ANSC 464 LECTURE 7

ANSC 464: Lifecycle Nutrition of Cats - Gestation and Lactation

Cat Developmental Stages

Cats undergo distinct developmental stages, each with varying nutritional needs:

• Ten days old: Early neonatal stage.
• Three weeks old: Continued rapid growth.
• Five weeks old: Increasingly active, starting to explore food.
• Eight weeks old: Learning social interactions with littermates and other pets.
• Fourteen weeks old: Further growth and exploration.
• Five months old: Sexual maturity may be reached, though this varies.
• Adult cat: Full size and maturity typically achieved around one year of age.

Nutrient Requirements Overview by Life Stage

Objectives of Lifecycle Nutrition

• Understand lifecycle nutrition specific to cats.
• Focus on reproduction:
  • Gestation and lactation phases.
  • Detailed discussion of nutrient requirements during these critical periods.

Main Objectives of a Good Feeding Program for Reproductive Cats:

To ensure optimal health of the queen and successful development and survival of her offspring, addressing the unique physiological demands of pregnancy and milk production.

Obesity During Gestation

Obesity in queens during gestation can have significant negative impacts on pregnancy outcome:

• Stillbirths: Increased risk of fetuses being born dead.
• Dystocia: Obstructed or difficult labor requiring intervention.
• Cesareans: Higher likelihood of needing surgical delivery rather than natural birth.

Correction: A queen's weight and Body Condition Score (BCS) must be corrected before pregnancy to mitigate these risks.

Body Condition Score (BCS)

Regular monitoring of a cat's BCS is crucial for managing weight throughout its life, especially during reproduction. BCS ranges from very thin to obese:

• Very Thin: Ribs visible, very small waist, muscle may appear sunken.
• Thin: Ribs visible, muscle thin, small waist.
• Ideal: Ribs not visible but easily felt, waist proportional, muscles full.
  • Recommendation: Watch regularly, do not let condition increase, and remember it can decrease.
• Overweight: No waist, ribs hard to feel, fat visible over the tail base and under the rib cage.
  • Actions: $\downarrow$ reduce energy content, $\uparrow$ increase fiber quantity.
• Obese: Waist larger than ribs, ribs cannot be felt, fat visible throughout.
  • Actions: $\downarrow$ reduce energy content, $\uparrow$ increase fiber quantity.

Gestation & Lactation - Energy Requirement Trends

(Based on graphical representation of Food Intake and Body Weight as Percent of Normal)

• Early Gestation (~weeks 1-4): Food intake and body weight remain relatively stable or slightly increase.
• Mid-to-Late Gestation (~weeks 5-9):
  • Food intake shows a significant increase, peaking around weeks 6-7.
  • Body weight increases steadily, especially in the last 4 weeks.
• Parturition (P): A sharp drop in body weight occurs at birth.
• Lactation (~weeks 1-6):
  • Food intake typically reaches its highest point, significantly above normal, to support milk production.
  • Body weight gradually decreases throughout lactation as the queen expends energy producing milk.
• Energy Balance: During lactation, the high energy demand for milk production often leads to a negative energy balance if food intake does not meet requirements, resulting in weight loss for the queen.

Gestation - Differences Between Bitches and Queens

Energy Requirement - Gestation

• Weight Increase: The queen's weight increases linearly during gestation, which directly impacts her energy requirement.
• Food Intake Fluctuations:
  • Decline in food intake: Observed two weeks after mating (associated with fetal implantation) and again in the last week of gestation.
  • Peak of food intake: Occurs between $6$ to $7$ weeks of gestation.
• Metabolizable Energy Requirement (MER) for Pregnant Queens (NRC, 2006):
  • $\text{ME (kcal)} = 140 \times \text{BW}^{0.67}$

Water Requirement - Gestation

• There is an increased need for water during pregnancy.
• This is due to the expansion of extracellular fluid compartments and the development of maternal and fetal tissues.

