Young Bull Semen Theory v Practice
	At £3-8 per straw it’s potentially a great deal - but should we use them?
	Across the board unproven young bull semen is not for every one, but the industry benefits by testing more
	young bulls - particularly those less related to the breed. The herd owner benefits by rapid genetic progress
	at substantial cost savings
	Take Home Messages
	1  Young unproven bulls of high genetic merit have a real place in the UK & not just for the short term
	2  Used intelligently by the commercial producer they can boost financial performance - consistently
	3  By the time a well proven sire hits the lists, there is or will soon be semen of his sons available - use it
	4  Beware of Slippage - sons of sires on average show lower PIN2000 ratings than the sire 10-30% less
	so use only sons showing high Animal Model PTA's,  do pay attention to commercial type
	5  Maximise the law of averages by selecting only 10 straws per young bull and 30 straws / 100 cows
	of a same mating
	6  Use mating software that minimises inbreeding where possible to 3% (Grandson x Granddaughter)
	If the herd is already inbred by cousin, aunt nephew relationships be very selective of matings
	Seek young bulls less related to the breed -Vik KAI at 2% full relationship was one such - and in
	retrospect superior to Blackstar (16% related) for Productive Life but with similar production.
	7  Calving ease cannot be predicted with accuracy on maiden heifers,  sons of sires with
	a good history of easy to average calving should be chosen.  Reduce straws to 5 per young bull
	Slippage
	Taking the UK proof of Celsius and Mascot,  both of whom are sires of many sons, we would expect
	their sons to show on average similar PTA's for type and production.  In practice this is not the case
	For 244 sons of Mascot PIN 2000 is 82% that of the father - for 29 Celsius sons its 72% of the father
	WHY?  Matings may be to bull mothers that demonstrate more type than production, ie non Random
		Action:	On average Young bulls will deliver less than the fathers PTA.
			Select young bulls which have the highest Animal Model PTA
	Mendelian Inheritance
	The "gene lottery" at conception determines whether a stud's a dud or a winner.
	The Animal Model gives a prediction from all recorded relatives of the likely Average PTA's of a mating -
	We don’t know what happens to the share out of genes at conception from an individual mating, only
	a wide spread proof will do this.  Lets look at 10 proven sons from Celsius x Mascot matings.  Their
	average PIN 2000 of 56 exceeds a simple parent average of 52 but Festival at 86 won whilst Elmo "also ran"
	The Model is more reliaBULL than a simple parent average but is never as accurate as a wide spread
	daughter proof ie 100 daughters in 100 herds.  A wide spread proof is not 150 daughters in 40 herds with
	70% daughters in 1st herd.  In such cases the proof has the potential to be well and truly fixed, thus for
	UK proven sires such as Rosepary Thor, there will be a question mark whilst the first herd dominates
		Action:	Young bulls are by no means proven in practice, cast a wide net.
			To Maximise the law of Averages, Maximise 10 straws per young bull
			and 30 straws per 100 cows of a same mating ie Celsius x Blackstar
	Table: Celsius x Blackstar Matings
		Celsius  UK Proof	Celsius Sons  (29)	Mascot Sons  (244)	Mascot UK Proof	Simple Parent Average (Celsius + Mascot)/2	Actual  Proof Celsius (S) X Mascot (DS) 10 Sons	Highest Celsius x Mascot =Festival	Lowest Celsius x Mascot =Elmo
	PIN	65	47	43	52	52	56	86	38
	PLI	59	44	44	49	49	57	83	38
	SCC	16			9
	SCC Rlb	98			99
	Type Merit	1.8	0.4	0.6	0.8	0.9	0.5	0.2	0.9
	Dairy	2.2	0.6	0.9	1.1	1.2	0.4	0.7	0.5
	Body	-0.5	-0.5	0.4	0.4	-0.1	-0.5	-0.1	-0.8
	Legs & Feet	3.8	1.2	0.0	-2.1	0.7	0.8	1.2	1.1
	Mammary	1.7	0.3	0.6	1.2	0.9	0.7	-0.1	1.4
	Dtrs	1773			1962			44	42
	ST	-0.8	-0.6	-0.0	-0.1	-0.4	-0.5	-0.3	-0.7
	CW	-2.9	-2.0	0.2	1.4	-0.8	-1.4	-0.8	-1.6
	BD	-1.2	-0.6	0.6	0.9	-0.1	-0.6	-0.1	-1.2
	ANG	2.0	0.5	0.9	0.6	1.0	0.3	0.7	0.4
	RA	-0.2	-0.0	-0.2	-1.0	-0.3	-0.1	0.4	-0.4
	RW	-2.6	-1.2	0.2	0.8	-0.7	-0.9	-0.3	-1.3
	RLS	-2.2	-0.8	0.3	1.9	-0.2	-0.5	-0.7	-0.7
	FA	1.8	1.1	-0.4	-1.5	0.2	1.4	0.6	1.6
	FUA	0.4	-0.4	0.0	0.6	0.2	-0.0	-0.5	0.0
	RUH	1.4	0.8	0.8	1.5	1.1	1.2	1.0	1.4
	US	0.8	0.2	0.2	0.1	0.3	0.2	-0.9	1.4
	UD	-0.7	-0.6	-0.6	-1.0	-0.7	-0.4	-2.1	0.3
	TPL	1.0	-0.1	0.6	1.5	0.8	0.5	-0.6	1.5
	TL	2.3	1.2	-0.6	-0.7	0.5	0.2	0.4	0.9