diff --git a/client/src/components/DogForm.jsx b/client/src/components/DogForm.jsx
index 0d741aa..750821a 100644
--- a/client/src/components/DogForm.jsx
+++ b/client/src/components/DogForm.jsx
@@ -12,9 +12,9 @@ function DogForm({ dog, onClose, onSave }) {
     color: '',
     microchip: '',
     notes: '',
-    sire_id: '',
-    dam_id: '',
-    litter_id: ''
+    sire_id: null,  // Changed from '' to null
+    dam_id: null,   // Changed from '' to null
+    litter_id: null  // Changed from '' to null
   })
   const [dogs, setDogs] = useState([])
   const [litters, setLitters] = useState([])
@@ -36,9 +36,9 @@ function DogForm({ dog, onClose, onSave }) {
         color: dog.color || '',
         microchip: dog.microchip || '',
         notes: dog.notes || '',
-        sire_id: dog.sire?.id || '',
-        dam_id: dog.dam?.id || '',
-        litter_id: dog.litter_id || ''
+        sire_id: dog.sire?.id || null,  // Ensure null, not ''
+        dam_id: dog.dam?.id || null,    // Ensure null, not ''
+        litter_id: dog.litter_id || null // Ensure null, not ''
       })
       setUseManualParents(!dog.litter_id)
     }
@@ -75,7 +75,14 @@ function DogForm({ dog, onClose, onSave }) {
 
   const handleChange = (e) => {
     const { name, value } = e.target
-    setFormData(prev => ({ ...prev, [name]: value }))
+    
+    // Convert empty strings to null for ID fields
+    let processedValue = value
+    if (name === 'sire_id' || name === 'dam_id' || name === 'litter_id') {
+      processedValue = value === '' ? null : parseInt(value)
+    }
+    
+    setFormData(prev => ({ ...prev, [name]: processedValue }))
     
     // If litter is selected, auto-populate parents
     if (name === 'litter_id' && value) {
@@ -97,11 +104,17 @@ function DogForm({ dog, onClose, onSave }) {
     setLoading(true)
 
     try {
-      const submitData = { ...formData }
-      
-      // Clear litter_id if using manual parent selection
-      if (useManualParents) {
-        submitData.litter_id = null
+      const submitData = { 
+        ...formData,
+        // Ensure null values are sent, not empty strings
+        sire_id: formData.sire_id || null,
+        dam_id: formData.dam_id || null,
+        litter_id: useManualParents ? null : (formData.litter_id || null),
+        registration_number: formData.registration_number || null,
+        birth_date: formData.birth_date || null,
+        color: formData.color || null,
+        microchip: formData.microchip || null,
+        notes: formData.notes || null
       }
       
       if (dog) {
@@ -254,7 +267,7 @@ function DogForm({ dog, onClose, onSave }) {
                 <select
                   name="litter_id"
                   className="input"
-                  value={formData.litter_id}
+                  value={formData.litter_id || ''}
                   onChange={handleChange}
                 >
                   <option value="">No Litter</option>
@@ -277,7 +290,7 @@ function DogForm({ dog, onClose, onSave }) {
                   <select
                     name="sire_id"
                     className="input"
-                    value={formData.sire_id}
+                    value={formData.sire_id || ''}
                     onChange={handleChange}
                   >
                     <option value="">Unknown</option>
@@ -292,7 +305,7 @@ function DogForm({ dog, onClose, onSave }) {
                   <select
                     name="dam_id"
                     className="input"
-                    value={formData.dam_id}
+                    value={formData.dam_id || ''}
                     onChange={handleChange}
                   >
                     <option value="">Unknown</option>