cwt, Day open- $3.50, Labor- $12/hr Fresh Cow Risks (2011 UW SVM study related to survival beyond 60 DIM) When Cows Leave the Herd (MN DHIA 10/96 10/01) Godden et al., 2003 The 4 L s: Lameness Low BCS Long dry period Labor-related problems Dystocia Stillbirth Retained placenta % Cows Leaving That Left in the 21 Day Period 12% 10% 8% 6% 4% 2% 0% 0-20 21-41 42-62 63-83 84-104 105-125 126-146 624,614 Cows Leaving 5,749Herds 147-167 168-188 189-209 210-230 231-251 252-272 273-293 294-314 315-335 336-356 357-377 378-398 399-419 420-440 21 DIM Interval Metabolic disease risk if a single risk factor root cause of metabolic disease is to be considered, that root cause would focus on the factors associated with dry matter intake in late gestation / early lactation cows. W. B. Epperson, DVM, 2005 Tri-State Nutrition Conference Proceedings 2/15
Prefresh stall stocking density reduced from 120% to 85%; Postfresh from 100% to 85% Source: Ken Nordlund Pen pressure and stocking rate Herding instinct Most cows in a pen prefer to eat at once Three/six row barns in transition groups are an issue 4 ft freestall width and three cows trying to eat Bedded pack barns can be issues as well, depending on feed bunk to pack ratio Green line is number of cows Red line is start-up milk Bedded pack Feed bunk vs. Bedded pack Feed bunk Case Study Date Case Study Cows in Fresh Pens % DAs Summit Milk Larger herd in Northeast Crowded Fresh Cow pens No changes in dry cow diet approach Opted to reduce cow numbers in fresh pens fall 2008 Aug Sept 08 157 7.7 89 Dec 08 Jan 09 130 4.4 April May 09 108 1.6 Mar Aug 09 109 4.3 107 3/15
Transition Cow Objective: The Interrelationship of Fresh Cow Diseases Minimize metabolic diseases Keep the dominoes in the box! Address identified fresh cow problems ASAP! Lameness ($355) Displaced Abomasum ($365) Disease Avg. $$/Case (1998) Avg. $$/Case (2008) Culling Risk Mastitis $190 $259 32.7% RP/Metritis $254 $326 31.7% DA $374 $683 26.9% Ketosis $177 $228 32.5% Milk fever $208 $259 47.1% 1998 Values: Dead cow-$1400, Cull-$1000, Milk- $13.50/cwt, Day open- $2.50, Labor- $12/hr Ketosis ($159) Metritis ($334) Hypocalcemia Milk Fever ($360) Mastitis ($216) Retained Placenta 2008 Values: Dead cow-$1800, Cull-$1100, Milk- $20.00/cwt, Day open- $3.00, Labor- $12/hr Fresh Cow Problems- What s Normal and What Should You Shoot For?? Condition Avg. Annual Incidence Target Rate Alarm Rate Retained Placenta 5-15% <8% >15% Metritis 7-25% <8% >16% Cystic Ovaries 10-13% <8% >18% DA 5-10% <4% >14% Ketosis (clinical) 3-9% <6% >15% K.I.S.S. Rule --- <5% >15% Subclinical Ketosis (SCK) 15%-45% (?) <20% >50% Subclinical Hypocalcemia 30% (?) <20% >40% Transition Cow Objective: Maintain proper calcium metabolism High potassium forages--risk Low DMI--risk Anionic salts (DCAD)--prevention Milk fever costs $250-375/case Predisposes to other problems Disease or Condition Increased Risk Associated with Milk Fever Association isn t necessarily cause & effect Dystocia 2.8X Retained placenta 2.3-6.5X Metritis 1.8X Ketosis 6-9X Mastitis 8.1X Displaced abomasum 3.4X Uterine prolapse 11.5X adapted from Curtis et al., 1983, and Markusfeld, 1987 4/15
Quantifying Periparturient Hypocalcemia Primiparous cows are at very low risk for low blood calcium around calving and probably should not be included in the monitoring program. Garrett Oetzel, DVM, UW-SVM, 2007 I suggest an alarm level for >30% for parturient hypocalcemia (defined as <8.0 mg/dl) in multiparous cows. - Oetzel Kronfeld et al., 1968 Quantifying Periparturient Hypocalcemia What percentage of first calf heifers are hypocalcemic at freshening?? 