Protein Requirement - Gestation

• Protein synthesis is greatly increased during gestation to support the rapid growth and development of fetuses.
• Protein quality and quantity are critical to provide essential amino acids for this development.
• Recommended Allowance (NRC, 2006) per $1,000$ kcal ME:
  • Total Protein: $53$ g
  • Arginine: $3.75$ g
  • Methionine + Cysteine: $2.25$ g

Effects of Protein Deficiency - Gestation

Severe protein deficiency during gestation can lead to a range of adverse outcomes:

• $\downarrow$ Birth weight: Kittens born smaller than normal.
• $\uparrow$ Neonatal mortality: Increased death rate in newborn kittens.
• $\downarrow$ Immunocompetence: Compromised immune system in offspring.
• Delayed home orientation in kittens.
• Aberrant locomotor development in kittens.
• Emotional responsiveness issues.

Taurine Requirement - Gestation

• Essential for normal reproduction and fetal development.
• Taurine deficiency in gestation can cause:
  • Delayed growth and development in fetuses.
  • Fetal death near the $25\text{th}$ day of gestation.
  • Abortions.
  • Fetal deformities.
• Recommended Allowance (NRC, 2006) per $1,000$ kcal ME:
  • Taurine: $0.13$ g

Fat Requirement - Gestation

• High energy demand during gestation makes fat a crucial nutrient.
• Adequate fat intake can improve reproductive performance by influencing:
  • Number of kittens per litter.
  • Mortality rate of offspring.
  • Overall reproductive efficiency.
• DHA (Docosahexaenoic acid) is important for neural development in fetuses.
• Severe arachidonic acid deficiency can have significant negative impacts (though specifics not detailed in slide).

Fat Recommended Allowance (NRC, 2006) per $1,000$ kcal ME:

• Total Fat: $22.5$ g
• Linoleic Acid: $1.4$ g
• $\alpha$-Linolenic Acid: $0.05$ g
• Arachidonic Acid: $0.05$ g
• EPA + DHA: $0.025$ g

Calcium (Ca) and Phosphorus (P) Requirement - Gestation

• Increased demands for Ca and P are crucial for fetal skeletal development.
• No experimental data specifically for gestating queens is highlighted.
• Eclampsia (seizures due to low blood calcium) in cats is uncommon and tends to occur in the last three weeks of gestation rather than early lactation.
• Recommended Allowance (NRC, 2006) per $1,000$ kcal ME:
  • Ca: $2.7$ g
  • P: $1.9$ g
  • Ca : P Ratio: $1.1$ to $1.5 : 1$

Other Minerals - Gestation

• Magnesium (Mg): No restriction of Mg in reproducing queens. Recommended allowance: $125$ mg/$1,000$ kcal ME.
• Copper (Cu): A cofactor in many metabolic pathways.
  • Deficiency can lead to: Fetal death, abortions, craniofacial deformities, cerebral dysgenesis, histochemical defects of the aorta, among others.
  • Highly available Cu sources: Sulfates and chelates.
• Vitamins: While not explicitly detailed, essential vitamins (e.g., A, D, E, B-complex) would also be critical for gestation.

Key Nutritional Factors for Gestating Queens (NRC, 2006)

Lactation

• Lactation is the most energy and nutrient demanding life stage for a queen.
• The queen needs sufficient energy stores at the onset of lactation.
• Nutrient requirements during lactation are directly proportional to the number of kittens in the litter.
• Lactation typically lasts for $7$ to $9$ weeks, depending on the breed, kitten growth rates, and management practices.
• Link to BCS: A queen's Body Condition Score greatly affects her ability to sustain lactation. Queens starting lactation too thin may struggle to produce enough milk, while those too heavy may have other health complications or difficulty mobilizing fat reserves efficiently.

