Crossbreeding and Breeding Methods in Livestock

General Agriculture for Competitive Exams for UPCATET PG / TGT, PGT / TA, STA etc.

About Lesson

Crossbreeding in livestock

Definition: Crossbreeding is the mating of animals from two different established breeds to combine desirable traits of both. Examples:

➤ Objectives:

➤ Ideal Exotic and Local Blood Ratio:

TYPES OF BREEDING

Inbreeding

Definition: Mating of closely related animals in the same breed within 4 generations (e.g., brother-sister, parent-offspring).
Advantage: Maintains pure line of a breed.

Outbreeding

Definition: Mating of unrelated animals of the same breed with no common ancestor for at least 4–6 generations.
Benefit: Avoids inbreeding depression and increases hybrid vigour.

Grading

Definition: A form of outcrossing where bulls of a recognized breed are mated with non-descript cows over successive generations. Example (Jersey Bull used on Non-descript Cow):

Trait	Description	Standard Values (For Comparison)
Age at 1st Calving	Age (days/months) when the cow/buffalo delivers its first calf.	– Indigenous: 36–42 months – Crossbred: 24–30 months – Exotic: 20–24 months
Lactation Length	Duration (days) the animal produces milk post-calving. “Standard lactation” = 305 days.	– Indigenous: 200–250 days – Exotic: 300–305 days – Buffalo: 280–320 days
Lactation Yield	Total milk (kg) produced in a lactation period (adjusted to 305 days).	– Indigenous: 1,000–2,000 kg – HF Crossbred: 3,000–4,500 kg – Murrah Buffalo: 1,800–2,500 kg
Dry Period	Non-lactating interval between drying off and next calving.	Optimal: 60–90 days (Longer periods reduce annual yield).
Inter-Calving Period	Days between two consecutive calvings. Impacts herd productivity.	Ideal: 12–14 months – Indigenous: 14–18 months – Exotic: 12–13 months
Peak Yield	Highest daily milk output (kg/day) during lactation.	– Indigenous: 6–8 kg/day – HF Crossbred: 15–20 kg/day
Average Fat %	Mean fat content in milk (critical for pricing).	– Indigenous cows: 4.5–5.5% – Buffalo: 6–8% – Exotic cows: 3.5–4.5%

Key Exam

305-Day Lactation: Standardized measure to compare yields across breeds.
Dry Period: >90 days reduces annual yield; <60 days risks metabolic disorders.
Inter-Calving Gap: Shorter gaps = higher lifetime productivity (asked in ICAR/UPSC).
Buffalo Traits: Longer lactation (280–320 days) and higher fat % than cows.
“Which trait directly impacts the number of calves born in a cow’s lifetime?” Inter-Calving Period

Comparison of local, exotic, and crossbreed cattle

Trait	Local/Indigenous Breeds (e.g., Sahiwal, Gir)	Exotic Breeds (e.g., Holstein-Friesian, Jersey)	Crossbred (e.g., HF × Sahiwal)
Birth Weight	18–22 kg	Jersey: 25–30 kg; HF: 30–40 kg	25–30 kg
Age at Maturity	30–36 months	12–15 months	18–24 months
Age at 1st Calving	36–42 months	20–24 months	24–30 months
Lactation Yield	1,000–1,800 kg	HF: 5,000–7,000 kg; Jersey: 3,000–5,000 kg	2,000–3,500 kg
Lactation Period	200–250 days	300–305 days	250–280 days
Dry Period	90–150 days	45–60 days	60–90 days
Inter-calving Period	14–18 months	12–13 months	13–15 months

Total Duration: 21 Days

🔸 1. Proestrus (2 Days)

🔸 2. Oestrus (1 Day)

Also called “heat period”
Female is receptive to the male
Ovulation occurs towards the end of oestrus
Graafian follicle ruptures, releasing ovum
Optimum time for insemination: If signs of heat appear in the morning, inseminate in the evening (12 hours after)

🔸 3. Metoestrus (4 Days)

🔸 4. Diestrus (14 Days)

Longest phase of the cycle
Uterus prepares for pregnancy
In case of no conception:
→ Involution (shrinking) of uterus takes place
→ Cycle starts again

🔹 SYMPTOMS OF HEAT IN CATTLE

Artificial insemination (ai)

Definition: The mechanical deposition of sperm in the female reproductive tract without natural mating.

Advantages of AI

Semen dilution & dose preparation

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