25%, based on 2002 NAHMS Dairy survey 54% and 53% of 2 nd, and 3 rd + lactation cows were hypocalcemic w/in the first 36 hours after calving (1700 cattle sampled) Recent Prince data shows that a higher %age of 1 st calf heifers are hypocalcemic at 48 hrs post-fresh than at calving Which animal are you evaluating?? Comparison of Clinical Chemistry Reference Intervals Currently Used in the U of Guelph AHL and Those Determined in Pre- and Post-calving Dairy Cows in Southern Ontario Analyte (mg/dl) AHL Precalving (n = 350-510) Postcalving (n = 530-550) Cholesterol 66-298 50-116 74-112 Glucose 45-77 48-86 41-94 Urea 18-48 13-48 11-47 Calcium 8.4-11.2 a 8.7-10.6 b 6.6-10.5 c Phosphorus 4.6-8.1 4.6-8.2 3.2-8.5 a,b,c different distribution curves (p 0.05) Quiroz et al., 2009 Quantifying Periparturient Hypocalcemia Low blood Ca + is normal & should be tolerable (to a degree) in recently fresh, high producing dairy cows MILK FEVER/clinical hypocalcemia is NOT (if in excess) It s not just how low it gets, but also how long it remains below normal How do we keep it at tolerable levels?? Hypocalcemia is associated with higher production (Jawor, et al., 2012) Versus similar case-control cows, cows with hypocalcemia: Produced 12.5 lb more milk/day in weeks 2-4 of lactation Ate 3.75 lb more dry matter/day in the two weeks prior to calving 5/15
Ration formulation strategies to minimize Ca + challenges Options Low Ca + Moderate Ca + High Ca + Anionic products Which do you choose?? Constants Keep cows eating High Mg + (0.40-0.45%) Low K + (<1.5% preferred, <1.2% better still); low Na + Moderate P - (0.33-0.38%) percentages expressed as % of ration dry matter Hypophosphatemia Causes/contributors: Colostrum synthesis/onset of milk production Late term fetal growth Hypocalcemia Increased PTH activity around parturition (increased salivary & renal P excretion- Horst, 1986) Decreased dietary intake? 35% of cows with LDAs were hypophosphatemic (Grunberg et al., 2005) Seen concurrently with hypokalemia (Peek et al., 2003) Artifact of recent IV dextrose administration? In dairy cows, plasma P concentrations routinely fall below the normal range at parturition Jesse Goff, DVM, PhD Hypophosphatemia (clinical, acute) Cheng et al., 1998 Source: J. Goff The creeper cow Down, but alert, somewhat mobile, and often attempts to get up No definitive physiologic explanation Difficult to replicate/induce experimentally (Rodehutscord et al., 1994) Seen in cows with adequate/excessive ration P content Possible association with compromised hepatic function (Staufenbiel and Gelfert, 2002; Grunberg et al., 2005) Must be treated with phosphate solutions, not phosphite Phosphite biologically unavailable Phosphate sources: Fleet Enema, others Oral Rx alternatives: 200 g monosodium phosphate or 300 g dicalcium phosphate (poorer 2 nd choice) Take-home Mineral Messages Ration Formulation: Keep Mg + high and K + low Maintain ration- and management-related factors that foster high dry matter intake Ca + content?? Don t fix what isn t broken If the current Ca + provision doesn t seem to work, change it (+/- 20 grams) & reevaluate Use anionic products if desired or needed, but supply at least 90 g Ca + - Or is the extra Ca+ needed? (Goff & Horst, 2012) Take-home Mineral Messages Blood mineral concentrations: Complete elimination of hypocalcemia in fresh cows is unrealistic try to reduce magnitude and duration Subclinical hypokalemia and -phosphatemia are relatively common, normal occurrences in fresh cows Hypomagnesemia and phosphatemia may occur secondary to hypocalcemia 6/15
Rules of the Road: Pre-fresh Management At least 2.5 ft. bunk space per cow Headlocks: 20% more than cows present At least 120 sq. ft. bedding area/cow 10% more freestalls than cows NO BBD!!! Low energy in the faroff dry cow ration Clean feed bunks At least 2 waterers in the pre-fresh pen Cows w/twins & heifers: 4-5 weeks in pre-fresh group Lameness problems already corrected BCS of 3.0 to 3.5 NO FAT COWS!!! Avoid Fat Cows The Importance of DMI to Immune Function The Importance of DMI to Immune Function Time for a 5 minute break??? Ketosis What are ketones? Results from negative energy balance Different types and degrees of severity Type II ketosis: a fresh cow disease that typically begins during the dry period Monitored through blood, milk, or urine ketone testing post-calving (or predicted by blood NEFAs pre-calving) Higher ketone concentrations expected in urine 7/15
