Gilt service to farrowing

Lifetime productivity is related to overall ‘fitness’. Body mass is important and gilts should be fed a diet that facilitates both fat and lean-meat deposition.

In situations where gilts have a high growth rate, or culling for leg problems has been an issue, feed intake should be restricted to 80–90% of appetite.

Factors that should be considered when deciding when to serve gilts include:

• System, e.g. indoors, outdoors, semi-extensive
• Housing, e.g. separate gilt groups or integrated with the sows
• Previous experience of gilts’ productivity
• Actual and expected sow longevity

Typical service targets

• 135–170 kg liveweight
• 220–270 days of age
• Body condition score (BCS) 3–3.5

By service, gilts will have experienced at least one heat cycle and reached the required stature and body condition.

Preparing for service

If you are using a progestogen to control oestrus, you can ensure over 90% of gilts are cycling five to seven days post-withdrawal with the following steps:

• Ensure that the gilt has already reached puberty
• Don’t start the programme if the gilt is already in oestrus
• Preferably, feed the gilts individually or use a new oral doser; gilts can be trained with apple juice or cod liver oil
• If group feeding, initially feed 1 kg of feed plus the progestogen per gilt, distribute, allowing sufficient space for the gilt to eat her allocation. Feed the remaining daily allowance once the treated food has been consumed
• Once the progestogen has been withdrawn, the gilts should be placed on ad-lib feeding and receive daily boar contact to stimulate oestrus as normal

Feeding strategy

When gilts are not on an oestrus synchronisation programme, they are generally fed ‘to appetite’ or on an ad-lib basis up to service. An exception to this is where growth has been restricted due to the gilts’ inherent fast daily growth and/or problems with lameness culling. These should be fed ad lib for the cycle, or at least the last 14 days of the cycle prior to service, to flush the gilts and optimise their ovulation rate.

Familiarisation and stockmanship

It is important that gilts are familiar with moving to the heat-detection/AI facilities and that they are also allowed to explore the area, including meeting the boars. Familiarisation will reduce stress, promote calm gilt behaviour and strong standing reflexes during insemination.

Service

Using AI effectively

• Gilts are notorious for taking a long time to inseminate
• Only skilled AI operators should inseminate gilts as it can be more difficult to gauge the correct moment to inseminate and is occasionally more difficult to obtain a catheter lock
• If you have employed a gilt familiarisation routine and have also provided a small (typically 2 m x 2 m) specialist AI pen with excellent boar contact, then the only options are patience or using insemination stalls and/or insemination aids

Using natural and AI together

If this service combination is used, it is important that:

• The gilt is familiar with the chosen boar and service pen
• The boar and gilt body sizes are correctly matched
• Younger boars are supervised and not overworked
• The boar service should be the first service in the oestrus period, followed 18–24 hours later with an artificial insemination

Service to first farrowing

Some producers feed a gilt-rearer diet during the first gestation. These diets generally contain a higher level of lysine (0.7%), which promotes further deposition of lean tissue as the gilt grows and matures. You should seek advice on diet curve and specification from your unit veterinarian, genetics supplier and nutritionist.

First lactation

The first lactation is a critical time for the gilt. It is important that you minimise any loss of body condition, while ensuring that udder function is maximised by her suckling as large a litter as possible to ensure all functional teats are suckled. Feeding a high-specification lactation diet containing at least 1% lysine and 14.5 MJ DE/kg and employing feeding regimes to encourage daily intake is essential.

• Maintain a room temperature between 16–18ºC
• Ensure there is a good supply (2.0 l/min) of clean water and consider providing extra water at feeding
• Use the Stotfold feeding curve to gradually increase daily intake and prevent stalling
• Feed three times a day for at least the last week of lactation