Energy Requirement - Lactation

• Energy requirements during lactation combine maintenance needs with the demands of milk production.
• Energy needed for milk production changes weekly in terms of both energy content and yield.
• Litter size significantly impacts milk yield and, consequently, the queen's energy demands.
• Estimated Milk Production (as a percentage of the queen's body weight):
  • Early lactation: < $2\%$ body weight
  • Mid-lactation: $5$ to $6\%$ body weight
  • Peak lactation: $8\%$ body weight of queen

Lactation Energy Requirement (Peak Demand)

• Peak milk production and thus peak energy demand occur around $3$ to $4$ weeks of lactation.
• This period often presents a discrepancy with food intake, as queens may not be able to consume enough food to meet the extremely high energy demands.

Energy Requirement Formulas for Lactating Queens (NRC, 2006)

These formulas calculate Metabolizable Energy (ME) in kcal, based on the number of kittens ($ext{BW}$ = Body Weight in kg, $ext{L}$ = factor for stage of lactation):

Lactation Stage Factor (L) from Week 1 to Week 7:
$L = [0.9, 0.9, 1.2, 1.2, 1.1, 1.0, 0.8]$

Example Calculation: For a queen weighing $3.5$ kg at mating, with $4$ kittens, at peak lactation (Week $3$, so $L=1.2$):
$\text{ME kcal} = 100 \times 3.5^{0.67} + (60 \times 3.5 \times 1.2)$
$\text{ME kcal} = 100 \times 2.31 + 252$
$\text{ME kcal} = 231 + 252 = 483 \text{ kcal}$
This calculation demonstrates that energy requirements can be roughly double the maintenance needs during peak lactation.

Protein Requirement - Lactation

• Increased demand for milk protein synthesis is paramount.
• A $4$-kg nursing queen with a large litter can have a milk protein output of approximately $19$ g crude protein per day.
• Recommended Allowance (NRC, 2006) per $1,000$ kcal ME:
  • Total Protein: $75$ g
  • Arginine: $3.8$ g
  • Methionine + Cysteine: $2.6$ g
  • Taurine: $0.13$ g
• Protein source: Should be highly digestible and have high biological value, with animal tissue being preferable.
• Consequence of low protein intake: Reduced milk production, compromised kitten growth and development, and potential negative impacts on the queen's health and body condition.

Fat Requirement - Lactation

• High energy demands during lactation are best met by feeding energy-dense foods.
• Moderate to high fat foods are known to enhance lactation performance.
• Increased energy density of food due to higher fat content can lead to:
  • $\uparrow$ Kitten survival.
  • $\uparrow$ Growth rate of kittens.

Fat Recommended Allowance (NRC, 2006) per $1,000$ kcal ME:

• Total Fat: $22.5$ g
• Linoleic Acid: $1.4$ g
• $\alpha$-Linolenic Acid: $0.05$ g
• Arachidonic Acid: $0.05$ g
• EPA + DHA: $0.025$ g

Long-Chain PUFAs in Milk:

• Arachidonic acid: $\,0.59\%$ of total milk fat.
• Docosahexaenoic acid (DHA): $\,0.21\%$ of total milk fat.

Calcium (Ca) and Phosphorus (P) Requirement - Lactation

• There is an increased demand for Ca and P due to significant milk production.
• Recommended Allowance (NRC, 2006):
  • Ca: $358$ mg/kg BW OR $2.7$ g/$1,000$ kcal ME
  • P: $263$ mg/kg BW OR $1.9$ g/$1,000$ kcal ME
  • Ca : P Ratio: $1.1$ to $1.5 : 1$

Carbohydrate Requirement - Lactation

• There is no true soluble carbohydrate (sugar) requirement for cats.
• However, digestible carbohydrates can serve multiple purposes:
  • May spare protein from being used as an energy source.
  • Help maintain blood glucose levels.
  • Provide substrate for lactose production in milk.
• Recommendation: A diet containing $\ge 10\%$ DM (dry matter) soluble carbohydrates (sugar) is suggested.
• Note: Solid data on specific carbohydrate requirements for lactating queens is lacking.

Key Nutritional Factors for Lactating Queens (NRC, 2006)

Summary of Nutrient Requirements

Note: While not explicitly shown in the lactation summary, fiber intake during lactation is generally maintained rather than decreased, to support gut health and satiety.