Energy Balance in Transition Cows (Dr. Daryl Nydam, Cornell Univ.) Subclinical ketosis does bad things: Incidence of disease by pre-calving NEFA concentration (Dyk, 1995) 15-20% less likely to become pregnant Produce 1350 lb less ME305d milk (for lactation 2+ animals) Increases the risk of: DAs (9.7X) RP/metritis (17X) clinical ketosis (5X) May cost up to $330/case The Ketosis Cycle Anorexia (mechanism unknown) Ketosis Ketone body and CO2 production Fat Tissue Liver NEFAs esterified Triglyceride production Decreased LDL production Lipolysis Non-esterified fatty acids (NEFAs) in plasma Uptake by liver adapted from Nocek, 1995 Ketosis We must recognize that the production of ketones by the cow is a normal process during negative energy balance. We need to prevent clinical disease due to ketosis, but not this normal physiological process. - Mark Thomas, DVM Lowville, NY (Dairy Herd Management, January, 2008) Ketosis- diagnosis (Todd Duffield, DVM, recommendations) Urine ketones Ketostix is best test Must be read w/in 10 seconds Cost: 16-25 per strip Treat if moderate Milk ketones Keto-Test is best Measures BHBA Cost: about $2/strip Blood BHBA Highly accurate Cost: $2-$3/ test strip and $40 for meter Ketosis- diagnosis D. Nydam photo 8/15
Ketosis- Treatment/Prevention Is it energy balance or calcium? Propylene glycol (T/P) 10-12 oz. once daily for 5 days Calcium propionate (T/P) ¼-1 lb per day Rumen-protected choline (Reashure ) (P and T???) Rumensin (P) Rumen-protected niacin (Niashure )? (P) Glycerol? Chromium? (P) IV dextrose (T) Steroids (T) Vitamin B 12 injections (+/- butaphosphan), (T) Bypass methionine (P) Bypass fat KEEP COWS EATING!!! Probably both, at least at times in mature cows Symptoms of ketosis and hypocalcemia can be similar Low blood Ca+ is normal & should be acceptable; MILK FEVER (and clinical hypocalcemia) ARE NOT (if in excess) 2002 NAHMS Dairy Study: 25%, 54%, and 53% of 1 st, 2 nd, and 3 rd + lactation cows were hypocalcemic w/in the first 36 hours after calving (1700 cattle sampled) Chapinal, et al, JDS, 2012 (2365 cows sampled from 55 U.S. and Canadian freestall herds) In the week before calving, elevated serum NEFA or BHBA and/or low serum Ca + was associated with 3.5-7 lb/day milk loss across first 4 DHIA tests and increased culling risk Low Ca + weeks 1-3 post-calving associated with reduced 1 st service conception rates Controlled energy intake during the dry period (Illinois research from Drackley and colleagues) Overconsumption of energy during the dry period is common & makes cows behave metabolically like fat cows Lower DMI post-calving Slower production start-ups Increased negative energy balance & ketosis Far off dry period more critical than close-up Controlled energy intake during the dry period (Illinois research from Drackley and colleagues) Urine ketones? YES Ketosis Flow Chart NO Continue monitoring through 10-14 DIM Lower ration energy density by feeding straw and/or mature grass hay Helps maintain higher DMI, especially just before calving Target NE-L values (in CPM): 0.62-0.66 Mcal/lb for one-group dry cow 0.60-0.64 Mcal/lb for far-off diet in two group (ration) system 12-16% starch Trace or slight Good Re-evaluate tomorrow How strongly positive? Appetite, attitude & udder fill? Small or stronger Fair to poor Examine for other metabolic diseases 1) Drench with Ca+ propionate (1-1.5 lb) OR propylene glycol (300-400 ml) once a day 2) Give 250 ml IV dextrose on day 1 (reserve 500 ml dose only for cows w/large urine ketones!) 3) Vitamin B 12, 2000-3000 mcg 9/15
Retained Placenta (RP) or Retained Fetal Membranes (RFM) Photo courtesy of Dr. John Currin Non-nutritional reasons Dystocia, twins, early calving Disease of undernutrition (Chassagne and Chacornac) Decreased immune function Immune-related nutrients Cow factors Protein, energy intake Heat stress, ketosis Hypocalcemia (2.3-6.5X in risk) Manual removal can impair future repro performance Retained Placenta (RP) or Retained Fetal Membranes (RFM) FIVE CONDITIONS CLOSELY ASSOCIATED WITH RPs: (Wiltbank, 2008) 1) Inbreeding or genetic similarity between cow & calf 2) Calving induced with prostaglandin 3) Calving induced with corticosteroids (dexamethasone) 4) High stress prior to calving 5) Low Se or vitamin E status - More likely, and likely to be problematic, in older cows Causes of Metritis Overwhelming uterine challenge Retained placenta (50% go on to develop metritis) Dirty