Table: Parameters Useful to Monitor Health and Production of Dairy Herds

Parameters Useful to Monitor Health and Production of Dairy Herds

Parameter	Goal
Adult Cow Disease
Average percent of herd lame	<25%
Metritis/endometritis incidence	<5%–25%
Subclinical ketosis (>1.2 mmol/L)	<10%
Clinical ketosis	<2%
Left displaced abomasum	<3%–5%
Milk fever	<3% of adult cows calving per month
Retained fetal membranes	<3% of cows calving per month
Cut point for ruminal acidosis	pH <5.5
Clinical mastitis monthly incidence	<3% of lactating herd
Culling and Death Loss
Annual average overall cull rate	35%
Annual average selective cull rate	>15%
Annual death loss	<10%
Annual disease and injury culling	<5%
Annual reproductive cull rate	5%–10%
% Removed <60 days in milk (lactation = 1)	<4%
% Removed <60 days in milk (lactation >1)	<6%
Udder Health and Milk Quality
SCC legal limit	750,000 cells/mL
SCC farm goal	<150,000 cells/mL (or adjust for a dairy)
Standard plate count legal limit	100,000 CFU/mL
Standard plate count farm goal	2,000–4,000 CFU/mL
Preliminary incubation count	2,000–6,000 CFU/mL
Bulk Tank Cultures - Bacterium
Streptococcus agalactiae	0 CFU/mL
Staphylococcus aureus	<50 CFU/mL
Staphylococcus spp	<1,000 CFU/mL
Mycoplasma spp	0 CFU/mL
Environmental streptococci	<1,000 CFU/mL
Coliforms	<500 CFU/mL
General Reproductive	Standard
Average days open	100–110 (ideally low 100's to achieve 12-mo calving)
Average gestation	283 days
Calving interval	13.5 mo
Average days in milk	200
Percentage of cows <90 days in milk	25%
Percentage of cows 90–180 days in milk	25%
Voluntary waiting period (VWP)	50–60 days for cows; 80–90 days for heifers
Days in milk at first breeding	Goal: VWP + 11 days
First service conception rate	40%
Heat detection	Goal overall >50% (national average <40%)
Intervals between breedings	18–24 days for 65% of cows
Length of estrous cycle	18–24 days
Overall conception rate	>35%
Services per conception	2
Definition of pregnancy rate	Heat detection rate × conception rate (21-day interval)
First cycle pregnancy rate	>30%
Percent pregnant by three cycles	>50%
Overall pregnancy rate	>20%
Percent of herd pregnant	50%
Pregnancy Diagnosis
When to do pregnancy checks	>40 days after being bred
Ability to locate amnion	42–65 days
“Membrane slip”	Day 30 to term
Ability to locate fetus	65–95 days
Placentomes present	After 3 mo of gestation
Ability to sex fetus	After 60–70 days of gestation
“Placentomes"	Day 70 to term
By amnion size (days)
35	7 mm (½ finger)
42	15 mm (1 finger)
48	35 mm (2 fingers)
53	55 mm (3 fingers)
58	75 mm (4 fingers)
62	90 mm (palm)
65	105 mm (hand)
By fetal crown-nose length (days)
70	1.5 cm (1 finger)
80	3.5 cm (2 fingers)
90	5.5 cm (3 fingers)
100	7.5 cm (4 fingers)
110	9 cm (palm)
120	10.5 cm (hand)
Postpartum Involution
Lochia (normal)
Day 1–2	Bright red blood, thick mucus, little smell
Day 3–7	Dark red, thin, odor not foul but objectionable
Day 7–14	Progressively less red to white to translucent, thicker, smell improves
Entire uterus palpable	2 wk
Full reduction in size	40–45 days
Epithelialization complete	40–45 days
Occurrence of endometritis	>26 days after calving
Full uterine involution	40–45 days postpartum
Abortion
Normal embryonic loss (<50 days)	<10%
Average rate of early embryonic loss	15%
Normal rate of abortion	3%
Major infectious abortion agents	Bovine viral diarrhea, mycotic, leptospirosis, Neospora
Noninfectious causes
Heat stress	>90°C, 80% relative humidity
Toxins	Nitrates: methemoglobinemia
Plants	Locoweed, snakeweed, pine needles, lupine
Urea	Excess rumen degradable protein or nonprotein nitrogen; milk urea nitrogen 10–14 mg/dL

Merck Manual

Parameters Useful to Monitor Health and Production of Dairy Herds