calving and/or fresh cow environment Human intrusion into the uterus Suboptimal immune function in the uterus Vitamins A and E; copper, zinc, selenium Protein, energy General immunosuppression by bugs Heat stress, ketosis Calcium challenges? Metritis How do you define metritis?? The post-partum uterus is rarely a sterile environment Uterine discharge is NORMAL for up to 3 weeks after calving A good working definition: The presence of abnormal uterine discharge (watery, stinky, and reddish) IN CONJUNCTION WITH sign(s) of systemic illness (fever, depression, poor appetite) Good or Bad?? Good or Bad?? Photos courtesy of Dr. John Currin Photos courtesy of Dr. John Currin 10/15
Cystic Ovarian Disease- Risk Factors fat dry cows genetics negative energy balance season (higher incidence in spring and fall changing day length influencing hormones?) Stress Mn deficiency? Vitamin E deficiency? Veterinary error poor uterine health/history of uterine health problems hormonal imbalances feeding estrogenic feeds (e.g.- clover contaminated by the mycotoxin zearalenone) excessive pro-oxidant intake? (high dietary concentrations of iron; excessively high concentrations of copper, selenium, zinc) Displaced Abomasum 90% occur between 1 and 30 DIM, with about 75% of those occurring by 15-20 DIM Can be either left- (LDA) or rightsided (RDA) Don t sit on it!!! Usually a secondary disease Multiple risk factors one common denominator (IMHO) DA Risk Factors from the literature Insufficient fiber Insufficient DMI Negative energy balance Excessive BCS High energy in prefresh ration Calving in winter or summer Hypocalcemia High genetic merit Genetics Low parity Giving birth to twins Early lactation Fresh Cow Fevers What denotes a fever? Temp. >103 F (heat stress may change this cutoff) What about below normal temperatures (<101 F)?? Possible causes/sources Uterus - GI tract Lungs/respiratory system - Other?? Is fever a normal post-calving occurrence?? "It is well documented that 14% to 66% of healthy cows exhibit at least one temperature of 39.5 (103.1) or greater within the first 10 DIM." Theriogenology 2014 July 1;82(1):121-31 Va Tech study results Fresh Cow Monitoring Different degrees and methods Should be done for at least 10-12 days At least every other day daily once a problem is identified Increases the odds of identifying small problems before they become big problems Remember & respect time budgets! Protocol adapted from Dr. John Currin 11/15
Drenching Cows Recommended by (some) veterinarians Popular on some dairies Opportunity to reduce metabolic disease and increase profitability Don t consciously use it as a long term Band-Aid If she s not chewing, you d better not be pumping! Summary of Drenching Recommendations Ensure competence of staff Focus on sick and high risk cows Select a drench that provides large dose(s) of Ca, other electrolytes, glucose precursors & rumen enhancers Use a large volume of water (8-10 gallons) Re-drench on subsequent days if necessary Transition Effects on Reproduction Metabolic diseases Energy balance/body condition loss Lameness Mastitis Events around calving have a profound impact on later fertility! Condition Odds Ratio CR Incidence,% Normal 1.00 50 40.0-60.0 Metritis,chronic.63 32 1.0-23.0 Acute metritis.68 34 6.5-8.3 Retained placenta.72 37 4.5-8.6 Ketosis.90 46 7.4 Lameness.83 43 0.3-3.7 Ovulatory dysfun..71 36 1.6-8.6 Data from: Ouweltjes et al. (1996), Lee et al. (1989), Grohn et al. (1990), Francos and Mayer (1988a; 1998b), Harmon et al. (1996). Adapted from Ferguson (2002). Negative Energy Balance Probably the biggest nutritional influence on reproductive performance Severity and duration both important Usually reaches its nadir at 12-20 days postcalving; typically lasts 70-90 days Cows losing >1 BCS were 1.5X less likely to conceive than cows losing <1 BCS (Domecq, MSU) First service conception rates lower for cows w/a BCS <=2.5 (Risco, et al., UFL) 12/15
Effects of Post-fresh DMI on Cow Performance (adapted from Staples et al., JDS, 1990) Dry Matter Intake Impact of Lameness on Reproduction and Productivity Variable Low Moderate High Dry matter intake, lb/day 33 39 41 Number of Cows 15 14 25 4% FCM yield, lb/day 63 70 74 Body weight change, lb/day -2.7-1.8-1.8 Days to 1 st ovulation >63 43 22 Days to 1 st heat 110 73 47 Days open 200 88 133 Sprecher, et al, 1997 Lame cows relative to herd average: 3X risk of increased days to first service 9X risk of increased services per pregnancy 8X more likely to be culled Hernandez, et al, 2001 Lame cows with claw lesions vs. healthy cows: Took 40 days longer to conceive Higher # of breedings per conception (5 vs. 3) Greater chance of being culled Impact of Lameness on Reproduction Lame cows vs. non-lame cows <30 DIM: Lower first service conception rate (17.5 vs 42.6%) Melendez et al., UFL-CVM, 2003 Higher incidence of ovarian cysts (25.0 vs 11.1%) Melendez et al., UFL-CVM, 2003 Lame cows <36 DIM are 3.5X more likely to experience delayed ovarian cyclicity Garbarino et al., UFL-CVM, 2004 Aureomycin Use in Dry Cows What WAS the label approval? 10 mg/lb BW for not more than 5 days for the treatment of bacterial pneumonia Small scale slaughterhouse study 45% of cull dairy cows (n=111) had some incidence of disease Taylor Packing: slaughters 1200 dairy cows/day 50/1200 with active lung lesions (4%) Aureomycin Use in Dry Cows Purported added benefit of HHW treatment/control Where s the data?? Oral CTC (22 mg/kg) for 3 weeks did NOT work (C. Guard) Where s the label approval??? CTC USE IN DRY COWS DEEMED ILLEGAL BY FDA-CVM IN EARLY 2010 Mastitis-Reproduction Link Growing body of evidence that mastitis can significantly impact reproductive success Cows with clinical mastitis (Barker et al., 1998): Increased days to 1 st service (94 vs 71) when occurring before 1 st service Increased SPC (2.9 vs 1.7) when occurring after 1 st service Increased days open (137 vs 92) when occurring after 1 st service No difference between Gram + vs Gram bugs 13/15
Mastitis-Reproduction Link Subclinical mastitis produces similar results (Schrick et al., 1999) Cows diagnosed w/mastitis during the first 45 days of pregnancy are 2.7X more likely to abort w/in the next 90 days (Risco et al., 1999) Greater risk of abortion after 70 days pregnant when SCC at breeding is greater than 400,000 (Jousan et al., 2005) Mastitis-Reproduction Link From a NY study involving 14,000+ cows and 55,000+ AI breedings (Hertl, et al., JDS, 2010) : Clinical mastitis from 14 days pre- to 35 days postbreeding reduced conception rate 80% reduction in conception rate when Gramnegative clinical mastitis occurred in the week after AI Clinical mastitis caused by Gram-negative bacteria was more detrimental to conception rate than clinical mastitis caused by Gram-positive bacteria Fresh Cow Job Description: Thanks for your attention! Calve without assistance and clean within 12 hours Experience no metabolic disease, no mastitis Have a strong appetite Milk 100 lb by 14 DIM (mature cows); 70 lb by 21 DIM (heifers) Lose no more than ¾ of a BCS Cycle by 30 DIM, show heat by 50 DIM, breed back by 110-120 DIM 14/15
Association isn t necessarily cause & effect Effect of chromium supplementation in lactating dairy cow diets on response in daily milk yield, lbs/h/d Cr suppl., mg/h/d 3.7 15.1 11.0 7.6 Hayirili et al., 2001 1.1 3.8 6.5 10 Pechova et al., 2002 1.5 6.25 Bryan et al., 2004 7.4 4 Al Saidy et al., 2004 5.5 7.5 Smith et al., 2005 0.4 3.7 10.4 22.56 10.2 22.56 Terramoccia 4.0 11.28 et al., 2005 3.2 11.28 5.7 10 10.1 10 McNamara & 5.5 10 Valdez, 2005 1.8 10 2.6 10.8 An Qiang et al., 2.8 7.2 2.1 2009 3.6 0.7 10.4 Sadri et al., 7.5 10.4 2009 11.9 6 8.8 Soltan, 2010 6 4.2 6 0.4 Nikkhah et al., 12.4 2011 3.5 6.2 7.9 8 7.3 8 Rockwell & Allen, 5.9 8 2011 3.1 8 6.7 8 Targhibi et al., 2012 6.1 8 Kafilzadeh et al., 2012 5.7 8 Ferguson, 2013 5.5 8 Rodriguez et al., 2014 1.1 8 Yasui et al., 2014 5.0 4.0 3.0 2.0 1.0 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0 13.0 Response in daily milk yield, lbs/h/d Denotes significance or trend for difference from control within study. Slide courtesy Dr. Ken Griswold, Kemin Transition/early lactation trial Heat stress trial Reproductive trial Question: How do you know spring is coming? Answer: You start seeing the deer again and the catfish are biting in Virginia 15/15